Battery FAQ

CAR AND DEEP

CYCLE BATTERY

FAQ

The Car Battery FAQ was first published on the Internet on June 24, 1995.

Currently, www.batteryfaq.org is redirected and hosted in Germany on

http://www.uuhome.de/william.darden/.









1

CAR AND DEEP CYCLE BATTERY FAQ





Car and deep cycle battery answers to Frequently Asked Questions (FAQs), tips,

manufacturer's information, references and hyperlinks are contained on this consumer

oriented Web site about car, motorcycle, power sports, truck, boat, marine, recreational

vehicle, solar, and other starting and deep cycle applications.









Car Battery Construction (Source: Eurobat)





Car and Deep Cycle Battery Frequently Asked Questions (FAQ) 5.4



This consumer oriented FAQ contains answers and information

about lead-acid batteries used to start car, motorcycle, truck, boat,

recreational vehicle (RV), power sports, motor home, tractor and

other engines. It also answers questions about golf cart, EV, traction,

motive, solar, standby, stationary, UPS, network, industrial and other

lead-acid batteries used in deep cycle applications. It covers

charging (and chargers), testing, buying replacement batteries,

installing, myths, overnight draining, removing sulfation, storing, jump

starting, and other topics about car (starting) and deep cycle

batteries. This FAQ was last updated on February 26, 2006 and

broken link checked on December 26, 2005.





2

Battery Manufacturers and Brand Names List



This popular and frequently updated list contains hyperlinks to lead-

acid battery manufacturers' and large distributors' Web sites,

telephone numbers, battery brand names, replacement selector and

fitment guides, and private labeling information. The file size is

approximately 133 KBytes. This list was last updated on February

20, 2006 and broken link checked on December 26, 2005.



Battery Information Links List



This frequently updated list contains hyperlinks to product

information associated with lead-acid batteries, for example,

alternators, cables and wiring products, chargers, converters,

desulfators, generators, inverters, isolators, low voltage disconnects,

jump starters, regulators, solar and PV, switches, test and monitoring

systems, etc. The file size is approximately 133 KBytes. This list was

last updated on February 20, 2006 and broken link checked on

December 26, 2005.



Battery References Link List



This frequently updated list contains hyperlinks to reference

resources about lead-acid batteries, for example, 42-volt,

associations, books, business directories, dealers and distributors,

FAQs, glossaries, history, hyperlink lists, magazines, magazine

articles, manuals, primers, newsgroups, safety, standards, etc. The

file size is approximately 67 KBytes. This list was last updated on

February 4, 2006 and broken link checked on December 26, 2005.



Battery.Zip



A zipped version of all the current battery related HTML documents

and graphics on this Web site can be easily down loaded to your

computer. Just create a directory for the FAQ and unzip into it. The

file size is approximately 958 KBytes. This zip file was last updated

on February 26, 2006.



I will be happy to try and answer your lead-acid battery and charging questions.

Historically, over 80% of the questions I receive have already been answered in the FAQ

posted on this Web site, so please check it first. Some of the e-mails I receive do not

have a valid return address, so please inclose a valid "Reply To:" e-mail address in your

message and include a "Subject:" that will not be blocked by your spam filter or firewall.

All e-mail received with a virus, spam or worm will be automatically deleted. For

comments, suggestions, broken link notifications or questions, please e-mail Bill Darden

at info@batteryfaq.org or william.darden@uumail.de.





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I highly recommend that you hyperlink to http://www.batteryfaq.org/ rather than republishing this

document because this information will be frequently revised to keep up with the advancements

in batteries and the changing resources and hyperlinks. Revisions will be indicated with a more

recent date or higher version number. These documents are in the public domain and can be

freely reproduced or distributed without permission. Attribution is always appreciated, but not

required.



The Car Battery FAQ was first published on the Internet on June 24, 1995. Currently,

www.batteryfaq.org is redirected and hosted in Germany on

http://www.uuhome.de/william.darden/. This Web site is currently logging over 394,000 "hits" in

January, 2006.









4

CAR AND DEEP CYCLE BATTERY

FREQUENTLY ASKED QUESTIONS 5.4

Bill Darden



Last Updated on February 26, 2006





Words of caution: Lead-acid batteries contain a diluted sulfuric acid electrolyte, which is

a highly corrosive poison and will produce flammable and toxic gasses when recharged

and explode if ignited. According to PREVENT BLINDNESS AMERICA, in 2003 nearly

6,000 motorists suffered serious eye injuries from working around car batteries. When

working with batteries, you need to wear glasses (or preferably safety goggles), have

plenty of ventilation, remove your jewelry, and exercise caution. Do NOT allow battery

electrolyte to mix with salt water. Even small quantities of this combination will produce

chlorine gas that can KILL you! Please follow the manufacturer's instructions for testing,

jumping, installing, discharging, charging, equalizing and maintaining batteries.









[Source: BCI (Battery Council International)]







Car batteries are used to start a gasoline or diesel engines found in approximately 370 million

cars, light trucks and vans worldwide. This FAQ also applies to an estimated 130 million

additional starting batteries found in trucks, SUVs, motorcycles, recreation vehicles (RVs), motor

homes, caravans, boats, power sports (snowmobiles and jet skis), tractors, etc. This FAQ

assumes 12-volt, six cell, negative grounded, lead-acid car and deep cycle batteries at

80° F (26.7° C) with capacities from 5 Amp Hours (AH) to 250 AH. The terms "starting", "SLI"

and "cranking" are used for Car batteries but would apply to any lead-acid battery used to start

an engine. When used alone, the generic term "battery", applies to both lead-acid car, other

starting, motive and stationary deep cycle batteries. For 6-volt batteries, divide the 12-volt

battery voltages in this FAQ by two; for 8-volt batteries, divide by 1.5; for 24-volt batteries,

double the voltage; for 36-volt batteries, triple the voltage; and for 48-volt batteries, multiply by

four. Hyperlinks to battery glossaries and dictionaries can be found in the Battery References

Link List on http://www.batteryfaq.org/.



Warnings and other important information are in BOLD text, and the technical stuff,

recommendations and tips are in italics.







5

CONTENTS

1. WHAT IS THE BOTTOM LINE AND TIPS?



2. WHY BOTHER?



3. HOW DO I PERFORM PREVENTIVE MAINTENANCE?



4. HOW DO I TEST A BATTERY?



5. HOW DO I KNOW IF MY VEHICLE'S CHARGING SYSTEM IS OK OR LARGE ENOUGH?



6. HOW DO I JUMP START MY VEHICLE?



7. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY?



8. HOW DO I INSTALL NEW BATTERIES?



9. HOW DO I CHARGE (OR EQUALIZE) MY BATTERY?



10. WHAT CAUSES MY BATTERY TO DRAIN OVERNIGHT?



11. HOW CAN I INCREASE THE LIFE OF MY BATTERY?



12. WHAT ARE THE COMMON CAUSES OF PREMATURE BATTERY FAILURES?



13. HOW CAN I STORE BATTERIES?



14. WHAT ARE THE MYTHS ABOUT BATTERIES?



15. HOW LONG CAN I PARK MY VEHICLE?



16. HOW CAN I REVIVE A SULFATED BATTERY?



17. WHY WON'T MY ENGINE START?



18. WHERE CAN I FIND MORE INFORMATION ON BATTERIES?



19. HOW CAN I PRINT THIS FAQ?



The best source of information about your battery is the manufacturer who made it. Some

manufacturers do any excellent job of informing and educating their customers about their

batteries, by enclosing the information with each battery and on their Web sites. Ideally, the

battery manufacturer should print the most important consumer information on the battery label

such as capacities, 100% State-of-Charge definitions, charging voltages, etc. If the information

6

is not readily available, ask the manufacturer to provide it. If they are unwilling, use another

manufacturer's product. This information is absolutely essential to properly charging and

maintaining the battery and obtaining the optimal performance and service life from your

investment.









1. WHAT IS THE BOTTOM LINE AND TIPS?



Last Updated on December 25, 2005





BOTTOM LINE:



The three major keys to longer battery service life are:



 Using the battery manufacturer's recommended charging

voltages and procedures



 Reducing the average Depth-of-Discharge



 Practicing good preventive maintenance



TIPS:



1.1. Please wear glasses when working with a lead-acid battery in the unlikely event it

might explode from the gasses produced during charging. Safety First!



1.2. For a starting battery, at the first signs of slow starting, dim headlights at low RPM,

ammeter indicating discharge at higher RPM, or if the battery seems to be losing

performance, fully recharge the battery, remove the surface charge, and load test it and

the charging system. Some auto parts or battery stores will test your battery, charging

system or starter for free. Weak or bad batteries can also cause stress or premature

failures of charging systems and starters and vice versa. (Please see Section 4.)



1.3. Perform regular preventive maintenance on starting and deep cycle batteries, especially

during hot weather and before cold weather. Keep the battery top clean, cable mating

surfaces, posts and terminals free from corrosion, and routinely tighten cable connections

and retention alternator belts. Keep non-sealed wet batteries (with filler caps) filled to the

proper level with distilled, deionized or demineralized water, but do not overfill or use tap

water. The plates must be covered at all times to prevent internal battery explosions or

sulfation. (Please see Section 3.)



1.4. In hot climates and keep the starting battery as cool as possible. For under the hood,

use a non-sealed wet starting battery (with filler caps so you add water) or a sealed spiral

wound AGM VRLA battery. (Please see Section 7.)



1.5. For batteries not in weekly use, people kill more deep cycle and starting batteries

with bad charging practices than die of old age. To prevent permanent sulfation and

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especially in hot weather, in a well ventilated area, keep the battery continuously

connected to a "smart", float charger matched to the battery type or recharge the battery

whenever it drops below 80% State-of-Charge (SoC), or use VRLA (AGM or Gel Cell)

batteries. A cheap, unattended, unregulated "trickle" charger can destroy a battery

by overcharging it. (Please see Section 9.)



1.6. When buying a replacement starting battery, buy the heaviest and freshest battery

compatible with the vehicle's charging system, with the largest Reserve Capacity (RC)

and longest free replacement warranty that will physically fit in your vehicle, and sized

with the cranking amp rating for the coldest climate the engine is started in. For deep

cycle batteries, buy the freshest and heaviest battery with thickest plates and Amp Hour

(AH) capacity that best suits the application, matches the charger, and has the lowest

Total Cost of Ownership. (Please see Section 7.)



1.7. Avoid a deep discharge (below 20% State-of-Charge or 12.0 VDC) of the battery

because this could prematurely kill it (due to cell reversal). After deep discharges or

jump-starts, fully recharge a starting battery with an external charger, remove the surface

charge, and load test the battery and charging system for latent damage. (Please see

Section 4.)



1.8. Temperature and temperature compensation matter! Heat kills batteries and cold

reduces their available capacity.



1.9. For longer battery life, do not add battery acid (except to replace electrolyte spills) or

additives, keep your battery securely fastened, recharge batteries within 24 hours of

each use, use thicker plates, and if recommended by the battery manufacturer, equalize

it. Lowering the average Depth-of-Discharge (DoD) percentage will significantly increase

the service life of any lead-acid battery. (Please see Section 11.)



1.10. For starting and motive deep cycle batteries, match the charging system (or charger's

settings) to the battery type and insure that the charging system produces enough power

to keep the battery fully charged based of your electrical use and driving habits. Use

battery charger (or charger settings) sized not to exceed 25% of the total Amp Hour

battery capacity and adjusted to the battery manufacturer's recommended charging

voltages with good ventilation, especially when recharging wet non-sealed batteries

(with filler caps). A better approach is to slowly recharge your starting and deep cycle

batteries over eight to ten hours.



1.11. For negative grounded systems, always jump start 12-volt batteries POSITIVE (+)

terminal to POSITIVE (+) terminal and NEGATIVE (-) terminal to the frame or engine

block away from the battery to greatly reduce the risk of a battery explosion. (Please see

Section 6.)



1.12. For deep cycle batteries, avoid a shallow discharges (less than 10%) or deep

discharges (below 20% State-of-Charge or 12.0 VDC). This could prematurely kill

them. Using an adjustable low voltage disconnect set at 20% State-of-Charge or

approximately 12.0 VDC or more will increase the batteries' service life and help protect

the batteries and valuable electronic and electrical appliances. (Please see Section 11.)





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1.13. Do NOT use wet lead-acid batteries around salt water. If salt water is mixed with

the battery's electrolyte, deadly chlorine gas is produced. Only use sealed AGM or

Gel Cell VRLA batteries around salt water.



1.14. Remove the surface charge before testing. For non-sealed batteries (with filler caps),

and use a temperature compensating hydrometer to check Specific Gravity in each cell

because it is more accurate than a DC voltmeter. For sealed batteries, use a accurate

(.5% or better) digital DC voltmeter and manually compensate for the electrolyte

temperature. (Please see Section 4.)



1.15. If the temperature is below 0 degrees F (-17.8 degrees C) and you are not using an AC

powered engine block and battery warmer or if the vehicle can not be parked in a warmer

location, then disconnect the battery, take it indoors, keep it fully charged, and reconnect

it just before starting the engine. (Please see the CCA vs. Temperature Diagram in

Section 7.2) Alternatively use two 12-volt AGM batteries in parallel and a low viscosity

synthetic oil in the engine. Batteries that have less than a 40% State-of-Charge will

freeze at 0 degrees F (-17.8 degrees C) and fully discharged batteries will freeze at

approximately 20 degrees F (-6.7 degrees C).









9

2. WHY BOTHER?



Last Updated on December 26, 2005





INDEX:



2.1. How Is a Battery Made?



2.2. How Does a Battery Work?



2.3. How Do Batteries Die?



2.4. Why Are Vehicles Negatively Grounded?



Because only the rich can afford cheap batteries.....



A lead-acid battery (also know as an "accumulator") is a secondary (rechargeable)

electrochemical device that stores chemical energy and releases it as electrical energy upon

demand. When a battery is connected to an external device, such as a motor, chemical energy

is converted to electrical energy and direct current flows through the circuit. The terms of the

quantity of lead-acid batteries that are produced, starting batteries represent approximately 88%

of the total. The total breaks down to 65% Car, 23% Other Starting Batteries (motorcycle, etc.),

8% Deep Cycle Motive (wheelchairs, golf carts, fork lift trucks, etc.), and 4% Deep Cycle

stationary (backup, UPS, standby, etc.).



BATTERY PRODUCTION









In the order of importance, the four major purposes of a car or "SLI" (Starting, Lighting and

Ignition) battery, as it is known in the battery industry, are:



 To start the engine.





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 To filter or stabilize the pulsating DC power from the vehicle's

charging system.



 To provide extra power for the lighting, two-way radios, audio system

and other accessories when their combined load exceeds the

capability of the vehicle's charging system. This commonly occurs

while the vehicle's engine is idling or during short trips with a heavy

power load like at night in bad weather.



 To supply a source of power to the vehicle's electrical system when

the charging system is not operating.







A good quality car battery will cost between $50 and $100 and, if properly maintained, it should

last five years or more. With a 5% compounded annual growth rate, worldwide retail sales of car

lead-acid batteries represent roughly 63% of the estimated $30 billion annually spent on

batteries. In North America, BCI reports that of the 106.6 million car batteries that were sold in

2001, of which approximately 80% were for replacement and 20% were for original equipment.

For 2003, Eurobat estimates that in Western Europe 58.5 million car batteries will be sold and

71% will be replacement (after market) and 29% will be OEM (Original Equipment

Manufacturer). At the Robert W. Baird Industrial Technology Conference, Johnson Controls

reported that approximately 350 million starting batteries will be made in the world in 2004. Of

that, Johnson Controls is the largest manufacturer with 31% of the total followed by Exide with

14%, GS Yuasa (pending merger of Yuasa and Japan Storage Battery) with 10%, Matsushita

with 4%, East Penn with 3%, FIAMM with 3%, and all others with 35%. In another marketing

study by Recharge, in 2003 the worldwide battery market was roughly $30 billion, with 30% of

that being SLI (car) and 15.3% industrial (deep cycle) lead-acid batteries.



The purpose of a deep cycle battery is to provide power for wheelchairs, trolling motors, golf

carts, boats, fork lift trucks, uninterruptible power supplies (UPS), and other accessories for

marine and recreational vehicle (RV), commercial and stationary applications. A good quality

wet deep cycle (or "leisure") battery will cost between $50 and $300 and, if properly maintained

and used, will give you at least 200 deep discharge-charge cycles. For differences between a

car and deep Cycle battery, please see Section 7.1.8. Purportedly, Exide and EnerSys are the

two largest deep cycle battery manufacturers in the world.



2.1. How is a Battery Made?



A 12-volt lead-acid battery is made up of six cells, each cell producing

approximately 2.1 volts that are connected in series from POSITIVE (+) terminal of

the first cell to the NEGATIVE (-) terminal of the second cell and so on. Each cell

is made up of an element containing positive plates that are all connected together

and negative plates, which are also all connected together. They are individually

separated with thin sheets of electrically insulating, porous material "envelopes" or

"separators" (in the diagram below) that are used as spacers between the positive

(usually light orange) and negative (usually slate gray) plates to keep them from

electrically shorting to each other. The plates (in the diagram below), within a cell,

alternate with a positive plate, a negative plate and so on.



11

CAR BATTERY CONSTRUCTION









[Source: Eurobat]



DEEP CYCLE BATTERY CONSTRUCTION









[Source: US Department of Energy]







The most common plate in use today is made up of a metal grid that serves as the

supporting framework for the active porous material that is "pasted" on it. After the

"curing" of the plates, they are made up into cells, and the cells are inserted into a

high-density tough polypropylene or hard rubber case. The positive plates in cells

are connected in parallel to the external POSITIVE (+) terminal and the negative

plates in each cell are connected to the NEGATIVE (-) external terminal. Instead

of pasted Lead Oxide, some batteries are constructed with more expensive solid

lead cylindrical (spiral wound); Manchester or "Manchex" (buttons inserted into the

grid); tubular; or prismatic (flat) solid lead (Planté) positive plates. The case is

covered and then filled with a dilute sulfuric acid electrolyte. The battery is initially

charged or "formed" to convert the active yellow Lead Oxide (PbO or Litharge) in

the positive plates (cathode) into Lead Peroxide (PbO2), which is usually dark

brown or black. The active material in the negative pasted plates (anode)

becomes sponge Lead (Pb), but with a very porous structure which is slate gray.

If sponge Lead is rubbed with a hard object, it will be silvery in color. The

electrolyte is replaced and the battery is given a finishing charge. A "Wet charged"

battery is a wet lead-acid battery shipped with electrolyte in the battery and a "dry

charged" battery is shipped without electrolyte. When dry charged batteries are

sold, electrolyte (battery acid) is added, allowed to soak into the plates, charged

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(or "formed"), and put into service. This avoids having to maintain the batteries

until they are sold.









PASTED PLATE









[Source: BCI]



FLAT AND TUBULAR PLATE









PLANTE PLATÉ









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[Source: US Department of Energy]









SPIRAL WOUND PLATE









[Source: US Department of Energy]



Two important considerations in battery construction are porosity and diffusion.

Porosity is the pits and tunnels in the plate that allows the sulphuric acid to get to

the interior of the plate. Diffusion is the spreading, intermingling and mixing of one

fluid with another. When you are using your battery, the fresh acid needs to be in

contact with the plate material and the water generated needs to be carried away

from the plate. The larger the pores or warmer the electrolyte, the better the

diffusion.









[Source: Varta]





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There is an excellent detailed description of how battery is made, equipment used

and quality assurance on the Best Manufacturing Practices Web site at

http://www.bmpcoe.org/library/books/navso%20p-3676/index.html.







2.2. How Does a Battery Work?







DISCHARGING PROCESS



PbO2 + Pb + 2H2SO4 → 2PbSO4 + H2O









CHARGING PROCESS (Reverse of Discharging Process)



2PbSO4 + H2O → PbO2 + Pb + 2H2SO4



A battery is created by alternating two different metals such as Lead Dioxide

(PbO2), the positive plates, and Sponge lead (Pb), the negative plates. Then the

plates are immersed in diluted Sulfuric Acid (H2SO4), the electrolyte. The types of

metals and the electrolyte used will determine the output of a cell. A typical fully

charged lead-acid battery produces approximately 2.11 volts per cell. The

chemical action between the metals and the electrolyte (battery acid) creates the

electrical energy. Energy flows from the battery as soon as there is an electrical

load, for example, a starter motor, that completes a circuit between the positive

terminal connected to the positive plates and the negative terminal connected to

the negative plates. Electrical current flows as charged portions of acid (ions)

between the battery plates and as electrons through the external circuit. The

action of the lead-acid storage battery is determined by chemicals used, State-of-

Charge, temperature, porosity, diffusion, and load. A cycle is defined as one

discharge and one recharge of the battery.



A more detailed description of how a battery works can be found on the BCI web

site at http://www.batterycouncil.org/works.html.







2.3. How do Batteries Die?



When the active material in the plates can no longer sustain a discharge current,

the car battery "dies". Normally a battery "ages" as the active positive plate

material sheds (or flakes off) due to the normal expansion and contraction that

occurs during the discharge and charge cycles. This causes a loss of plate

capacity and a brown sediment, called sludge or "mud," that builds up in the

bottom of the case and can short the plates of a cell out. In hot climates, additional

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causes of failure are positive grid growth, positive grid metal corrosion, negative

grid shrinkage, buckling of plates, or loss of water. Deep discharges, heat,

vibration, fast charging, and overcharging all accelerate the "aging" process. At

approximately 50%, the number one cause of premature car battery failure is

loss of water caused from high under hood heat or overcharging. Positive

grid growth and undercharging causing sulfation also cause a lot of failures.

For deep cycle and starting batteries that are not used weekly it is sulfation,

at an estimated 85%. Sulfation is caused when a battery's State-of-Charge drops

below 100% for long periods or under charging. Hard lead sulfate crystals fills the

pours and coats the plates. Please see Section 16 for more information on

sulfation. Recharging a sulfated battery is like trying to wash your hands with

gloves on.



In a hot climate, the harshest environment for a battery, a Johnson Controls

survey of junk batteries revealed that the average life of a car battery was 37

months. In a separate North American study by BCI, the average life was 48

months. In a study by Interstate Batteries, the life expectancy in extreme heat was

30 months. If your car battery is more than three years old and you live in a hot

climate, then your battery is probably living on borrowed time. Abnormally slow

cranking, especially on a cold day, is another good indication that your battery is

going bad. It should be externally recharged, surface charge removed, and load

tested. Dead batteries almost always occur at the most inopportune times. You

can easily spend the cost of a new battery or more for an emergency jump start,

tow or taxi ride.



Most of the "defective" batteries returned to manufacturers during free

replacement warranty periods are good. This strongly suggests that some sellers

of new batteries do not know how to or fail to take the time to properly recharge

and test batteries. This situation is improving with the widespread use of easy to

use conductance type battery testers like those made by Midtronics and Cadex.

They are used to predict the capacity of the batteries without having to fully

recharge them first.







2.4. Why Are Vehicles Negatively Grounded?



The best explanation to this question comes from a 1978 Rolls-Royce Enthusiasts'

Club service manual.



"...it has been found that cars wired positive earth [ground] tend to

suffer from chassis and body corrosion more readily than those wired

negative earth. The reason is perfectly simple, since metallic

corrosion is an electrolytic process where the anode or positive

electrode corrodes sacrificially to the cathode. The phenomenon is

made use of in the "Cathodic Protection" of steel-hulled ships and

underground pipelines where a less 'noble' or more electro-negative

metal such as magnesium or aluminum is allowed to corrode

sacrificially to the steel thus inhibiting its corrosion."...



16

For more information on cathodic protection, please read Roger Alexander's

article, An idiots guide to cathodic protection. By 1956, all the North American

manufactured cars and trucks, except the Metropolitan, were using negative (or

earth) grounding. For more specific information on grounding systems used in

North American vehicles, please go to Antique Automobile Radio's chart on

http://www.antiqueautomobileradio.com/battery.htm.



.









17

3. HOW DO I PERFORM PREVENTIVE MAINTENANCE?



Last Updated on December 28, 2005





Performing preventive maintenance on batteries is easy and should occur at least once a month

during hot weather and every three months in cold weather. While working with car and deep

cycle lead-acid batteries (and corrosion), please wear glasses to protect your eyes in the

unlike even of an explosion. Here are some simple steps to maintain your battery:



3.1. Before you start the engine for the first time during the day, check the electrolyte level

for non-sealed wet batteries (with filler caps). If above the plates and for all other battery

types, check the State-of-Charge (SoC) of the battery. Please see Section 4.4 for more

information on determining the SoC. If the battery is not fully charged (100% State-of-

Charge), recharge it with an external battery charger in a well ventilated area. Please see

Section 9 for more information on charging. This is because State-of-Charge is based on

your driving habits. Some vehicle charging systems have been known to consistently

undercharge the battery causing an accumulation of lead sulfate, know as sulfation. A

gradual build up of sulfation will reduce the capacity of the battery.



3.2. The plates need to be covered at all times to prevent sulfation and reduce the

possibility of an internal battery explosion. For non-sealed wet batteries (with filler

caps), if the electrolyte levels are low, allow the battery to cool to room temperature first

and then add only distilled, deionized or demineralized water to the level indicated by the

battery manufacturer or to within 1/4 to 3/8 inch (6 to 10 mm) below the bottom of the

filler tubes (vent wells or splash barrels) on large deep cycle batteries (greater than 200

amp hours) and less on smaller batteries. Avoid overfilling, especially in hot weather,

because the heat will cause the electrolyte to expand and overflow. In an emergency, use

rain water rather than residential Reverse Osmosis (RO) from residential systems or tap

water because rain water does not contain chlorine, calcium or magnesium. Using RO or

tap water to refill batteries can produce chlorine gas or calcium sulfate crystals that can

fill the pores and coat the plates. State-of-Charge (SoC) readings will be inaccurate

immediately after the addition of water, recharges or discharges. Please see Section 4.3.









18

ELECTROLYTE FILL LEVELS FOR LARGER BATTERIES >200 AH









[Source: Mountain Top Golf Cars]



3.3. Tighten loose hold-down clamps, battery terminals and connectors.



3.4. Remove any corrosion, lead oxidation, paint or rust with a brass wire battery brush

(brushing the corrosion away from you) or "ScotchBrite" pad from the terminal's mating

surfaces on both ends of each battery cables, battery posts or terminals, and engine

grounding strap connections. (A stiff steel wire brush may damage protective lead plating

on copper connectors or terminals.) Heavy corrosion can be neutralized with a mixture of

one pound of baking soda (bicarbonate of soda) to one gallon of warm water. Some folks

have been known to use Diet Coca or Diet Pepsi to dissolve corrosion. Bare metal to

metal mating surfaces are required for good current conductivity. To prevent corrosion on

terminals, thinly coat the terminals, terminal clamps and exposed metal around the car

battery with high temperature wheel bearing grease or silicone. Gluing a sacrificial anode,

such as a penny or a piece of copper to the top of the battery will prevent or reduce

terminal corrosion. Do not use the felt or metal washers between the mating conductive

surfaces with General Motors-type side terminals.



For deep cycle batteries, use "No Oxide A" (or the battery manufacturer's

recommended grease) on the terminals and connectors. Do not use the felt or

metal washers between the mating conductive surfaces with side, stud or "L"

terminal batteries. Use of some stainless steel alloys and other metal washers,

nuts and bolts have also been known to cause problems with electrolysis and high

resistance.



Corrosion is caused by one or more the following:



19

 Dirty or wet battery tops normally caused from expansion of

electrolyte from overfilled cells or weeping form faulty battery

terminal seals



 Acid fumes leaking through the vent caps, which could be a sign of

overcharging



 Electrolysis due to the mismatch of metal alloys used in the battery

posts and terminals







3.5. Clean the battery top to eliminate conductive paths created by dried or wet electrolyte

and to prevent corrosion.



3.6. Clean the alternator or charging system to allow better heat transfer and check the

alternator belts for cracks and correct tension.



3.7. Replace any battery cables (or cable terminals) that are corroding, swelling or damaged

with equal or larger diameter cable. If electrical problems are experienced in vehicles with

GM's side terminal connectors, check for corrosion inside the positive terminal with the

multiple cables. Larger cable and cable connectors are better because there is more

surface area and less voltage drop. Please see Exide's Voltage Drop in Cables for

additional information.



3.8. Replace the battery if the battery case is cracked or leaking, especially around "GM"

style side terminals.









20

4. HOW DO I TEST A BATTERY?



Last Updated on December 26, 2005





INDEX:



4.1. Inspect



4.2. Charge



4.3. Remove Surface Charge



4.4. Measure State-of-Charge (SoC)



How Do I Use a Hydrometer?



Low Maintenance and Standard Battery State-of-Charge (SoC) Table



Maintenance Free and VRLA Battery State-of-Charge (SoC) Table



State-of-Charge (SoC) Temperature Compensation Table



4.5. Capacity Load Test



Capacity Load Test Table



4.6. Bounce Back Test



4.7. Recharge



4.8. Refill



While working with car and deep cycle lead-acid batteries, please help to prevent

blindness and wear glasses in the unlikely event of an explosion. Below are eight simple

steps in testing a car or deep cycle battery. Alternatively, some auto parts or battery stores in

the United States and Canada, like Auto Zone, Sears, Wal-Mart, Pep Boys, etc., will test your

battery, charging system and starter for free. If you have a non-sealed wet battery (with filler

caps), it is highly recommended that you use a good quality temperature compensating

hydrometer, like an E-Z Red SP101, which can be purchased online at BatteryStuff.com or at an

auto parts or battery store for less than $10.



If you have a sealed battery or need to troubleshoot a charging or electrical system, you will

need a digital voltmeter with 0.5% (or better) DC accuracy, such as a Fluke 73-3 or 175. A

digital voltmeter (or multimeter) can be purchased at an electronics store for between $20 and

$200. A good, free digital multimeter applications manual for testing electrical systems is

available on-line from Fluke at

http://us.fluke.com/usen/support/appnotes/default?category=AP_AUTO(FlukeProducts). Analog

21

voltmeters are not accurate enough to measure the millivolt differences of a battery's State-of-

Charge or output of the charging system. Do not use a 12-volt test light to troubleshoot

vehicle electrical circuits, except for testing the parasitic load at the battery, because you

might damage the emissions computer or other sensitive electronic devices. A good

source of information on measuring voltage and for maximum voltage drops can be found at

Exide's Caring For Your Battery. A battery load tester is optional. Another way of testing the

CCA (Cold Cranking Amp), amp hour (AH) or Reserve Capacity (RC) of lead-acid car or deep

cycle batteries is using an electro-chemical impedance spectroscopy (EIS) tester, such as a

Cadex Spectro CA-12 or a conductance terter, for example a Midtronics. A sulfated sealed

battery's voltage often will read higher than the SoC actually is, so capacity testing maybe

required to determine the battery's condition.







4.1. Inspect



Visually inspect for obvious problems such as a low electrolyte levels; loose,

corroded or swollen cables, corroded battery terminals or posts; loose or broken

alternator belt; frozen battery; loose hold-down clamps; dirty or wet battery top; or

a leaking, cracked or damaged battery case. If the electrolyte levels are below the

tops of the plates, add enough distilled, deionized or demineralized water to cover

the plates and recharge the battery, allow to cool to room temperature and then

top off the levels. The plates need to be covered at all times to prevent

sulfation and reduce the possibility of an internal battery explosion. Please

see Section 3.2 for electrolyte fill level diagram.



4.2. Charge



Charge the battery to 100% State-of-Charge in a well ventilated area. If non-

sealed battery has a .030 (sometimes expressed as 30 "points") or more

difference in specific gravity reading between the lowest and highest cell or if a cell

is .010 or 10 "points" below the reading for a fully charged cell, then you should

equalize the battery using the battery manufacturer's procedures. (Please see

Section 9.)







4.3. Remove Surface Charge



Surface charge (or counter voltage) is the uneven mixture of sulfuric acid and

water along the surface of the plates as a result of charging or discharging as the

electrolyte has an opportunity to diffuse in the pores of the plates. It will make a

weak battery appear good or a good battery appear bad. Larger wet lead-acid

batteries (especially over 100 amp hours) could also have electrolyte stratification

where the concentration of acid is greater at the bottom of the cell than near the

surface. Open Terminal Voltages will read higher than they actually are.

Stratification can be eliminated by an equalizing charge, stirring or shaking the

battery to mix the electrolyte.





22

The surface charge can be eliminated by one of the following methods after

recharging a lead-acid car battery:



 Allow the battery to sit (or rest) without discharge or charge for

between six to twelve hours at room temperature, if possible, to allow

for the surface charge to dissipate. (Recommended method.)



 Turn the headlights on high beam for five minutes, turn them off, and

wait ten minutes.



 With a battery load tester, apply a load at one-half the battery's CCA

rating for 15 seconds and then wait ten minutes.



 Disable the ignition, turn the engine over for 15 seconds with the

starter motor, and wait ten minutes.



 Apply a load that is 33% of the ampere-hour capacity for five minutes

and wait ten minutes.



4.3.6. With a battery load tester, apply a load is one third the battery's amp-hour rating for

five minutes and wait minutes.







4.4. Measure the State-of-Charge (SoC)



The State-of-Charge only measures the state of the battery's charge and not

capacity. For capacity measurements, please see Section 4.5, below. For

example, a 50% SoC reading does not necessarily mean that a 100 amp hour

(C/20) battery will produce 50 amp hours at five amp hour over 20 hour discharge

rate. Use a hydrometer to measure the Specific Gravity. It is a more accurate way

of determining a wet lead-acid battery's SoC than using a digital voltmeter. When

the SoC measured by a hydrometer does not materially agree with the SoC

measured by a voltmeter, it is probably caused by sulfation. If you suspect that a

battery is sulfated, it probably is, especially if it has not been charged in a while or

has been continuously undercharged. For more on sulfation, please see

Section 16









HOW DO I USE A HYDROMETER?

A hydrometer is an inexpensive a float-type device used to measure the concentration of

sulfuric acid (Specific Gravity) of battery electrolyte ("battery acid"). From this reading you

can easily and accurately determine a non-sealed battery's State-of-Charge. A

hydrometer is a glass barrel or plastic container with a rubber nozzle or hose on one end

and a soft rubber bulb on the other. Inside the barrel or container, there is a float and

calibrated graduations used for the Specific Gravity measurement. The following is a list



23

of instructions on how to correctly use a battery hydrometer:



BATTERY HYDROMETERS









[Source: Popular Mechanics]









24

[E-Z Red SP101]



1. If the battery has been charged within the last four hours, remove the Surface Charge. If

the battery has been discharged within the last 15 minutes, wait for at least 15 minutes

before testing it.



2. Find some glasses, preferably safety glasses, and put them on in the unlikely event that a

battery explosion or electrolyte spill might occur.



3. While holding a clean hydrometer vertically, squeeze the rubber bulb, insert the nozzle

into the electrolyte in the cell, and release the bulb. The electrolyte will be sucked up into

the barrel or container allowing the float to ride freely. Start with the cell that is closest to

the POSITIVE (+) terminal.







25

4. Tap the hydrometer to dislodge any air bubbles on the float.



5. Squeeze the rubber bulb to release the electrolyte back into the battery's cell.



6. To increase the accuracy of the measurement, in the same cell, repeat this process

several times so the float will reach the same temperature as the electrolyte. If you are

measuring a large battery, stratification can occur when the more concentrated

electrolyte settles to the bottom. If you notice a difference in the readings between the top

and bottom of the cell, average the two readings.



7. At eye level and with the float steady, read the Specific Gravity at the point the surface of

the electrolyte crosses the float markings. The Specific Gravity reading should be

between 1.100 and 1.300.



8. Release the electrolyte back into the cell from which it was taken and record the reading.

Be sure to avoid spillage.



9. If the hydrometer is not temperature compensating, measure the electrolyte temperature.

If the electrolyte temperature is not 80° F (26.7° C), then adjust the reading using the

Temperature Compensation Table and examples in Section 4.4 and determine the State-

of-Charge from the SoC Table. If the hydrometer is temperature compensating,

determine the State-of-Charge directly from the SoC Table.



10. Repeat the process for each individual cell. The Specific Gravity reading should not have

a difference of more that 30 "points" (.030) between the lowest and highest reading or 10

"points" (.010) below the battery manufacturer's recommended temperature value with

the battery fully charged. If so, try and equalize the the battery by following the battery

manufacturer's procedures or the procedure in Section 9. If equalizing does not help,

replace the battery. You can determine the battery's State-of-Charge by taking the

average of the temperature compensated cell readings, but the battery's performance will

be based on the weakest cell.



11. Throughly rinse the hydrometer with water after using it.









If the battery's electrolyte is above 125° F (51.5° C), allow it to cool. To determine

the battery's SoC with the battery's electrolyte temperature at 80° F (26.7° C),

please use the one of the following tables depending on battery type. The Low

Maintenance and Standard Battery SoC table has a baseline that assumes

that a 1.265 Specific Gravity (SG) and 12.65 Open Circuit Voltage (OCV)

reading is a fully charged (100%), wet, Low Maintenance (Sb/Ca) or Standard

(Sb/Sb) lead-acid battery at rest and with an open circuit (no external current

running through it and the negative battery cable disconnected). The

Maintenance Free and VRLA Battery SoC table has a baseline that assumes

that a 12.8 Open Circuit Voltage (OCV) reading is a fully charged (100%),

Valve Regulated (AGM or Gel Cell) Lead-Acid (VRLA) battery at rest and with

an open circuit (no external current running through it and the negative

battery cable disconnected). For electrolyte temperatures other than 80° F

26

(26.7° C), please use the Temperature Compensation table below to adjust the

Open Circuit Voltage (OCV) or Specific Gravity readings. The Specific Gravity or

OCV readings for a battery at 100% SoC will vary by plate chemistry, so

check the battery manufacturer's specifications for their State-of-Charge

definitions for your battery. If you do not know the baseline for your battery

at 100% SoC, please see Section 9.5. How Do I Know When My Battery Is

Fully Charged? A fully charged wet battery at 80° F (26.7° C), can range from

1.215 to 1.300 Specific Gravity (12.22 to 13.00 VDC) and a sealed VRLA Gel Cell

or AGM battery from 1.285 to 1.310 (12.85 to 13.1 VDC).







LOW MAINTENANCE (Sb/Ca) AND STANDARD

(Sb/Sb)

BATTERY STATE-OF-CHARGE (SoC)

Digital Approximate Approximate Hydrometer Approximate

Voltmeter State-of- Depth-of- Average Cell Electrolyte

Open Circuit Charge at Discharge at Specific Freeze Point

Voltage at 80°F (26.7°C) 80°F (26.7°C) Gravity

Rest

12.65 100% 0% 1.265 -77°F

(-67°C)

12.45 75% 25% 1.225 -35°F

(-37°C)

12.24 50% 50% 1.190 -10°F

(-23°C)

12.06 25% 75% 1.155 15°F

(-9°C)

11.89 or less DISCHARGED 100% 1.120 or less 20°F

(-7°C)





[Source: BCI]







MAINTENANCE FREE (Ca/Ca) AND VRLA

BATTERY STATE-OF-CHARGE (SoC)

Digital Approximate Approximate

Voltmeter State-of- Depth-of-



27

Open Circuit Charge at Discharge at

Voltage at 80°F (26.7°C) 80°F (26.7°C)

Rest

12.8 100% 0%

12.6 75% 25%

12.4 50% 50%

12.0 25% 75%

11.8 or less DISCHARGED 100%









STATE-OF-CHARGE (SoC)

TEMPERATURE COMPENSATION

Electrolyte Electrolyte Add to Add to Digital

Temperature Temperature Hydrometer's Voltmeter's

Degrees Degrees SG Reading Reading

Fahrenheit Celsius

120° 48.9° +.016 -.013

110° 43.3° +.012 -.011

100° 37.8° +.008 -.008

90° 32.2° +.004 -.005

80° 26.7° 0 0

70° 21.1° -.004 +.007

60° 15.6° -.008 +.016

50° 10° -.012 +.028

40° 4.4° -.016 +.044

30° -1.1° -.020 +.062

20° -6.7° -.024 +.084

10° -12.2° -.028 +.108

0° -17.8° -.032 +.134







Electrolyte temperature compensation, depending on the battery

manufacturer's definition of 100% State-of-Charge, will vary. If you are using a

digital DC voltmeter or a non-temperature compensated HYDROMETER, make

28

the adjustments indicated in the table above. Please note that some battery

manufacturers express their SoC definitions at 77° F (25° C), and some slight

temperature compensation should occur to normalize the definitions at 80° F

(26.7° C) to use the tables above. For example, if the electrolyte is at 80° F

(26.7° C), and the specific gravity reading is 1.265 for a 100% SoC, when the

electrolyte is at 20° F (-6.7° C), the actual specific gravity reading would be 1.289

for a 100% State-of-Charge because the liquid is more dense. However, when you

subtract .024 from 1.289, the corrected reading would be 1.265 or 100% State-of-

Charge. At 100° F (37.8° C), the actual specific gravity reading would be 1.257 for

100% SoC, but the compensated reading, after .008 is added, would be 1.265 for

100% State-of-Charge. This is why using a temperature compensated hydrometer

is highly recommended and more accurate.



If you are using an accurate (.5% or better) DIGITAL DC VOLTMETER, make the

adjustments indicated in the table above. For example, if the electrolyte is at 80° F

(26.7° C), and the voltage reading is 12.65 for a 100% State-of-Charge, when the

electrolyte is at 20° F (-6.7° C), the actual voltage reading would be 12.566 for a

100% State-of-Charge. Before you correct the reading by adding .0843 volts (84.3

millivolts). At 100° F (37.8° C), the actual voltage reading would be 12.658 for

100% SoC.



For wet non-sealed batteries, please check the specific gravity in each cell with a

hydrometer and average cells readings. For sealed batteries, measure the Open

Circuit Voltage (OCV) across the battery terminals with an accurate (.5% or better)

digital DC voltmeter. This is the only way you can determine the battery's SoC.

Some sealed wet batteries have a built-in hydrometer, "Magic Eye", which only

measures the State-of-Charge in ONE of its six cells.



"Magic Eye" Built-in Hydrometer









[Source: Popular Mechanics]



If the State-of-Charge is BELOW 75% using either the Specific Gravity, voltage

test or the built-in hydrometer does not indicate "good" (green or blue), then the

battery has a low charge and needs to be recharged before proceeding. If the

battery is sealed, the battery could have low electrolyte, especially in a hot climate.

You should replace the battery, if one of the following conditions occur:



29

 If there is a .050 (sometimes expressed as 50 "points") or more

difference in the specific gravity reading between the highest and

lowest cell, you have a weak or dead cell(s). Applying an

EQUALIZING charge per the battery manufacturer's procedures may

correct this condition. (Please see Section 9.)



 If the battery will not recharge to a 75% or more State-of-Charge

level or if the built-in hydrometer still does not indicate "good" (green

or blue), which indicates a 65% SoC or better).



 If a moderate load is applied and if there is no or very little current

flowing there is an probably an open cell or a completely sulfated

battery. Without a load, a voltmeter reading may or may not indicate

an open.



 If the digital voltmeter indicates 10.45 to 10.65 volts, there probably

is a shorted cell. A shorted cell is caused by plates touching,

sediment ("mud") build-up or "treeing" between the plates.







4.5. Capacity Load Test



Capacity load testing is to determine how good or bad a car or deep cycle battery

is. The primarily purpose of a car battery is to start an engine, so the battery ability

to produce current is the most important capacity test. In addition, some car

batteries are only rated in their amp hour or Reserve Capacity. If this is the case,

the capacity testing for deep cycle batteries below should be used.



4.5.1. Car Batteries (High Current Method)



If the battery's State-of-Charge is at 75% or higher or has a "good" built-in

hydrometer indication, then you can load test the car battery by one of the

following methods:



 With a battery conductance tester, test the battery. Most auto parts

and battery stores have battery conductance testers and some

stores will test battery capacity for free. (Recommended method).



 With a battery load tester, apply a load equal to one half of the CCA

rating of the battery for 15 seconds.



 With a battery load tester, apply a load equal to one half the OEM

cold cranking amp specification for 15 seconds.



 Disable the ignition and turn the engine over for 15 seconds with the

starter motor.









30

DURING the load test, the voltage on a good car battery will NOT

drop below the following table's indicated voltage for the electrolyte

at the temperatures shown:







Capacity Load Test

Electrolyte Electrolyte Minimum

Temperature Temperature Voltage Under

Fahrenheit Celsius LOAD

100° 37.8° 9.9

90° 32.2° 9.8

80° 26.7° 9.7

70° 21.1° 9.6

60° 15.6° 9.5

50° 10.0° 9.4

40° 4.4° 9.3

30° -1.1° 9.1

20° -6.7° 8.9

10° -12.2° 8.7

0° -17.8° 8.5





[Source: BCI]







4.5.2. Deep Cycle Batteries (Low Current Method)



Motive and stationary deep cycle batteries and car batteries with amp hour

or Reserve Capacity ratings can be capacity tested using a slow discharge

load test. A DC ammeter and a resistive load, for example, 12-volt head

lamps, are required for this test. Please note that this test will not test the

battery's ability to produce enough high current to start an engine, but

normally, if a battery fails this test, it will also fail the high current load

capacity test in Section 4.5.1 above.



If the battery is fully charged after the surface charge has been removed

and you know the Amp Hour rating of the battery, then you can test the

capacity of a battery by applying a specific load and discharging the battery

for 50% of it's rated amp hour capacity as defined by the battery

manufacturer. Normally a discharge rate that will discharge a battery in 20

hours (C/20)is used. For example, if you have an 80 ampere-hour (C/20)

rated battery, then an average load of four amps would discharge the

31

battery to 50% of it's rated amp hour capacity in approximately 10 hours (80

AH/20 Hours = 4 Amps and 50% of 80 AH/4 Amps = 10 Hours). An

example for a C/10 rated battery, would be 80 AH/10 = 8 Amps and 50% of

80 AH/8 = 5 Hours. For an estimate of the battery's capacity, measure the

SoC after removing the surface charge and double the SoC.



If the battery is fully charged after the surface charge has been removed

and you know the Reserve Capacity (RC) rating of the battery, then you

can test the capacity of a battery by applying a 25 amp load and

discharging the battery for 50% of it's rated Reserve Capacity in minutes as

defined by the battery manufacturer. For example, if you have an 120

minute RC rated battery, then discharge the battery with an average load of

25 amps for 60 minutes (50% of 120 minutes = 60 minutes). For an

estimate of the battery's capacity, measure the SoC after removing the

surface charge and double the SoC.



A battery with 80% or more of it's manufacturer's original rated capacity is

considered to be good for most applications. Some new batteries can take

up to 30 charge/discharge "preconditioning" cycles before they reach their

rated capacity. If the deep cycle battery passed the Capacity Load Test,

then skip the next test, Section 4.6 Bounce Back Test and go to

Section 4.7. Recharge below.









4.6. Bounce Back Test



If the car battery has passed the load test, please go to Section 4.7. Recharge

below. If not, remove the load, wait ten minutes, and measure the State-of-

Charge. If the battery bounces back to less than 75% SoC then recharge the

battery (please see Section 9.) and load test again. If the car battery fails the load

test a second time or bounces back to less than 75% SoC, then replace the

battery because it lacks the necessary CCA capacity.









4.7. Recharge



In a well ventilated area, you should recharge your battery to 100% SoC as soon

as possible to prevent lead sulfation and to restore it to peak performance.









4.8. Refill





32

When the non-sealed wet battery (with filler caps) has cooled to room

temperature, recheck the electrolyte levels and, if necessary, fill to the correct

level. Please see Section 3.2 for electrolyte fill level diagram.









33

5. HOW DO I KNOW IF MY VEHICLE'S CHARGING SYSTEM IS OK OR LARGE

ENOUGH?



Last Updated on February 26, 2006





INDEX:



5.1. How Does A Vehicle Charging System Work?



Charging System Functional Diagram



Alternator Output Graph



Vehicle Charging Voltage Graph



5.2. What If My "Battery" or "Alternator" Light Is On? (Or the Gauge Is Not

Showing a "Charging" Condition?)



5.3. What If I Cannot Keep My Battery Charged and the Battery Tests OK?



5.4. How Can I Test To Determine If Charging System Is Large Enough?







5.1. How Does A Vehicle Charging System Work?



Referring to Dan Masters' diagram below, a vehicle's charging system is composed of an

alternator (or DC generator), voltage regulator, battery, and indicator light or gauge.

Another good source of information on the basics of vehicle charging systems can be

found on Perry Babin's Basic Car Audio Electronics Web site at

http://www.bcae1.com/charging.htm. While the engine is running, the charging system's

primary purpose is to provide power for the car's electrical load, for example, ignition,

lighting, audio system, accessories, etc., and to recharge your vehicle's battery. The

alternator's output capacity is directly proportional to the RPM of the engine and

alternator temperature. Charging systems are normally sized by the car manufacturers to

provide at least 125% (when operating at high RPM) of the worst-case OEM (Original

Equipment Manufacturer) electrical load, so that the car battery can be recharged. That is

the reason that short, stop and go driving at night or in bad weather might not keep the

battery fully recharged, especially if the electrical load has been increased with after

market accessories, such as high power audio equipment, lighting or an electric winch.

Vehicle charging systems are not designed to recharge fully discharged batteries

and doing so may damage the stator or diodes from overheating.









34

CHARGING SYSTEM FUNCTIONAL DIAGRAM









[Source: Vintage Triumph Register]



In the Balmar Alternator Output diagram below, the power output curves are shown 65

amp and 85 amp alternator. Note that the 65 amp alternator in this example, produces

more current output (power) at a lower RPM that does the larger alternator until

approximately 3300 RPM. Also note the difference that the crankshaft pulley size makes.

A larger crankshaft pulley will create a higher alternator RPM; thus, causing the alternator

to produce more power at a lower engine RPM.







ALTERNATOR OUTPUT GRAPH









[Source: Balmar]







35

When the charging system fails, usually a "battery" or "alternator" warning indicator or

light will come on or the voltage (or amp) gauge will not register "good". If you increase

the engine speed and the alternator light becomes brighter, then the battery needs to be

fully recharged and tested. If the light becomes dimmer then the problem is most likely in

the charging system. Another simple charging system test is with the engine running

shine the headlights against a wall at night. If you turn the engine off and the lights get

dimmer, then the charging system is producing a higher voltage. If the light becomes

brighter, then you probably have a charging system problem. The indicator (also known

as an "idiot") light is a direct comparison between the voltage output of charging system

and the voltage output of the battery. The next test requires use of a known-to-be-good,

fully charged battery. Temporarily replace the old battery with this battery and run the

engine at 2500 RPM or more for two minutes. Depending on the load and ambient

temperature, the voltage should increase to between 13.0 and 15.1 volts during this

period. Most vehicles with good charging systems will measure between 13.8 and 14.8

volts on a warm day, depending on the battery type that the charging system was

designed for.



Some automotive charging system designers prefer lower absorption voltages, for

example 13.8 VDC, and using wet Low Maintenance (Sb/Ca) starting batteries to reduce

water consumption. This combination tends to undercharging the battery which causes

the battery to gradually loose capacity due to an accumulation of lead-sulfate. One

solution is increasing the absorption voltage output to the battery and is described by

Chris Gibson on http://www.smartgauge.co.uk/alt_mod.html. Other solutions are to use

an adjustable or "smart" voltage regulator, add resistance to the "sense" lead to the

regulator, if equipped, equalize a wet battery, or periodically fully recharge the starting

battery with an external charger to remove the sulfation. Increasing the absorption

voltage will increase water consumption in wet batteries, so the electrolyte levels will

need to be checked more often.



As in the Bosch Voltage Regulator example below, most voltage regulators are

temperature compensated to properly charge the battery under different environmental

conditions. As the ambient temperature decreases below 77° F (25° C), the charging

voltage is increased to overcome the higher battery resistance. Conversely, as the

ambient temperature increases above 77° F (25° C), the charging voltage is decreased.

Other factors affecting the charging voltage are the alternator temperature, battery's

condition, State-of-Charge (SoC), sulfation, electrical load and electrolyte purity.







VEHICLE CHARGING VOLTAGE GRAPH









36

[Source: Bosch]







If a battery terminal's voltage is below 13.0 volts with the engine running and the battery

tests good after being recharged or if you are still having problems keeping the car

battery charged, then have the charging system's output voltage and load tested. Also,

have the car's parasitic load, the electrical load with the ignition key turned off, tested.

(Please see Section 10.) A slipping alternator belt or open diode will significantly reduce

the alternator's output capacity. If the output voltage is above 15.1 volts with the ambient

temperature above freezing, if the battery's electrolyte level is frequently low, "boiling", or

if there is a "rotten egg" odor present around the battery, then the battery is being

overcharged and the vehicle's charging system should be tested.









5.2. What If My "Battery" or "Alternator" Light Is On? (Or the Gauge Is Not Showing a "Charging"

Condition?)



The "Battery" or "Alternator" light is an indication that there is a significant mismatch

between the voltage that the charging system is producing and the battery voltage. Some

vehicles use a voltmeter or current meter to indicate if the charging system is working.

The battery and charging system must work together to provide the electrical power for

the vehicle and to keep the battery recharged so it can restart the engine. The most

common causes, in the order of priority, are:



 Low electrolyte levels



 Slipping or broken alternator belt



 Corrosion between the battery posts and the battery cable terminals





37

 Faulty charging system



 Defective battery



If the electrolyte levels, alternator belt is OK and the battery terminal connections are free

from corrosion, then take your vehicle to an auto parts or battery store, and have the

battery and charging system tested (highly recommended) or use the troubleshooting

guide above. In the United States and Canada, some stores like Auto Zone, Sears, Wal-

Mart, Pep Boys, etc., will test them for free. One of the first three simple faults in the list

above has caused many a good battery to be replaced. A new battery can cause a weak

alternator or starter to fail.









5.3. What If I Cannot Keep My Battery Fully Charged and the Battery Tests OK?



The vehicle's electrical load is normally satisfied first by the charging system and then

any remaining power is used to recharge the battery. For example, if the total electrical

load is 14 amps and the charging system is producing 35 amps at 2500 RPM, then up to

11 amps will be available for recharging the battery, which will take approximately six

minutes. If the charging system is operating at say a maximum capacity of 90 amps at

5000 RPM, then the battery usually will be recharged within two minutes. Now let us

assume that the engine is idling and the charging system is only capable of producing 10

amps. Four amps from the car battery are required to make up the difference to satisfy

the 14 amp electrical load and the battery is being discharged further. This is why making

short trips, driving in stop-and-go traffic, or during bad weather when there is a heavier

electrical load, the starting battery may never get recharged and may even become

"completely" discharged.



Using the example above, let's assume that an after-market, 400 watt @ 69% efficiency

high-power audio system, 20 amp electric winch, or 276 watts of lights is installed that

adds an additional 20 amps of load. To covert power amplifier wattage into amps,

multiply the amplifier's watts by .5 to .85 (depending of the efficiency of the amplifier) and

then divide by the operating voltage. To convert winch motor or lighting power (in watts)

to amps, divide the watts by the operating voltage. With a total electrical load of 34 amps,

at RPM below 2500, the battery will never be recharged with an 90 amp system. While

the engine is running in this case, the battery must make up the deficit. The solution is to

upgrade the charging system to 125% or more of the new worst-case load. In this

example and based on stop-and-go driving habits, a high output charging system capable

of 105 amps or more would be required to keep the battery fully charged. High alternator

temperatures can further reduce the maximum output of a charging system, so cooling

and sizing based on the continuous load matters. Heat kills alternators, so Bosch, for

example, has water cooled models available.



For boat owners, Balmer recommends that alternator(s) be sized to 25% of the batteries'

total capacity for wet batteries and 35% to 40% for AGM and Gel Cell VRLA batteries.

Alternator belt sizing is also important. A single 3/8" belt will drive an alternator up to 80





38

amps, 1/2" up to 110 amps, and multiple belts for over 110 amps. Ample Power provides

an excellent Troubleshooting the Alternator System guide.









5.4. How Can I Test To Determine If Charging System Is Large Enough?



A simple test to determine if the charging system is large enough is to check the battery's

State-of-Charge after the surface charge has been removed. If the State-of-Charge is

consistently above 95%, then the charging system is fully recharging the car battery

based on your driving habits and electrical load. If is is consistently below 80%, then you

will want to consider upgrading your charging system to produce more current. There are

several possibilities to increase the capacity of your charging system to include changing

the pulley diameters, upgrading the alternator, adding a second charging system (for a

dual battery set up), replacing the voltage regulator, etc. An auto electric or alternator

rebuilding shop can assist you. If the State-of-Charge is inconsistent, the you might

consider using a temperature compensated, "smart" charger with a quick disconnector to

"top off" your battery. If consistently undercharged or overcharged, a lead-acid

battery will lose capacity and prematurely fail.









39

6. HOW DO I JUMP START MY VEHICLE?



Last Updated on December 26, 2005





Please wear glasses in the unlikely event of a car or deep cycle battery explosion and

save your eyes.



If done incorrectly, jumping a dead battery can be dangerous and financially risky. These

procedures are ONLY for vehicles are that are both negatively grounded and the electrical

system voltages are the SAME. These procedures would also apply to using emergency jump

starters. DO NOT jump a frozen battery and ALWAYS connect POSITIVE to POSITIVE and

NEGATIVE (-) to the ENGINE BLOCK or FRAME away from the dead starting battery. Reverse

this rule to disconnect. The American Automobile Association (AAA) estimates that of the 275

million vehicles that will traveling in the U.S. during the Summer of 2003, 7.4 million (or 2.7%)

will break down. Of that number, 1.3 million (or 17.7%) will require a battery jump to start their

engine. The German automobile association (ADAC) estimates that their battery related service

calls has increased from 21.7% per year in 1999 to 29.9% in 2004.



In cold weather, a good quality jumper cables (or booster cables) with eight-gauge wire is

necessary to provide enough current to the disabled vehicle to start the engine. Larger diameter

wire is better because there is less voltage loss. Please check the owner's manual for BOTH

vehicles or jump starter BEFORE attempting to jump-start. Follow the manufacturers'

procedures, for example, some vehicles should not be running during a jump-start of a disabled

one. However, starting the disabled vehicle with the good vehicle running can prevent having

both vehicles disabled. Avoid the booster cable clamps touching each other or the POSITIVE

clamp touching anything but the POSITIVE (+) post of the battery, because momentarily

touching the block or frame can short the battery and cause extensive and costly damage.



6.1. If below freezing, insure that the electrolyte is NOT frozen in the dead battery. If

frozen, do NOT jump or boost the battery if the case is cracked or until the battery has

been full thawed out, recharged, tested. When the electrolyte freezes, it expands which

can damage the plates or plate separators, which can cause the plates to warp and short

out. When the battery is frozen, the best solution is to substitute a fully charged battery

for frozen one or tow the vehicle to a heated garage. With any completely dead battery,

cell reversal can occur. Please Section 14.14. The electrolyte in a dead battery will

freeze at approximately 20°F (-6.7°C). If the battery has been sitting for several weeks

and frozen, then the battery has probably sulfated as well. Please see Sections 16 and

13 for more information. If the battery has been sitting for hours or a few days then the

problem is either an excessive parasitic load like leaving the headlights on or a faulty

charging system. Please see Sections 10 or 9, respectively.



6.2. Without the vehicles touching, turn off all accessories, heaters and lights on both

vehicles, especially an electronic appliances, such as a radio or audio system and insure

there is plenty of battery ventilation.









40

6.3. Start the vehicle with the good battery and let it run for at least two or three minutes at

medium RPM to recharge it. Check the POSITIVE (+) and NEGATIVE (-) terminal

markings on both batteries before proceeding.







JUMP STARTING









[Source: BCI]







6.4. Connect the POSITIVE booster cable (or jump starter) clamp (usually RED) to the

POSITIVE (+) terminal post on the dead battery [Step 1 in the diagram above]. Connect

the POSITIVE clamp on the other end of the booster cable to the POSITIVE (+) terminal

post on the good starting battery [Step 2]. If the POSITIVE (+) battery terminal post is not

accessible, the POSITIVE connection on the starter motor solenoid from the POSITIVE

(+) terminal post of the battery could be used.



6.5. Connect the NEGATIVE booster cable clamp (usually BLACK) to the NEGATIVE (-)

terminal on the good battery [Step 3]. Connect the NEGATIVE booster cable (or jump

starter) clamp on the other end of the jumper cable to a clean, unpainted area on the

engine block or frame on the disabled vehicle [Step 4] and at least 10 to 12 inches (25

to 30 cm) away from the battery. This arrangement is used because some sparking will

occur and you want to keep sparks as far away from the battery as practical in order to

prevent a battery explosion.







41

6.6. If using jumper cables, let the good vehicle continue to run at medium RPM for five

minutes or more to allow the dead battery to receive some recharge and to warm its

electrolyte. If there is a bad cable connection, do not wiggle the cable clamps connected

to the battery terminals because sparks will occur and a battery explosion might occur.

To check connections, first disconnect the NEGATIVE clamp from the engine block or

frame, check the other connections, and then reconnect the engine block or frame

connection last.



6.7. If using jumper cables, some vehicle manufacturers recommend that you turn off the

engine of the good vehicle to protect it's charging system prior to starting the disabled

vehicle. Check the owner's manual; otherwise, leave the engine running so you can avoid

being stranded should you not be able to restart the good vehicle.



6.8. If using jumper cables, start the disabled vehicle and allow it to run at high idle. If the

vehicle does not start the first time, recheck the connections, wait a few minutes, and try

again.



6.9. Disconnect the jumper or jump starter cables in the REVERSE order, starting with the

NEGATIVE clamp on the engine block or frame of the disabled vehicle to minimize the

possibility of an explosion. Allow the engine on the disable car to run until the engine

come to full operating temperature before driving and continue to run until you reach your

final destination, because stopping the engine might require another jump start.



6.10. As soon as possible and at room temperature, fully recharge the dead battery with an

external "smart" or "automatic" battery charger matched to the battery type, remove the

surface charge and load test the battery and charging system to determine if any latent or

permanent damage has occurred as a result of the deep discharge. This is especially

important if you had a frozen battery or jump started a sealed wet Maintenance Free

(Ca/Ca) battery. A vehicle's charging system is not designed to recharge a dead battery

and could overheat and be damaged (bad diodes or burned stator) doing so or the

battery could be under charged and loose capacity.



In the event that the jumper or jump starter cables were REVERSED and there is no power to all

or part of the vehicle, test the fusible links, fuses, circuit breakers, battery, charging system and

emissions computer and, if bad, reset or replace. Their locations and values should be shown in

the vehicle's Owner's Manual. If replacing the faulty parts do not repair the electrical system,

having it repaired by a good auto electric repair shop is highly recommended.









42

7. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY?



Last Updated on February 26, 2005





INDEX:



7.1. Battery Types



7.1.1. Wet Standard (Sb/Sb)



7.1.2. Wet Low Maintenance (Sb/Ca)



7.1.3. Wet "Maintenance Free" (Ca/Ca)



7.1.4. AGM (Absorbed Glass Mat) VRLA



7.1.5. Spiral Wound AGM (Absorbed Glass Mat) VRLA



7.1.6. Wet Marine Starting



7.1.7. Gel Cell VRLA



7.1.8. What Are the Differences Between Car, Marine Starting and Deep

Cycle Batteries?



7.1.9. What Are Dual or Multi-battery Systems?



7.2. CCA (Cold Cranking Amps)



CCA vs. Temperature Diagram



7.3. Reserve Capacity (RC) or Amp Hour (AH) Capacity



Peukert Effect



7.3.1. Is Capacity Effected By Temperature?



AH Capacity vs. Temperature Graph



7.3.2. How Do I Increase Battery Capacity?



Battery Wiring Diagrams



7.3.3. Which is Better, Two 6-volt Batteries in Series or Two 12-volt

Batteries in Parallel?



7.3.4. How Do I Increase the Voltage?

43

7.3.5. How Can I Reduce the Voltage?



7.3.6. Which Weighs More--One 12-volt or Two 6-volt Batteries?



7.3.7. Can I Mix Non-Identical Batteries?



7.4. Size



7.5. Terminals



7.6. Freshness



7.7. Warranty



7.8. Buying Tips



7.9. How Do I Size The Components For Backup AC Power?



Car battery buying strategy for use in Alaska, for example, is different than in the hotter

climates found in South Texas. In extremely cold climates, higher CCA (Cold Cranking Amp)

ratings are more important. In a hot climate, higher RC (Reserve Capacity) or AH (Ampere

Hour) ratings are more important than CCA; however, the cranking amp sizing should be based

on the coldest climate the engine is started in. Do NOT buy a new battery until it is needed

because it will sulfate sitting in storage and you will lose capacity. Below is an example of car

battery life expectancy in the United States from Interstate Batteries:









44

[Source: Interstate Batteries]



7.1. Battery Types



The two most common categories of car and deep cycle batteries are wet (also

known as "flooded", "liquid electrolyte", "vented", or "VLA" cell) and Valve

Regulated Lead-Acid (VRLA). Within the wet category, the three most common

battery types are Standard (Sb/Sb), Low Maintenance (Sb/Ca) and Maintenance

Free (Ca/Ca), which are defined in more detail below. In the VRLA category, there

are AGM (Absorbed Glass Mat), spiral wound AGM, and Gel Cell lead-acid

batteries. The one additional category for smaller (typically below 50 AH) deep

cycle batteries is SLA (Sealed Lead Acid) using AGM or Gel Cell VRLA

construction. In 2004, approximately 30% of the SLA batteries are produced in

China. All VRLA batteries are sealed with a safety pressure relief valve or plug in

case of excessive gas pressure build up due to overcharging or overheating.



When selecting a battery type, it is extremely important that you select a battery

that will MATCH the voltage output of your charging system and application. The

easiest way to accomplish this is to replace your battery with the same or

compatible type of battery that originally was installed in your vehicle or appliance.

If you change your replacement battery to another battery type, you might have to

adjust the charging voltage to prevent undercharging or overcharging that could

damage or reduce the service life of your new battery. For example, replacing an

Original Equipment Manufacturer (OEM) wet sealed "Maintenance Free" (Ca/Ca)

with a wet non-sealed Low Maintenance (Sb/Ca) battery (with filler caps) might

cause the Low-Maintenance (Sb/Ca) battery to be slightly overcharged and

consume more water. If you charge a "Maintenance Free" (Ca/Ca) battery with a

charging system or charger designed for a Low Maintenance (Sb/Ca) battery (with

45

filler caps), you could undercharge the "Maintenance Free" (Ca/Ca) battery.

Replacing any other non-Gel Cell type of battery with a Gel Cell VRLA battery

could overcharge it. When in doubt, replace with an AGM VRLA or spiral wound

AGM VRLA battery. Ventilation is required for all lead-acid batteries and good

ventilation is mandatory for wet batteries to dissipate the explosive gasses

produced during the absorption charge stage.



Deep cycle batteries are broadly divided into motive and stationary applications.

Motive applications are where the battery is discharged in operations that will

consume between 20% and 80% of the battery's capacity and then recharged

(which is considered to be one cycle). Some examples of motive (also known as

"cycling" or "traction") applications are for batteries used in recreational vehicles

(RV), motor homes, caravans, trailers, boats, wheelchairs, golf carts, solar, floor

sweepers, folk lift trucks and other electric vehicles (EV) and typically have

between 200-500 cycles per year. Stationary (also known as "float", "reserve",

"backup" or "standby") applications are where stationary batteries is used to

provide backup or standby power during loss of the primary source of power such

as uninterruptible power systems (UPS), emergency lighting systems, security

systems, telecommunications systems, etc., and typically have 2-12 cycles per

year. Generally, stationary batteries have longer service lives, more life cycles and

cost more than motive batteries. The chargers for motive and stationary deep

cycle batteries are different as well.



Non-sealed wet Standard (Sb/Sb), wet Low-Maintenance (Sb/Ca), AGM or Gel

Cell VRLA batteries with pasted, tubular or Manchester ("Manchex") positive

plates or VRLA Spiral Wound AGM batteries are recommended for motive deep

cycle applications. Non-sealed wet Standard (Sb/Sb), wet Low-Maintenance

(Sb/Ca), wet "Maintenance Free" (Ca/Ca) batteries with pasted or solid (Planté)

positive plates are recommended for stationary applications. For more information

about larger deep cycle batteries (greater than 250 AH), please see Wind & Sun's

Ultimate Deep Cycle Battery FAQ and Zen and the Art of Choosing a Deep Cycle

Battery.



Wet deep cycle batteries, such as Marine/RV, leisure and some golf cart, that use

pasted positive plates are less expensive to manufacturer and have few life cycles

and shorter service lives at 50% average Depth-of-Discharge (DoD) level than the

deep cycle batteries with solid (Planté), tubular or Manchester (or "Manchex")

positive plates. They also have significantly fewer life cycles at the 80% average

DoD level. Be aware that some starting battery manufacturers have added

handles and stud type terminals to their cheaper starting batteries and sell them as

Marine/RV deep cycle. The major disadvantage of VRLA (AGM or Gel Cell) deep

cycle batteries are their high initial cost (up to three times over the cost of a wet

Standard (Sb/Sb) batteries), but arguably can have an overall lower total cost of

ownership due to a longer service life, no "watering" and other labor costs, and

faster recharging. The total cost of ownership should be considered when buying

deep cycle batteries. There is a cost comparison for some popular wet solar deep

cycle batteries on THE SOLAR BiZ Web site at

http://www.thesolar.biz/Cost_Table_batteries.htm.





46

7.1.1. Wet Standard (Sb/Sb)



Standard or "Conventional" (Sb/Sb) non-sealed lead-acid batteries (with

filler caps) have Lead-Antimony (Sb) positive/Antimony (Sb) negative plates

and have been commercially available for almost 100 years. They have a:



 Lower initial cost



 Tolerance for a wide range of charging current (to 25% of the

battery's capacity) and voltage



 Long service live (if properly maintained)



 Increased water consumption and production of gas requiring more

ventilation



 High self-discharge rate (depending on the temperature, up to 50%-

60% per month)



 Charging losses of 15%-20% and maximum continuous discharge

rate 25% of their capacity



For these reasons, they have almost been completely replaced by wet Low

Maintenance (Ca/Sb) batteries for high temperature underhood starting

applications, but are still used for many deep cycle applications. Wet

Standard (Sb/Sb) batteries are generally the least expensive lead-acid

batteries.









7.1.2. Wet Low Maintenance (Sb/Ca)



The wet (or "flooded" cell) Low Maintenance batteries (with filler caps) have

a Lead-Antimony (Sb) positive/Calcium (Ca) negative dual alloy or hybrid

plate formulations. They have most of the same characteristics as a wet

Standard (Sb/Sb) batteries, except they can handle the high underhood

heat better when used in starting applications. Some battery manufacturers,

such as Johnson Controls, build "North" and "South" car battery versions

to make up for the differences in cold and hot climates. Some also

construct special car batteries that have a higher tolerance to heat by

changing plate or connecting strap formulations or providing for more

electrolyte. For off highway applications in trucks, recreational vehicles

(RVs), motor caravans or homes, 4x4s, vans or SUVs (Sport Utility

Vehicles), some battery manufacturers build "high vibration", "heavy duty",

"commercial", or "RV" battery versions designed to reduce the effects of

47

moderate vibration. A wet Low Maintenance (Sb/Ca) car or deep cycle

battery will typically cost a little more than a similar sized wet Standard

(Sb/Sb) battery.









7.1.3. Wet "Maintenance Free" (Ca/Ca)



Wet "Maintenance Free" batteries have a Lead-Calcium (Ca)

positive/Calcium (Ca) negative plate chemistry or formulation, for example,

Johnson Controls, General Motor's ACDelco, or East Penn. The

advantages of wet "Maintenance Free" (Ca/Ca) car and deep cycle

batteries over wet Low Maintenance (Sb/Ca) are:



 Less preventive maintenance due to less water loss



 Greater overcharge resistance



 Reduced terminal corrosion and ventilation



 Up to 400% less self discharge



 Less risk to consumers because there is less to service



However, they are more prone to terminal leakage due to over-tightening,

incorrect terminal length, or vibration from to short battery cables. They are

also more susceptible to deep discharge ("dead" or "flat" battery) failures

due to increased shedding of active plate material and development of a

barrier layer between the active plate material and the grid metal. If a wet

"Maintenance Free" (Ca/Ca) battery is sealed, distilled water can not be

added when required. For that reason, in hot climates, using non-sealed

wet batteries (with filler caps), so you can add distilled water, is highly

encouraged. For passenger compartment or trunk battery locations, using a

sealed AGM VRLA battery is recommended. Wet "Maintenance Free"

(Ca/Ca) batteries are generally little more expensive than wet Low

Maintenance (Sb/Ca) batteries.









7.1.4. AGM (Absorbed Glass Mat)VRLA



Sealed Absorbed Glass Mat (AGM) VRLA car and deep cycle batteries

(also know as "starved electrolyte" or "dry") have a very fine fiber Boron-

Silicate glass mat between their plates. They have all of the advantages of

the "Maintenance Free" (Ca/Ca) batteries plus:



 Safer (due the hydrogen gas recombination during charging)



48

 Do not require water



 Lower self-discharge rate (typically 1%-2% per month)



 Longer service life



 Higher resistance to vibration



 Lower deep discharge failure



 Higher bulk charge acceptance rate (which means up to a 15%

shorter recharge time and reduced cost)



 Lower tolerance for heat (they will lose half of their service life for

every increase of 15° F (8.3° C) over 80° F (26.7° C)



 Do not require special hazardous shipping and can be used in

saltwater applications



 Spill proof and can be mounted in virtually any position (because

they are sealed)



 Charging losses of 4% and maximum continuous discharge rate 33%

of their capacity



 Can be used inside a semi-enclosed area, like the passenger

compartment or trunk



 Greater terminal corrosion resistance



 Less charging voltage tolerance



 Not subject to sulfation from electrolyte stratification or water loss



Relocating the vehicle's starting battery to the passenger compartment or

trunk is becoming more popular because vehicle manufacturers want to

extend their "bumper-to-bumper" warranty periods, to avoid underhood

temperature extremes, to provide more weight in the rear, or to save

underhood space. Use a vented wet battery or GRT (Recombinant Gas

Technology) AGM or Gel Cell VRLA battery. GRT simply means that 90%

or more of the gasses are recombined back into water during recharging

and contained within each cell and special venting is not required. AGM

VRLA batteries are more expensive than wet "Maintenance Free" (Ca/Ca)

batteries. Some AGM batteries, for example Concorde, can be equalized.

They will accept all the power that a charging system will produce. This

means if you are using an alternator sized at 25% (or less) of the capacity

of a deep cycle battery bank, it possible to overheat an air cooled

alternator and burn it up during a long bulk charging phase. For large

capacity deep cycle battery banks, using a high output alternator, voltage

regulator with an alternator temperature sensor or water cooled alternator is





49

highly recommended. A thermally protected alternator should not exceed

33% of the capacity of the battery bank being charged.



You can expect AGM VRLA starting batteries to the $80 to $100 range as

more competition occurs. Examples of sealed AGM VRLA batteries are

Concorde's Lifeline, EnerSys' Odyssey, East Penn, or New Castle. An AGM

battery can normally replace a wet Low Maintenance (Sb/Ca) or wet

"Maintenance Free" (Ca/Ca) battery, but a wet Low Maintenance (Sb/Ca)

battery normally cannot replace an AGM VRLA battery without adjusting the

charging voltages. Expect to see 36-volt AGM starting batteries with 14/42-

volt dual or 42-volt electrical systems offered by some of the premium car

manufacturers starting in the 2003 model year. In the near term, expect to

see more sealed AGM batteries replacing wet Low Maintenance and wet

"Maintenance Free" lead-acid batteries. In the longer term, NiHM and

Lithium Ion (LiIon) batteries will used in hybrid automotive applications,

which might eventually be replaced by fuel cells in the next 10-20 years.









7.1.5. Spiral Wound AGM (Absorbed Glass Mat)VRLA



For excessive vibration applications, in off-road operation, or extreme

conditions, it is best to use a spiral wound AGM VRLA (Valve Regulated

Lead-Acid) car or deep cycle battery because there is no shedding of active

plate material since the plates are immobilized. In addition, they use GRT

(Recombinant Gas Technology) and have all of the characteristics of the

AGM VRLA batteries plus:



 Smaller



 Recharges faster reducing charging cost



 Wider absorption and float charging voltage windows



 Withstand heat better



 Charging losses of 4% and maximum continuous discharge rate 33%

of their capacity



Examples of spiral wound VRLA AGM batteries are Johnson Controls'

Optima, Exide's Select Orbital or Maxxima, or EnerSys' Cyclon. Typically

spiral wound AGM car batteries cost between $90 and $150 and deep cycle

versions cost more.



SPIRAL WOUND AGM BATTERY









50

[Source: Optima]









7.1.6. Wet Marine Starting



A wet "Dual" or Marine Starting battery is a compromise between a car and

deep cycle battery that is specially designed for high vibration in marine

applications and generally are more expensive thatn their car battery

counterpart. A Marine Starting battery can have wet Standard (Sb/Sb), wet

Low Maintenance (Sb/Ca), wet "Maintenance Free" (Ca/Ca) or AGM VRLA

plate formulations. But, please beware of Marine Starting and deep cycle

batteries that are cheap, because they are often car batteries with handles

and stud or combination terminals. A deep cycle or "Dual Marine Starting"

battery will work as a starting battery if it can produce enough current to

start the engine. Good ventilation is required for all wet (or "flooded")

deep cycle batteries to dissipate the gasses produced during

charging. For saltwater applications, sealed AGM (or Gel Cell) should

be only used to prevent the formation of DEADLY chlorine gas when

battery electrolyte is mixed with saltwater.









7.1.7. Gel Cell VRLA



Sealed Gel Cell VRLA (Valve Regulated Lead-Acid) deep cycle batteries

use GRT (Recombinant Gas Technology) and use a thickening agent like

fumed silica gel to immobile the electrolyte instead of a liquid electrolyte like

the wet batteries. They have a lot of the same advantages of AGM

batteries. When comparing Gel Cell to AGM and Spiral Wound AGM

batteries, Gel Cells will typically:



 Greater ability to withstand a deep discharge, but not temperatures

over 100°F (37.8° C) because of the possibility of "thermal runaway"



 10 to 15 cycle preconditioning or "break-in" period



 Less Cold Cranking Amps



 80% of the capacity of a similar sized AGM battery and physically

larger



 Slower recharging times





51

 Intolerant of incorrect charging voltages which require special gel cell

chargers



 Lower capacity in cold temperatures



 Up to 20% more life cycles



 Most expensive because it costs more to manufacture



 Subject to loss of capacity due to voids between the plates when

overcharged



 Charging losses of 4% and maximum continuous discharge rate 25%

of their capacity



The ideal ambient temperature for a Gel Cell battery is 72° F (22.2° C).

Examples of Gel Cell batteries are Sonnenschein, East Penn, MK, Exide,

etc.



For some considerations of replacing flooded batteries with Gel Cell or

AGM VRLA batteries, please read David Eidell's IMPORTANT NOTE

ABOUT THE SUITABILITY OF ABSORPTIVE GLASS MAT (AGM) AND

GELLED ELECTROLYTE BATTERIES IN RV'S or Collyn Rivers'

ABSORBED GLASS MAT BATTERIES. For a more detailed comparison,

read an article written by Constian von Wentzel, Comparing Marine Battery

Technologies.









7.1.8. What Are the Differences Between Car, Marine Starting and Deep Cycle Batteries?



Car batteries are specially designed with thinner (.04 inch or 1.02 mm) and

more porous plates for a greater surface area to order produce the high

amps required to start an engine. They are engineered for up to 5,000

shallow (to 3%) discharges, which is over four engine starts per day.

Starting batteries should NOT be discharged below 90% State-of-Charge.

They use sponge lead and expanded metal grids rather than solid lead.

Marine starting batteries are a comprise between a car and deep cycle

battery and are designed for starting and prolonged discharges at lower

amperage that typically consumes between 20% and 50% of the battery's

capacity. Motive and stationary deep cycle batteries have much thicker (up

to .25 inch or 6.35 mm) plates, thicker grids, more lead, and weight more

than car batteries the same size. They are normally discharged between

20% and 80% at lower amperage. Deep cycle batteries will typically

outlast two to ten car batteries in a deep cycle application.



Can a deep cycle battery be used as a starting battery?



Five things to consider in using a deep cycle battery as a starting battery.

52

 Is it the same battery type as your OEM starting battery? This is so

that your vehicle's charging system will keep it fully charged. Please

see Section 7.1 for more on battery types and Section 4 for testing

the State-of-Charge (SoC) of the battery.



 Will the battery produce enough current to start the engine in the

coldest temperatures that you start your engine in?



 Will it fit and the battery cables connect to the correct battery posts?



 Can you afford to get stuck some cold morning until you can jump

start your vehicle if it does not have the capacity to start you engine?



 Is the battery fresh and in good condition? If the battery has been

sitting around for weeks or months without a charge is has probably

has sulfated? If the battery has sulfated, then please see Section 16.



If the answer to these questions is yes, then it will work. However, it might

crank the engine slower or not last as long as a starting battery for this

application, due of the high under hood temperatures and shallower

discharges. There have been other examples where a wet motive deep

cycle battery has lasted over ten years. Fully recharge the deep cycle

battery with an external charger first and have it tested at an auto parts or

battery store. If good, then try it and monitor the SoC and electrolyte levels

for the the first few months for proper charging. If the State-of-Charge is

continuously low, the battery is being uncharged and sulfate will gradually

build up; thus, reducing the capacity of the battery and it will prematurely

fail. If it is using a lot of water, then it is being overcharging and it can

prematurely fail.









7.1.9. What Are Dual or Multi-battery Systems?



For RVs, motor homes, caravans, boats, and other large vehicles, both car

and deep cycle batteries are often used. A car battery is normally used to

start the engine and motive deep cycle (or leisure) batteries that are the

same battery type (plate chemistry) as the car battery are used to power the

electrical accessories. The batteries are connected to a Schottky diode

isolator (or combiner), dual output alternator, isolation relay or A/B switch to

keep the starting battery from becoming discharged when using the deep

cycle batteries. When the charging system is running, the batteries are

automatically recharged (except with the manual relay or A/B switch) with

most of the current flowing to the battery with the lowest State-of-Charge.

Isolator sizing is important and should be larger than the combined current

sources on each side of the isolator. For example, if a diode isolator is used

with a 40 amp shore power battery charger and a 100 amp alternator, then

the diode rating should be at least 140 amps. If a relay or A/B switch is

used and the charger is 100 amps, but there is a load of 300 amps, then the

53

isolator need to be rated at the larger of the two or 300 amps or more. The

wiring with fuses also needs to be rated to carry this much current with a

5% or less voltage drop.









Ralph Scheidler at Sure Power has written an excellent, easy to

understand, free e-booklet, Introduction to Batteries and Charging Systems,

about multi-battery applications. It is available online at

http://www.surepower.com/pdf/ebr_int.pdf. A common deep cycle

application in recreational vehicles is using a DC to AC inverter, which is

used to convert 12 VDC to 120 (or 240) VAC power. It takes between 12

and 14 amps of 12-volt DC power to make one amp (or 120 watts) of 120

VAC power (or one-half amp or 120 watts of 240 VAC power), so deep

cycle batteries or vehicle charging systems should be used to power

inverters and NOT starting batteries. Some multi-battery systems can get

extremely complex.



Some of the following risks are undertaken when a discharged deep cycle

battery (or bank) is connected in parallel to the starting battery without using

a diode isolator:



 If a discharged deep cycle battery (or bank) is connected to a

charged starting battery in parallel, a large current could flow from

the starting battery to the deep cycle battery in an attempt to

equalize the voltage. Overtime, deeply discharging the starting

battery could prematurely kill it. This can discharge the starting

battery to the point that the engine can not be started.



 If the wiring or contacts of the isolation relay or switch are not heavy

enough to carry the current, damage could occur.



 If 4% or more concentration of hydrogen is present, an

explosion could occur due to the arc created by the relay or

switch closure.



54

 If the charging system has insufficient capacity, a large deep cycle

battery (or bank), especially a AGM VRLA, could accept all the

output of the charging system and overheat the alternator causing it

to fail or not fully recharge the starting battery.



 Either the deep cycle battery (or bank) is undercharged or the

starting battery will be overcharged.



Diode isolation systems, unless voltage compensated, lose between .6 and

1.6 volts across each diode. There is also loss in wring that will reduce the

charging voltage to the battery. Regardless of what isolation method is

used, if at all possible the correct battery manufacturer's temperature

compensated charging voltages need to be applied directly across the

respective battery terminals to optimize the battery's capacity and overall

service life. This can be accomplished in several different ways depending

on the charging system. For example, if the voltage regulator has a sense

wire (if equipped), it can be connected to the output of the diode isolator or

positive battery terminal or the internal voltage regulator can be replaced

with an adjustable or a "smart" voltage regulator. If the voltages are not

correct, then battery under or overcharging can occur, so it is important to

apply the correct charging voltages for longer battery service life. If the

deep cycle battery bank is located with a living or passenger area, using

AGM or Gel Cell VRLA batteries are highly recommended for safety

reasons.









7.2. CCA (Cold Cranking Amps)



If the battery is to used in a starting application, Cold Cranking Amps (CCA) is the

second most important consideration; otherwise, for non-starting deep cycle

applications, please skip this section and go to Section 7.3. Reserve Capacity

(RC) or Amp Hour (AH) Capacity. The battery's CCA rating should meet or

exceed, your vehicle's OEM cold cranking requirement, for your climate. BCI's

definition of CCA is the discharge load measured in amps that a new, fully charged

battery, operating at 0° F (-17.8° C), can deliver for 30 seconds and while

maintaining the voltage above 7.2 volts. car and Marine Starting batteries are

sometimes advertised by their CA (Cranking Performance Amps) measured at 32°

F (0° C), MCA (Marine Cranking Amps) measured at 32° F (0° C), or HCA (Hot

Cranking Amps) measured at 80° F (26.7° C). These measurements are not the

same as CCA. Do not be misled by the higher CA, MCA or HCA ratings. To

convert CA or MCA to CCA, multiply the CA or MCA by 0.8. To convert HCA to

CCA, multiply HCA by 0.69. The British and International Electrotechnical

Commision's definition of CCA are cranking for 180 seconds and down to 8.4 volts

at 0° F (-17.8° C) and for 60 seconds and down to 8.4 volts at 0° F, (-17.8° C),

respectively.







55

To start a four cylinder gasoline engine, you will need approximately 600-700

CCA; six cylinder gasoline engine, 700-800 CCA; eight cylinder gasoline engine,

750-850 CCA; three cylinder diesel engine, 600-700 CCA; four cylinder diesel

engine, 700-800 CCA; and eight cylinder diesel engine, 800-1200 CCA. Bruce

Bowling and Al Grippo have written a very handy Battery Cold-Cranking Amp

Estimation calculator which can be found at http://www.bgsoflex.com/cca.html. To

convert CCA, a SAE (Society of Automotive Engineers) standard, to an EN (now

known as ETN), IEC, DIN or JIS standard, please refer to the Conversion Table at

http://www.midtronics.com/manuals/power_sensor105_manual.pdf from

Midtronics.



In hot climates, buying car or marine starting batteries with double or triple the

cold cranking amps that exceeds your starting requirement is a waste of money

because the extra amps will not be used. A starter motor will only demand what it

needs to operate. However, in extremely cold climates a higher CCA rating is

better, due to increased power required to crank a sluggish engine and the

inefficiency of a cold car battery and the demand is greater. As car batteries age,

they are also less capable of producing as much CCA as when they were new.

According to the BCI (Battery Council International), diesel engines require 220%

to 300% more current than their gasoline counterparts and winter starting requires

140% to 170% more current than the summer. These increased requirements are

accounted for in the OEM (Original Equipment Manufacturer) CCA

recommendation.







CCA vs. TEMPERATURE









[Source: Exide]



56

If more CCA capacity is required, two identical 12-volt starting batteries can be

connected in parallel or two identical larger CCA 6-volt starting batteries can be

connected in series. Please refer to the diagrams in Section 7.3 below for more

information about connecting batteries in parallel or series. If you connect two 12-

volt batteries in parallel and they are identical in type, age and capacity, you can

potentially double your original CCA capacity. If you connect two that are not the

same type or capacity, you will either overcharge the smaller (or older) of the two

or you will undercharge the larger (or newer) of the two.









7.3. Reserve Capacity (RC) or Amp Hour (AH) Capacity



For car batteries, an equally important consideration to CCA is the Reserve

Capacity (RC) or Amp Hour (AH) Capacity ratings because of the effects of

increased parasitic (ignition key off) loads while long term parking, power demands

during short trips and emergencies. RC is the number of minutes a fully charged

battery at 80° F (26.7° C) can be discharged at a constant 25 amps until the

voltage falls below 10.5 volts. European and Asian starting and deep cycle

batteries are usually rated in Amp Hours (AH). To convert RC to AH (or AH to RC),

check the battery manufacturer's specifications. More RC is better in every case.

In a hot climate, if your car has a 360 OEM cold cranking amps requirement, then

a 400 CCA rated battery with 120 minutes of RC and more electrolyte for cooling

would be more desirable than one with 600 CCA with 90 minutes of RC. There is

also a relationship between the weight of the battery and the amount of RC (or

AH). The heavier the battery, the more lead is has and potentially a longer service

life.



For deep cycle batteries, an important consideration is that the Ampere-Hour (AH)

rating will meet or exceed the requirements based on your application, Peukert

Effect and how much weight you can carry. Most deep cycle batteries are

normally rated in number of hours it take to discharge a fully charged battery to

10.5 volts in 20 hours at 80° F (26.7° C), denoted as "C/20". Discharge rates of

100 hours (C/100), 10 hours (C/10), 8 hours (C/8) or 6 hours (C/6) are also

common ratings. (Please see Section 9) for more information on charging and

chargers. Within a BCI Group Size, the battery with higher AH (or RC) will tend to

larger in physical size, have longer lives and weigh more because of thicker plates

and more lead.









57

PEUKERT EFFECT

The higher the discharge rate (or fewer hours the battery is fully discharged in), the lower

the capacity due to the Peukert Effect or "the shrinking battery effect" and to the internal

resistance of the battery. Good examples of the Peukert Effect on deep cycle battery

capacities at various discharge rates can be found at http://www.usbattery.com/ on their

capacity specifications page. The actual formula is T=C/IN where N is the Peukert

Number used for the specific battery to more accurately calculate the discharge time. The

Peukert Number generally is in a range of 1.05 to 1.4, with 1.05 the best performing

battery due to less internal resistance. A Peukert Number calculator and some specific

examples of batteries can be found on Eve's Battery Page at

http://www.geocities.com/CapeCanaveral/Lab/8679/battery.html.The effects are shown in

Constantin von Wentzel's graph below. A good analogy on the Peukert Effect and be

found at Ample Power on http://www.amplepower.com/pwrnews/beer/. Another Peukert

calculator is included on http://home.hetnet.nl/~marcellebarion/epeukert.html.









[Source: How Lead Acid Batteries Work]









Normally the best buy will be the heaviest battery that best suites your

application, physical size requirements and that has the lowest cost (including

maintenance) for the total amount of power it will produce over it's service life.

Larger is better!

58

7.3.1. Is Capacity Effected By Temperature?



Temperature matters! The following graph from Concorde shows the

effects of temperature on the amp hour capacity on their AGM battery:









PERCENT CAPACITY vs. TEMPERATURE









[Source: Concorde]









59

7.3.2. How Do I Increase Battery Capacity?



If more amp hours (AH) or Reserve Capacity (RC) are required, there are

normally three ways to accomplish this:



7.3.2.1. Two (or more) identical 12-volt batteries can be connected

in parallel. If you connect two 12-volt batteries in parallel and they

are identical in type, age and capacity, you can more than double

you original capacity due to the Peukert Effect. If you connect two

that are not the same type or capacity, you will either overcharge the

smaller of the two, or you will under charge the larger of the two.

Please take special note of the POSITIVE (+) connection and

NEGATIVE (-) connection to the discharging destination (load) or

charging source(s) and limit the number of batteries (or strings of

batteries) in parallel to four.









12 Volts Parallel



[Source: Yacht Outfitting]







7.3.2.2. Two identical larger capacity six-volt batteries can be

connected in series (POSITIVE (+) terminal of Battery One to the

NEGATIVE (-) terminal of Battery Two).









12 Volts Series



[Source: Yacht Outfitting]







60

7.3.2.3. Two identical larger capacity six-volt batteries can be

connected in series (POSITIVE (+) terminal of Battery One to the

NEGATIVE (-) terminal of Battery Two) to make a "12-volt battery".

Two (or more) identical "12-volt batteries" can be connected in

parallel. The combination is referred to as a series-parallel

connection. Please take special note of the POSITIVE (+) connection

and NEGATIVE (-) connection to the load or charger and limit the

number of batteries (or strings of batteries) in parallel to four.









12 Volts Series-Parallel



[Source: Yacht Outfitting]







Additional information on deep cycle battery bank sizing can be found at

http://www.glacierbay.com/ in an article written by the folks at Glacier Bay

Refrigeration or by Constian von Wentzel at

http://www.vonwentzel.net/Battery/02.Size/index.html. Information of

splitting battery banks can be found in Chris Gibson's article on

http://www.smartgauge.co.uk/splitting.html.



When connected as exactly shown in the diagrams, the batteries will

discharge and charge equally. Between the batteries, cable lengths should

be an equal length, short as possible and sized large enough to prevent

significant voltage drop of 0.075 volts (75 millivolts) per 100 amps or less in

the cables and connectors. Battery cables to the charger or inverter should

be an equal length so the batteries will charge or discharge evenly. What is

important is that the battery manufacturer's recommended charging

voltages are being applied directly across the battery's terminals from

the charging source. Using an adjustable Low Voltage Disconnect set to a

minimum of 10.5 VDC (12.0 VDC is better) will insure a higher average

Depth-of-Discharge and will protect electrical and electronic appliances and

the batteries from damage from a real deep discharge and cell reversal.









61

7.3.3. Which is Better, Two 6-volt Batteries in Series or Two 12-volt Batteries in Parallel?



Some battery experts believe that batteries in series are easier to discharge

or charge because the same amount of current is applied to each cell and

are a little more reliable. Other battery experts believe that batteries in

parallel are better because they require less space, will have more capacity

due to the Peukert Effect and if a cell should fail, the bad battery can be

disconnected and the other one can continued to be used. For additional

information on this discussion, please read Battery Configuration: Parallel

or Series? published by Sierra Nevada Airstreams.









7.3.4. How Do I Increase the Voltage?



If more voltage is need, connect identical batteries in series in the following

manner:









12 Volts Series









24 Volts Series



[Source: Yacht Outfitting]







Two identical 6-volt batteries can be connected in series to produce 12-

volts. Two identical 12-volt batteries or three identical 8-volt batteries can

be connected in series to produce 24-volts. Three identical 12-volt

batteries connected in series or six identical six-volt batteries will produce

62

36-volts and so on. Please note that the total amp hour capacity remains

the same. Other voltage combinations are possible, but the battery type and

amp hour capacity of each batteries should be the same because uneven

discharging can cause charging problems.



You could also use a DC-to-DC Converter to produce different or constant

DC voltage. A common problem is powering a laptop computer or other

appliance requiring more than 14 VDC from a 12-volt battery. Using an

efficient DC-to-DC Converter is automatic and eliminates the problems

associated with uneven multi-battery discharges and recharges.









7.3.5. How Can I Reduce the Voltage?



"Half-tapping" two batteries in series can be used to produce a source with

half of the voltage and three batteries for one third and two thirds the

voltage. For example and using the diagram below, let's assume that two

identical 12-volt batteries are used in series to power a 24-volt trolling

motor and there is a requirement to power 12-volt lights or electronic

equipment. The 12-volt electrical appliances can be connected to the 12-

volt batteries as long the 12-volt electrical loads are equally divided

between the two 12-volt batteries, so the loads are balanced and fused.

[The negative connection for Load 1 must be isolated from "ground"

because it will place a dead short in the Battery for Load 2.] If the batteries

are discharged unequally, recharging the batteries with a single bank

charger (a 24-volt charger in this example) will cause one of the batteries to

be either undercharged or the other to be overcharged. This significantly

reduces the battery's service life. A better solution is to use a 24-volt to 12-

volt DC-to-DC Converter or a separate 12-volt charging system and battery

to produce 12-volts because an unbalanced load will not occur on the

batteries. If discharging the batteries unevenly or use of non-identical

batteries has to occur, then use an isolated multi-bank charger, single bank

charge with an external diode isolator (adjusted for the voltage loss), or

combiner to recharge the batteries at the same time.



Below are examples of wiring diagrams of "half tapped" 12-volt, 24-volt, and

36-volt battery banks.









63

64

65

7.3.6. Which Weighs More--One 12-volt or Two 6-volt Batteries?



Of equal amp hour capacity, a single 12-volt battery will weigh

approximately 10% less than two six-volt batteries connected in series due

to the additional case material and the battery connecting cable. But, the

two six-volt batteries can be split a part and each battery weighs

approximately half of the weight of the 12-volt battery.









7.3.7. Can I Mix Non-Identical Batteries?



To prevent charging problems when connecting batteries in series, parallel,

or series-parallel, do not mix old and new batteries or ones of different

capacities or types. Mixing old batteries with new batteries is like

mixing old milk with new milk--soon you have nothing but old milk.

The reason is because you will either undercharge the larger (or newest) of

the batteries or overcharge the smaller (or oldest) of the batteries. If

66

discharging the batteries unevenly or use of non-identical batteries has to

occur, then use an isolated multi-bank charger, single bank charge with an

external diode isolator (adjusted for the voltage loss), or combiner to

recharge the batteries at the same time.









7.4. Size



In North America, manufacturers build their batteries to an adopted Battery

Council International (BCI) Group Size Number (U1, 24, 27, 31, 34, 35, 65, 75, 78,

8D, GC, L-16, etc.) standard. These specifications, which are based on the

physical case size, terminal placement, type and polarity. In Europe, the ETN

(European Type Numbering) standard has replaced the older EN, IKC, Italian CEI,

and German DIN standards. In Asia, the Japanese JIS standard is commonly

used. The OEM battery number is a good starting place to determine the

replacement battery. Within a size, the CCA and RC ratings, warranty and battery

type will vary within models of the same brand or from brand to brand. Batteries

are generally sold by model or series, so the size numbers will vary for the same

price. For the same price, potentially a physically larger battery with more CCA or

RC (or AH) can be purchased than the battery being replaced. For example, a

34/78 group might replace a smaller 26/70 group and give an additional 30

minutes of RC. If you buy a physically larger battery, be sure that the replacement

battery will fit, the cables will connect to the correct terminals, and that the

terminals will NOT touch metal surfaces such as the hood when it is closed.



The battery manufacturers publish application Selection Guides that contain OEM

cold cranking amperage requirements and group number replacement

recommendations by make, model and year of car, battery size, and CCA and RC

(or Amp Hour) specifications. You can also find the BCI size information online at

http://www.rtpnet.org/~teaa/bcigroup.html or in some of the Selection Guides in

the Battery Manufacturers and Private Labels List found at

http://www.batteryfaq.org. Manufacturers might not build or the store might not

carry all the battery sizes. To reduce inventory costs, dual terminal "universal"

batteries that will replace several group sizes are becoming more popular and fit

75% or more of cars on the road today.









7.5. Terminals



There are six types of common battery terminals: SAE Post, GM Side, "L", Stud,

combination SAE and Stud, and combination SAE Post and GM Side. For

automotive applications, the SAE Post is the most popular, followed by GM Side,

then the combination "dual" SAE Post and GM Side. "L" terminal is used on some

67

European cars, motorcycles, lawn and garden equipment, snowmobiles, and other

light duty vehicles. Stud terminals are used on heavy duty and deep cycle

batteries. The POSITIVE (+) SAE terminal post is slightly larger, 1/16 inch (1.6

mm), than the NEGATIVE (-) post. Terminal types, locations and polarity will vary.

There are adapters available that will you allow to connect cables with "GM" style

side terminals to batteries with top post terminals or visa versa.









[Source: BCI]







Battery manufacturers or distributors will often "private label" their batteries for car

manufacturers, large chain stores or export. An alphabetical list of most of the

largest battery manufacturers/distributors, their Web addresses, telephone

numbers and some of their brand names, trademarks and private labels can found

in the Battery Manufacturers & Private Labels List at http://www.batteryfaq.org/.

Ownership, branding, Web addresses and telephone numbers will sometimes

change.









7.6. Freshness

68

Lead-acid batteries are perishable and sulfate in storage due to their natural self

discharge. Please see Section 16 for more information on sulfation.



Determining the "freshness" of a battery is sometimes difficult. Unless it has been

periodically recharged or "dry charged", NEVER buy a wet Standard (Sb/Sb) or

Low Maintenance (Sb/Ca) battery that is MORE than three months old or a wet

Maintenance Free (Ca/Ca) battery that is MORE than six months old. Dry charged

batteries are shipped without electrolyte, but usually have "sell by" dates of one to

three years. Depending on the temperature, AGM and Gel Cell batteries that can

be stored six to 18 months before the State-of-Charge drops below 80%. Please

see Section 16. for more information on sulfation. Dealers will place their older

batteries in storage racks so they will sell first and they do not have to maintain

them. The fresher batteries can be found in the rear of the battery rack or in a

storage room. For a wet battery, the date of formation is often stamped on the

case or printed on a sticker. If at all possible, have a new battery tested, and

recharged if necessary, before the battery leaves the store. This can save a lot of

time and frustration if the new battery is sulfated or has a manufacturing defect.



Some of the manufacturer's formation date coding techniques are as follows:



7.6.1. Delphi (ACDelco) and some Sears DieHard



Dates are stamped on the cover near one post. The first number is the

year. The second character is the month A-M, skipping I. The last two

characters indicate geographic areas. For example, 0BN3=2000 February.









[Source: Interstate Batteries]







7.6.2. Douglas



Douglas uses the letters of their name to indicate the year of manufacture

and the digits 1-12 for the month, D=1994 O=1995 U=1996 G=1997

L=1998 A=1999 S=2000. For example, S02=2000 Feb.



7.6.3. East Penn, Exide (Champion), Johnson Controls Inc., Interstate, Mopar (Chrysler)

and some Sears DieHard)







69

Usually on a sticker or hot-stamped on the side of the case. A=January,

B=February, and the letter I is skipped. The number next to the letter is the

year of shipment. For example, B0=Feb 2000.









[Source: Interstate Batteries]







7.6.4. Exide (some Sears non-Gold DieHards)



The fourth or fifth character is the month. The following numeric character is

the year. A-M skipping I. For example, RO8B0B=February 2000.









[Source: Interstate Batteries]







7.6.5. Optima



The first character is the year. The following three numeric characters are

the days of the year. For example, 3123=3 May 2003.



7.6.6. Trojan



The date code on the negative post is stamped as the battery comes off of

the finishing line, ready to ship out or go into stock. The code that is

stamped is usually one month ahead. Therefore, a battery that comes out in

March will carry an April date code. The code on the positive post is the

manufacturing date that indicates when the battery was physically built but

before the addition of any electrolyte. The letter is the month (A=Jan,

B=Feb, C=March, etc.) and the number is the actual date. So "K26" means

that the battery was ready for electrolyte filling and the first forming charge



70

was on November 26th. Since the negative post shows A2 (January 2002),

the manufacturing year has to be 2001.



7.6.7. Concorde



The activation date is on an orange sticker the shipping carton or email

Concorde Customer Service with the serial number of the battery.



7.6.8. Rolls and Surrette



The four digit date code represents the day of the week (first digit), week of

the year (middle two digits) and the year (last digit). For example, April 4,

2003 would have 4143 as a date code. The date code is stamped into the

front edge of the cover of the battery.



If you cannot determine the date code, ask the dealer or contact the manufacturer.

Because of permanent sulfation due to self discharge, fresher is definitely better

and does matter.









7.7. Warranty



Battery warranties are not necessarily indicative of the quality or service life.

Some dealers will prorate warranties based on the list price of the bad battery, so

if a battery failed half way or more through its warranty period, buying a new

battery outright might cost you less than paying the difference under a pro rated

warranty. The exception to this are the free replacement warranties. They

represent the risk that the manufacturer is willing to assume. A longer free

replacement warranty period is generally better depending on the cost of the

battery.









7.8. Buying Tips



The following are some tips for consumers for buying car, motorcycle, truck,

marine and recreational vehicle starting and deep cycle batteries. Before you buy

a replacement battery, you should fully charge your old battery, remove the

surface charge and test it. You could have a faulty charging system, loose

alternator belt or corroded terminals.



7.8.1. Size matters!



Purchasing a battery has become much easier because most of the battery

and vehicle manufacturers have adopted the BCI Group Number, European

Type Number (ETN) or JIS as a standard for the battery's voltage, physical

71

size, and terminal type and location. Web based Battery Selectors

published by battery manufacturers or distributors can make the task even

easier. They contain the vehicle's minimum cold cranking amps (CCA)

requirement and battery size replacement recommendations by make,

model and year of manufacturer.



7.8.2. Pick the battery type that matches your charging system.



For starting an engine, using a car or starting battery is normally a better

choice than a deep cycle battery because it is specifically designed for

shallow (1%-3%) discharges. The battery type MUST match the vehicle's

charging system or the new battery or charging system could be damaged.

The easiest way to accomplish this is to replace your battery with the same

or compatible type of battery that was originally installed by the vehicle's

manufacturer. The exception to this is in hot climates, using a non-sealed

wet car battery (with filler caps) is highly encouraged because lost water

can be easily replaced. For batteries with side terminals commonly found in

General Motors vehicles, check the terminal bolt length and do not over-

tighten because you might crack the battery case and cause a leak.



For a deep cycle application, using a deep cycle battery is much better

alternative than using a starting battery because the deep cycle battery will

have a much longer service life when deeply discharged and the plates are

thicker.



7.8.3. For car batteries, select the battery with CCA (Cold Cranking Amps) that will meet

or exceed the vehicle manufacturer's recommendation.



Do not substitute CA (Cranking Performance Amps), MCA (Marine

Cranking Amps), or HCA (Hot Cranking Amps) for CCA. In hot climates,

buying batteries with double or triple the cranking amps that exceeds the

starting requirement is a waste of money, unless starting batteries used in

extremely cold climates due to increased power required to crank a

sluggish engine and the inefficiency of a cold battery. James W. Douglas'

recommendation in his February 2000 article, Battery Selection--A

Consumers Guide, in The Battery Man magazine, is:



"The sleek, aerodynamic designs have low cooling airflow through

the engine compartment and that small in stature battery with high

cold crank [amps] will have many very thin lead plates just to get the

necessary surface area to make that big cold crank number. It will

have the lower volume of electrolyte to provide the cooling necessary

for long life and the greater capacity to run the [electrical] systems on

the car. All of those thin plates will corrode away and fail long before

expected putting the high performance battery's life below that of the

lower CCA rated battery with the lower cost. Your best rule-of-thumb

is, if it meets the OEM (Original Equipment Manufacturers)

recommendation, buy it. Look for the highest reserve capacity [RC]

battery at the correct CCA (Cold Cranking Amps)."



72

7.8.4. More Reserve Capacity (RC) or Amp Hours (AH) is a good thing.



Greater RC or AH is better because of the effects of increased parasitic

(ignition key off) loads and normal battery self discharge while the vehicle is

not being used or in storage and the demands of stop-and-go driving. Amp

Hour (AH) ratings are normally used to describe the capacity of deep cycle

and European car (starting) batteries. When comparing AH specifications,

use the same discharge rates, expressed in hours. The most common is

the 20 hour rate which is expressed as "C/20". A heavier battery has more

lead and is normally better choice.



Batteries are generally sold by model or series, so the battery sizes can

vary for the same price. This means that for the same price, potentially a

larger battery with more RC or AH than be purchased than the battery being

replaced. If a physically larger battery is bought, be sure that the

replacement battery will fit, the cables will connect to the correct terminals,

and that the terminals will NOT touch metal surfaces such as a closed hood

(or bonnet).



7.8.5. Batteries are perishable, so buy the FRESHEST available.



Unless a battery has been periodically recharged, never buy a non-sealed

wet Standard (Sb/Sb) or Low Maintenance (Sb/Ca) battery that is more

than three months old, a sealed wet Maintenance Free (Ca/Ca) battery that

is more than six months old, or sealed AGM or Gel Cell battery that is over

12 months old, because it has started to sulfate. "Dry charged" batteries are

shipped without electrolyte and usually have "sell by" dates of one to three

years. Battery dealers will often place their fresher batteries in the rear of

the battery rack or in a storage room. The date of manufacture is often

stamped on the case or printed on a sticker. If possible, have a new battery

tested to insure it meets or exceeds it's advertised specifications, and

recharged if necessary, before it leaves the store.



7.8.6. Look for longer free replacement warranties.



Pro rated battery replacement warranties are not necessarily indicative of

the quality or cost over the life of the battery. The exception is the free

replacement warranty, which represents the risk that the dealer, distributor,

or manufacturer is willing to assume.









7.9. How Do I Size The Components For Backup AC Power?



For AC backup power, here are the basic steps for sizing the deep cycle battery

bank, inverter, AC battery bank charger and generator based on your AC power

requirements. Deep Cycle battery bank capacity sizing is based on power

requirements, inverter efficiency, wiring power loss, discharge rate (or Peukert

73

Effect), electrolyte temperature, and desired average Depth-of-Discharge. DC to

AC Power Inverters has a simple and easy to use battery capacity calculator at

http://www.dcacpowerinverters.com/faq.htm#22.



7.9.1. Calculate the cumulative daily AC load in amps hours (AH) at 120 VAC. This will

require determining how much current an appliance uses and for how long times the

"duty cycle" (the amount of time the appliance is on during that time period). The label

of the electrical appliance will have the amount of power and the voltage that the

appliance uses. Power is expressed either in watts or in amps. If wattage is given,

divide it by the voltage to convert to the number of amps.







For example:



a. Two 60 watt lights that you use continuously for four hours, the calculation would

be 60 watts/120 volts = .5 amps x 4 hours x 2 lights = 4 Amp Hours @ 120 VAC.



b. A 200 watt refrigerator that is on for 24 hours with a 25% duty cycle, the calculation

would be 200 watts/120 volts = 1.67 amps x 24 hours x 25% duty cycle = 10 Amp

Hours @ 120 VAC.



c. A five amp power drill that you use 15 seconds at a time for 25 times, the

calculation would be 5 amps x 15 seconds/60 seconds/60 minutes x 25 times =

.52 Amp Hours @ 120 VAC.



c. A 10 amp sump pump that is on 24 hours and has a 50% duty cycle, the calculation

would be 10 amps x 24 hours x 50% duty cycle = 120 Amp Hours @ 120 VAC.



The total daily usage of these four appliances would be 4 AH + 10 AH + .5

AH + 120 AH = 134.5 Amp Hours @ 120 VAC per day.



7.9.2. Depending on the efficiency of the inverter and the power loss in the wiring, it takes

between 12 and 14 amps of 12 VDC power to produce one amp of 120 VAC

power or 24 to 28 amps to produce one amp of 240 VAC. Using the above example

in the worst case, the usage would be 14 x 134.5 AH = 1883.3 Amp Hours per day @

12 VDC.



7.9.3. Depending on the average load on the battery bank, the total daily usage may

have to be adjusted due to the Peukert Effect. Deep cycle batteries are normally rated

by the fully charged capacity divided by the number of hours of discharge it take to

drop to 10.5 VDC. A very common rate is over a 20 hour period and is is expressed

as "C/20". In the example above, 1883.3 AH are being consumed in a 24 hour period

which has a slightly lower rate that over a twenty hour period, so we could probably

decrease the daily usage by 10% or 1883.3 AH x .9 = 1695 AH per day. If all of this

power were consumed over six hour period, you would probably need to increase the

daily usage by approximately 25%.







74

7.9.4. Depending on the temperature of the battery electrolyte, the usage might also have

to adjusted. The example above assumes 80 degrees F. If your battery bank was

operating at 60 degrees F then you would have to increase the usage by 10% and at

32 degrees F, by 20%. Let's assume the batteries are in a heated area at 70 degrees,

so you would increase the daily usage by 5% or 1695 AH x 105% = 1780 AH per day.



7.9.5. Depending how many discharge/charge cycles you want your battery bank to last,

you will need to increase the usage. Let's assume that you are fully recharging the

battery bank daily and using "low end" inexpensive deep cycle batteries that are fully

discharged or 100% average Depth-of-Discharge (DoD) will last 50 cycles, at 80%

average DoD (or 20% State-of-Charge) will last 200 cycles and at 50% average DoD

will last 500 cycles. In this example, for 100% average DoD, you would require a

battery bank with a capacity of 1780 AH to provide for 1780 AH of daily usage, at 80%

DoD (1780 AH/80% = 2225 AH), and at 50% DoD (1780 AH/50% = 3560 AH).

However, you would have to replace the smaller, less expensive battery bank every

50 cycles.



You can determine the optimum battery bank size by multiplying the

number of cycles time the total amp hour capacity divided into the cost. For

a simple example, let's assume that a 225 Amp Hour (C/20) 12-volt deep

cycle battery costs $85. At 100% DoD, 1750 AH/225 AH per battery = 8

batteries x $85 per battery = $680 total cost and 50 cycles x 1780 AH =

89,000 total AH. So $680/89,000 = .764 cents per amp hour. At 80% DoD,

the calculation would be 2225 AH/225 AH per battery = 10 batteries x $85

per battery = $850 total cost and 200 cycles x 2225 AH = 445,000 total AH.

So $850/445,000 = .191 cents per amp hour. At 50% DoD, the computation

would be 3560 AH/225 AH per battery = 16 batteries x $85 per battery =

$1360 total cost and 500 cycles x 3560 AH = 1,780,000 total AH. So

$1360/1,780,000 = .076 cents per amp hour. In this example, a larger, more

expensive battery bank with a lower average 50% DoD will cost

approximately one tenth the cost of fully discharging the battery bank

(100% DoD) every cycle. This example does not take into consideration the

additional maintenance, cabling cost, cost of money, etc. that would be

used in a Total Cost of Ownership determination.



7.9.6. Once you have determined your daily capacity, then you need to determine how

many hours or days you want to run using your battery bank before you recharge your

batteries and decrease or increase the size of the battery bank accordingly. Please

see Section 9 for more information on charging.



7.9.7. To size the inverter (or inverter portion of an inverter charger using the example

above, calculate the worst case load (with all the appliance on at once) which is (60

watts x 2 lights) +200 watts + (5 amps x 120 volts) + (10 amps x 120 volts) = 2120

watts @ 120 VAC. Be sure to consider the start surge power requirement of up to five

time the run current with large inductive starting loads, such as motors and

transformers. Some "square wave" or "modified" sine wave inverters are not capable

of providing the power to run some motors, compressors or other electronic or

electrical appliances. In these cases, a "true" sine wave inverter must be used. For

more information on power inverters, please see Don Rows' Frequently Asked

Questions about Power Inverters.

75

7.9.8. To size the battery charger (or charger portion of an inverter charger), you will

need the output to be at least 12% of the battery capacity used to fully recharge the

batteries within 24 hours. Using the example above, you would need at least a 214

amp charger to replace 1780 AH in 24 hours.



7.9.9. To size an AC generator, using the example above without recharging the battery

bank, the worst case load (with all the appliance on at the same time) is (60 watts x 2

lights) + 200 watts + (5 amps x 120 volts) + (10 amps x 120 volts) = 2120 watts @

120 VAC. You would also need to consider the surge power requirement up to five

times the run load. If you are using motors, take into consideration their peak starting

current. If the batteries need to recharged the batteries in addition to using the

appliances, add 214 amps/12 DC amps per AC amp = 17.8 amps @ 120 VAC x 120

volts = 2140 watts @ 120 VAC to power the battery charger. So, to power both the

load and recharge the batteries, a generator with a capacity of 8000 to 12000 watts @

120 VAC in required depending on the surge of the pump motor and battery charger.



As can be seen from this example, using just battery backup for one day for AC

power with a heavy load can become very expensive, so that is why most "grid" or

commercial AC power backup systems is an AC generator, combination of

batteries and AC generator, or combination of battery and solar power with AC

generator backup.









76

8. HOW DO I INSTALL NEW BATTERIES?



Last Updated on December 25, 2005





INDEX:



8.1. Installing Car and Marine Batteries



8.2. Installing Deep Cycle Batteries



While working with car or deep cycle lead-acid batteries, please wear glasses to protect

your eyes in the unlike event of an explosion. Do NOT install wet lead-acid batteries in

confined area where there is ANY possibility that salt water can mix with the battery's

electrolyte, like the bilge of a boat, because DEADLY chlorine gas is produced.



8.1. Installing Car and Marine Batteries



In a 2003 marketing study in the U.S., consumers (or non-professional battery installers)

installed almost 60% of the approximately 82 million replacement car batteries that were made

in 1999. Car batteries were the fourth most popular item purchased among auto parts. The

same study indicated that Wal-Mart (EverStart) has surpassed Sears (DieHard) as the number

one car battery seller in the United States with Auto Zone (DuraLast) as the most popular of the

U.S. auto parts stores for car batteries.



Below are some questions you need to ask yourself because the installation of a replacement

battery and disposal of the old one is usually included in the purchase price at some auto parts

and battery stores:



 How much money or time do I save if I install it myself?



 Where is the battery located? Some car manufacturers locate the

OEM (Original Equipment Manufacturer) battery under the rear seat,

trunk or in the fender behind an access door in the wheel well.



 A car battery weights between 30 and 60 pounds (13.6 and 27.3 Kg)

and deep cycle battery can weigh several hundred pounds (or kilos),

so am I physically capable of install it?



 What do I do with the old battery if not exchanged for the new one?

This is especially important if the batteries are not lead-acid, for

example, Ni-Cad. The proper disposal of a non lead-acid battery

could cost more that a new battery.



 How do I save the radio station presets, emissions computer

settings, or security codes before disconnecting the old starting

battery?



 Do I want to risk an injury or holes in my clothes?

77

If you decide to proceed, following is a list of easy steps to replace your battery and assumes

that there the electrical and charging systems are in good condition:



8.1.1. In a well ventilated area, fully charge and test the new battery. Please see Section 9

for charging and Section 4 for testing the battery. If the battery is dry charged (shipped

with out electrolyte), add the electrolyte but do not overfill, let stand for approximately one

hour, and then slowly charge the battery at no more than 1% of the CCA or 10% of the

amp hour capacity.



8.1.2. If a non-sealed wet battery, check the electrolyte levels after the battery has reached

room temperature and "top off" to the proper level with distilled, deionized or

demineralized water as required, but do not over fill. The plates need to be covered

with electrolyte at all times to prevent an internal battery explosion or sulfation.

Please see Section 3.2 for electrolyte fill level diagram.



8.1.3. Thoroughly wash and clean the old battery, battery terminals and tray (case or box)

with warm water to minimize problems from acid or corrosion. Please see Section 3.4 for

more information on corrosion.



8.1.4. Mark all of the battery cables so you will know how to reconnect to proper battery

post or terminal and check the cables and cable terminals closely for damage. A loose

terminal connection, corrosion, bad crimp (in especially a battery cable terminals with

multiple wires into it), or cut cable will cause high resistance and a large voltage drop

when high current is running though it. If the cables are reversed, you can do

extensive damage to your electrical system.



8.1.5. To prevent voltage spikes from damaging electronic equipment such as the emissions

computer and to save the radio station presets, emissions computer and security code

settings, temporarily connect a second 12-volt battery in parallel to the electrical system

before disconnecting the first battery. If active when the key is off, a cigarette lighter plug

can be used to easily connect a 12-volt parallel battery. Cigarette lighter adapters are

available at electronics stores and "Computer Memory Saver" with a 9-volt battery are

available at some auto parts stores, like JC Whitney for about $10.



8.1.6. Turn off all the ignition switch, electrical switches and breakers and electronic and

electrical accessories and appliances. Without using a hammer on the battery cable

terminals or posts, remove the NEGATIVE (-) cable first because this will minimize the

possibility of shorting the battery when you remove the other cables. Secure the negative

cable so that it cannot "spring" loose and make electrical contact. Next remove the

POSITIVE (+) cable. Please remember that the battery terminal connector on the end of

the POSITIVE (+) battery cable maybe "hot" (or have voltage on it from a parallel

battery), so put it in a small plastic bag or cloth around it so that it will not touch the metal

frame or engine components.



8.1.7. Carefully lift the old battery out and dispose of it by exchanging it when you buy your

new replacement battery or by taking it to a recycling center. For additional information

on recycling batteries, go to http://www.batterycouncil.org/recycling.html. Please

remember that batteries contain large amounts of harmful lead, acid and other chemicals,

so take great care with safety and please dispose of your old battery properly to protect

our fragile environment.

78

8.1.8. After removing the old battery, insure that the battery tray or box, cable terminals, and

connectors are clean. Auto parts or battery stores sell an inexpensive brass wire brush

that will clean the inside of post terminal clamps and the post terminals. If the terminals,

cables or hold-down brackets are corroded, replace them. A broken hold down bracket

will cause excessive battery vibration and that will cause a premature battery failure.

Replace any battery cables that are corroding, swelling or other damage with equal or

larger diameter cable. Larger cable is better because there is less voltage drop. Please

see Exide's Voltage Drop in Cables for additional information.



8.1.9. Check the positive and negative terminal markings on the replacement battery and

position it so that the NEGATIVE (-) cable will connect to the NEGATIVE (-) terminal.

Reversing the polarity of the electrical system can severely damage or DESTROY

it. It can even cause the battery to explode.



8.1.10. After replacing and tightening the hold-down bracket, remove any plastic caps or

covers on the terminals of the replacement battery, and reconnect the cables in reverse

order, that is, attach the POSITIVE (+) cable first and the NEGATIVE (-) cable last. For

General Motors-type side terminals, check the length of the bolt and do not tighten more

than 5 to 10 foot pounds, or you could crack the battery case. For top terminals, do not

tighten more than 10 to 15 foot pounds. Connections need to be periodically checked for

corrosion (or oxidation) and retightened, including the grounding cables between the

vehicle's frame and engine block.



8.1.11. To prevent corrosion, coat the terminals and exposed metal parts. Please see

Section 3.4 for more information on corrosion.



8.1.12. Remove the parallel battery and rest all the switches and breakers, if required.



8.1.13. Test the new battery by starting your engine or with an electrical load.



Some vehicles are have battery electrolyte level sensors. For Toyota and Nissan, use the

sensor bypass information at

http://www.exide.com/products/trans/na/battery_care/toyota_nissan.pdf and for Mazda use

http://www.exide.com/products/trans/na/battery_care/toyota_nissan.pdf.









8.2. Installing Deep Cycle Batteries



Most of the steps above for installing car batteries apply to installing deep cycle batteries with

these notable exceptions. Wire sizing and cable lengths are very important because wiring that

is not large enough or different lengths will cause excessive voltage loss and under charged

batteries or, in some cases, a fire. Wiring size (and fusing) should be based on the maximum

possible current carried through the wire. A good source of information for measuring maximum

cable and connector voltage drops can be found at Exide's Caring For Your Battery. Batteries

connected in parallel should have the same cable lengths and size from the charging or

discharging source. Use of buss bars are highly recommended for larger deep cycle battery

bank installations. A good source of information of wire sizing can be found at



79

http://www.powerstream.com/Wire_Size.htm or http://www.solarexpert.com/Photowiring.html.

Using properly sized fuses or circuit breakers is also very important because they can provide

protection for the wiring from over heating and for the electrical appliances. A good source of

basic information on connectors, fuses and wire can be found on howstuffworks or Perry

Babin's Basic Car Audio Electronics Web site at http://www.bcae1.com/fuses.htm and

http://www.bcae1.com/wire.htm. Using rotary A/B battery selector switches are not

recommended because the heavy inrush of current during the first few milliseconds that a switch

is closed can burn the contacts or arc. Series, parallel, and series-parallel battery connection

wiring diagrams can be found in Section 7.3.2. Connections will need to be periodically

retightened. A good source of information on measuring for maximum voltage drops can be

found at Exide's Caring For Your Battery.



Insure there is adequate ventilation for the batteries so the gas can dissipate while recharging

and the batteries can stay cooler. In other words, do NOT use sealed battery boxes, even with

sealed Gel Cell or AGM VRLA batteries. Some batteries will require up to 30 "preconditioning"

cycles before they will produce their rated capacity. This is because the acid needs to fully

penetrate the pores of the newly formed plates. When mixing sulfuric acid and water to make

electrolyte for dry charged batteries, always add the acid to the water.









80

9. HOW DO I CHARGE (OR EQUALIZE) MY BATTERY?



Last Updated on February 26, 2005





INDEX:



9.1. What Are the Four Stages of Battery Charging?



Charging Algorithms



9.2. Additional Words of Caution



9.3. Battery Charger Types



9.3.1. Vehicle Charging System



9.3.2. Manual Constant Current Charger



Current Charging Table



9.3.3. Manual Constant Voltage Charging



Constant Voltage Charging Table



Constant Voltage Charging Temperature Compensation Table



9.3.4. Manual Tamper Current Charger



9.3.5. Automatic Constant Voltage or Taper Charger



9.3.6. "Smart" Microprocessor-Controlled Charger



9.3.7. Float Charger and Battery Maintainer



9.3.8. Trickle Charger



9.3.9. High Rate Fast, Boost or Starting Assist Charger



9.3.10. DC Generators



9.3.11. Inverter/Charger



9.4. How Long Does It Take to Recharge a Good Battery?



9.5. How Do I Know When My Battery Is Fully Charged?



9.6. How Do I Know If My Battery Is Overcharged?

81

9.7. Battery Charger Buying Tips



9.8. Is Opportunity Charging Worthwhile?



9.9. Is Gassing Good For a Wet Battery?



9.10. What is the Difference Between a Converter and a Charger?



9.11. What Are Charge Controllers or Voltage Regulators?



9.12. How Long Will a Deep Cycle Battery Last On a Single Charge?



9.13. How Can I Reduce Recharging Time?



9.14. How Can I Adjust the Specific Gravity?



9.15. How Do I Recharge Small SLA Batteries?



9.16. How Do I Recharge Unevenly Discharged or Non-Identical Batteries at the

Same Time?



9.1. What Are the Four Stages of Battery Charging?



Three stages--bulk, absorption and float are normally used for wet car and motive

deep cycle batteries with an optional equalizing stage. Three stages--bulk,

absorption and float are normally used for VRLA (gel cell and AGM) car and

motive deep cycle batteries. Three stages--bulk, float and equalization are

normally used for wet stationary deep cycle batteries and two stage--bulk and float

are normally used for VRLA stationary deep cycle batteries with an optional

equalization stage is some cases.



9.1.1. The BULK stage is where the charger current is constant and the battery voltage

increases, which is normally during the first 80% of the recharge. Give the battery

whatever current it will accept as long as it does not exceed 25% of the 20 hour

(expressed "C/20") ampere hour (AH), 10% of the RC rating, and wet batteries do

exceed 125° F (51.5° C) and VRLA batteries do not exceed 100° F (37.8° C).



9.1.2. The ABSORPTION stage is where the charger voltage, depending on the battery

type, is constant between 14.1 VDC and 14.8 VDC at 80° F (26.7° C) and the current

decreases until the battery is fully charged, which is typically the last 20% of the

recharge. For wet batteries, gassing (making a bubbling sound) usually starts at 80%

to 90% of a full charge. A full charge normally occurs when the charging current drops

off to 2% (C/50) or less of the AH capacity of the battery and each cell of a wet battery

is moderately gassing equally. For example, end current for a 50 AH (C/20) battery is

approximately 1.0 amp (1000 milliamps) or less. If the battery will not "hold" a charge,

the current does not drop after the estimated recharge time, and a wet battery is hot

(above 125° F (51.5° C)), then the battery may have some permanent sulfation.

Please refer to Section 16 for more information about sulfation and how to remove it.





82

Two stage chargers normally have the bulk and absorption stages and must be turn

off when the battery is fully charged to prevent overcharging.



9.1.3. The optional FLOAT stage is where the charge voltage, depending on the battery

type, is reduced to between 13.0 VDC and 13.8 VDC at 80° F (26.7° C), held

constant. It can be used indefinitely to maintain a fully charged battery to overcome

the natural self-discharge of the battery. The current is reduced to approximately 1%

(C/100) or less. Three stage chargers usually have the bulk, absorption and float

stages. Please refer to Section 13 for more information about storing batteries and

float charging. Three stage chargers usually have the bulk, absorption and float

stages.



9.1.4. The optional EQUALIZING stage is a controlled 5% to 10% absorption overcharge

to equalize and balance the voltage and specific gravity in each cell. Equalizing

reverses the build-up of the chemical effects like electrolyte stratification where acid

concentration is greater in the bottom of the battery. It also helps remove sulfate

crystals that might have built up on the surface or in the pours of the plates. The

recommended frequency varies by motive deep cycle battery manufacturers from

once a month to once a year. For stationary deep cycle batteries, some short daily (30

minutes or less) equalizations have proven to be beneficial and not require the longer

equalization cycles. They are not as hard on a wet battery because they do not

produce as much gas or heat the battery. You should equalize wet batteries when one

or more of the following occur:



 Where the temperature compensated Specific Gravity reading

difference between cells is .030 (or 30 "points") or greater



 Where the temperature compensated Specific Gravity reading

difference of a cell is .010 (or 10 "points") or more below the reading

for a fully charged cell when the battery is fully charged



 When one cell requires more water than all the other cells



 When one cell does not require as much water as all of the other

cells



 When the SoC measured by a hydrometer does not materially agree

with the SoC measured by an accurate (.5% or better) digital

voltmeter



Some AGM VRLA batteries, like Concorde, can be equalized under certain

conditions, but carefully follow the battery manufacturer's recommended

procedures or you will damage the battery.



To equalize, check that the electrolyte is covering the plates in each cell

and fully recharge the battery. Then increase the charging voltage to the

battery manufacturer's recommendation, or if not available, add 5% to 10%

to the absorption charging voltage. Heavy gassing should start occurring

in each cell. Do not allow the wet battery to get above 125° F (51.5° C)

or a VRLA battery above 100° F (37.8° C). Take Specific Gravity readings

83

in each cell once per hour. Stop equalizing when the Specific Gravity values

no longer rise during the gassing phase and when every cell is gassing

evenly. Insure that the plates are covered with electrolyte at all times, and

add distilled, deionized or demineralized water if required, but do not

overfill. Only equalize if the battery manufacturer recommends it. Four

stage chargers typically have the bulk, absorption, float and equalization

stages.



An excellent and easy to understand tutorial on battery charging basics can be found at

http://batterytender.com/battery_basics.php. The following graphs are examples of

charging algorithms used by Deltran [Battery Tender] for power sport, car and deep cycle

batteries:



Wet Standard (Sb/Sb)









Wet Low Maintenance (Sb/Ca)









84

Wet "Maintenance Free" (Ca/Ca)









85

Absorbed Glass Mat (AGM) VRLA









Gel Cell VRLA









86

[Source: Deltran]



It is extremely important to use the battery manufacturer's recommended

temperature compensated charging voltages and procedures whenever possible

for optimum battery capacity, maintenance and service life. A good rule-of-thumb is

not to use a charger (or charging setting) for batteries that is greater than 25% of the AH

(C/20) capacity or 10% of the RC rating of the battery or batteries being charged. For

example, if the battery has RC of 100 minutes, do not use charger that will exceed 10

amps. The exception is when you are charging a large AGM deep cycle battery bank.

Due of the acceptance rate of the AGM batteries a larger alternator to 33% of the

capacity of the battery bank being charged can be used. Using a smaller alternator,

unless temperature protected, might be damaged.









9.2. Additional Words of Caution and Charging Tips:



9.2.1. Help prevent blindness and always wear glasses when working around a car

or deep cycle battery in the unlikely event that it might explode.



9.2.2. Use the battery manufacturer's charging recommendations and temperature

compensated voltages whenever possible for optimum capacity, maintenance and

service life. MATCH the charger (or charger's setting) for the battery type you are

recharging (or maintaining) and insure the charging voltages are compatible. Except



87

for VRLA Gel Cells, a small overcharge is slightly better than an undercharge.

Overcharging Gel Cell batteries can cause voids between the plates and loss of

capacity will result.



9.2.3. Lead-acid batteries should always be recharged within 24 hours after they have

been used and the sooner the better. Before recharging, check the electrolyte and

insure that it is not frozen and that it covers the plates at all times to prevent sulfation

and to reduce the possibility of an internal explosion. Do not recharge frozen batteries

because you will damage them. Allow them to thaw out first.



9.2.4. After recharging, recheck the electrolyte levels after the battery has cooled, top off

with distilled, deionized or demineralized water as required, but do not overfill.

(Please refer to Section 3.1. for more information about filling batteries.)



9.2.5. Reinstall the vent caps on wet (flooded) batteries before recharging and recharge

ONLY in well-ventilated areas because explosive are and toxic stibine or arsine

gasses can be produced during the absorption stage. Insure the vent caps are not

clogged. Do NOT expose lead-acid batteries to a lit cigarette, sparks or flames

because they produce flammable gasses and could explode.



9.2.6. Follow the charger manufacturers' procedures for connecting and disconnecting

cables. Connect the positive (+) lead of the charger to the positive (+) terminal post of

the battery to be charged and the negative (-) lead of the charger to the negative (-)

terminal post. Operate in a manner to minimize the possibility of an explosion or

incorrectly charge the battery. You should always turn the charger OFF or unplug it

before connecting or disconnecting cables to a battery. Do not wiggle the cable

clamps while the battery is recharging, because a spark might cause an explosion.

Good ventilation or a fan is recommended to disperse the gas created by the

recharging process for wet batteries. As a safety feature, some chargers are designed

not operate unless the battery has a partial charge or if the leads are reversed.



9.2.7. If a wet battery becomes hot, over 125° F (51.5° C), or if it violently gasses or

spews electrolyte, turn the charger off temporarily or reduce the charging rate. This

will also prevent "thermal runaway" that can occur with VRLA (AGM or Gel Cell)

batteries if the battery temperature is over 100°F (37.8° C). If an air cooled alternator

becomes too hot during the bulk charging phase, stop and let it cool down or use an

alternator temperature sensing voltage regulator, like a Balmer or a water cooled

alternator, Bosch for example.



9.2.8. Insure that charging the battery with an external charger will not damage the

electrical system or appliances with high voltages. If this is even a remote possibility,

then disconnect the grounded battery cable from the battery before connecting the

charger.



9.2.9. If you are recharging Gel Cell VRLA batteries, the battery manufacturer's charging

voltages are very critical. You might need special charging equipment. In most

cases, standard deep cycle chargers used to recharge wet batteries cannot be used

to properly recharge Gel Cell or AGM VRLA batteries because of their higher voltages

or charging profiles. Overcharging Gel Cell and AGM batteries will significantly



88

shorten battery service life or cause "thermal runaway" if the battery temperature is

over 100°F (37.8° C).



9.2.10. If a battery is charged with a manual or defective charger and all the

electrolyte is "boiled" out, some batteries can cause a FIRE or produce

DEADLY CO (Carbon Monoxide) or other gasses.



9.2.11. Routinely tighten cables connections.



9.2.12. Never disconnect a car battery cable from a vehicle with the engine running,

because the battery acts like a filter for the electrical system. Unfiltered (pulsating DC)

electricity sometimes exceeding 40 volts and can damage expensive electronic and

electrical components such as emissions computer, audio system, charging system,

alarm system, etc.



9.2.13. Alternators are not designed to recharge dead (or flat) batteries and the stator can

be burned or diodes go bad if used in that manner.



9.2.14. Wet battery gassing usually starts at 80% of a full charge. A full charge normally

occurs when the charging current drops off below 2% (C/50) of the AH capacity and

the battery is moderately gassing (bubbling). For example, the end current for a good

50 AH (C/20) battery is approximately 1.0 amp (1000 milliamps) or less depending on

the type.



9.2.15. Do not recharge batteries with cracked or leaking battery cases.



9.2.16. Recharge battery banks the same way you discharged them. For example, if you

discharged two or more fully charged and identical batteries connected together such

that all the batteries discharged the same, i.e., the same State-of-Charge (SoC)

readings on all of the batteries, you should recharge them connected the same. If you

discharged two or more fully charged and identical batteries not connected together

such that the batteries discharged differently, i.e., different State-of-Charge readings

on each of the batteries or banks, you should recharge them separately. When the

batteries are connected together in a bank(s), it is a question for keeping the

discharges and charges balanced; otherwise, you will undercharge or overcharge

one or more of the batteries or banks. Overtime, undercharging will reduce capacity

due to the accumulation of sulfation. The total time to recharge the batteries or banks

together or individually is about the same because you have to replace the amp hours

consumed.



9.2.17. Do not recharge batteries directly from a gas or diesel powered generator that

does not have regulated DC voltage and most do not. A better approach to recharging

batteries is to power a "smart" battery charger with the generator so the batteries are

not overcharged or undercharged.









9.3. Battery Charger Types

89

There are basically three battery charger configurations--single bank, multi-bank

and multi-station. A single bank charger is one that is designed to provide a single

voltage to recharge a single battery or bank of batteries. It is by far the most widely

used configuration. A multi-bank charger provides single voltages to multiple

banks of batteries by using an internal isolator. This type of charge can also act as

a single bank charger and commonly used to recharge unbalanced two, three or

four 12-volt batteries in series to power a motor. A multi-station charger is a used

to recharge more than one battery at the same time. It is functionally two or more

single bank chargers in the same case.



Unless the charging system or charger has adjustable voltage settings, there is no

one system that can recharge all battery types. For example, if the absorption

charge voltage is set for a Low Maintenance (Sb/Ca) or AGM VRLA battery at 14.4

VDC, the system would undercharge most wet Standard (Sb/Sb) or wet

"Maintenance Free" (Ca/Ca) and overcharge some Gel Cell starting batteries. This

would reduce the battery's service life. Some chargers are equipped with an

electronic switch that senses battery voltage at some predetermined level before

the charger will operate. For deeply discharged batteries, this gives the

appearance that they can not be recharged. Please see the charger

manufacturer's operator manual for instructions on how to override this "soft start"

feature. A good quality charger used on a cheap battery is better than a bad

quality charger used on a good battery.



9.3.1. Vehicle Charging System



A vehicle charging system is made up of three components, an alternator

(or DC generator), voltage regulator and a battery. Usually when a vehicle

is jump started, it is NOT driven long enough to fully recharge the battery.

The length of time to fully recharge the battery depends on the amount of

discharge, the amount of surplus current that is diverted to the battery, how

long the engine is run, engine speed, and ambient temperature. An

alternator is sized by the vehicle manufacturer to carry the maximum

accessory load and to maintain a battery and NOT to recharge a dead

battery. For example, if 300 amps were consumed for two seconds to start

a car from a fully charged battery, it will take an 80 amp charging system

approximately eight seconds to replace the .167 amp hours of power used.

If 25 amps are available to recharge the battery, it will take 24 seconds and

10 minutes at one amp. With a dead 120 minute RC (60 amp hour) battery,

it would take approximately 45 minutes at 80 amps, 2.4 hours at 25 amps,

or 60 hours at one amp to obtain a 80% State-of-Charge (SoC) and double

the time to fully charge it.



More information can be found in Section 5 or Dan Landiss' Car Batteries

Are Not 12 Volts on http://www.landiss.com/battery.htm about vehicle

charging systems. Some battery experts believe that some vehicle charging

systems undercharge starting batteries and that the batteries should be

periodically recharged with an AC powered battery charger to optimize their

service life by removing accumulated lead-sulfate or electrolyte

stratification.



90

If you have added after-market lights, winches, audio amplifiers, two-way

radios or other high powered accessories to your vehicle and engage in

stop-and-go driving, the vehicle's charging system might not produce

enough current or voltage to keep your battery fully charged. You might

need to increase the capacity of the charging system. If you are also

recharging deep cycle battery banks, please see the caution in

Section 9.2.7. above. Ideally the combined load of all the accessories

should be less than 75% of the charging system's maximum output, so that

at least 25% is available to recharge the battery.









VEHICLE CHARGING VOLTAGE









[Source: Bosch]









9.3.2. Manual Constant Current Charger



A manual constant current charger chargers the battery at a constant

current rate and the battery voltage will increase as the State-of-Charge

rises. If you use an external constant current charger, set it to deliver NO

more than the lessor of 1% of the CCA, 12% of the RC rating, or 25% of the

C/20 rated AH Capacity of the wet battery and also carefully monitor the

current flowing into the battery. C-rate is a measurement of the charge or

91

discharge of battery overtime. It is expressed as the Capacity of the battery

divided by the number of hours to recharge or discharge the battery. For

example, a 48 amp hour battery would have a charging or discharging rate

of 4.8 amps for ten hours. With manual chargers, you need to determine

how many amp hours have to be replaced and determine the amount of

charging time based on the constant current output of your charger. Manual

constant current chargers will overcharge a battery if not turned off

when the battery is fully charged. Some constant current chargers have

a timer that can turn off the charger will help prevent it from overcharging

the battery. These types of chargers are not recommend to recharge a

VRLA battery because the absorption voltages are critical, especially for gel

cell batteries.



For fully discharged wet batteries, the following table lists the

recommended battery charging rates and times using a constant current

charger:







CONSTANT CURRENT CHARGING

Reserve Capacity Slow Charge Fast Charge

(RC) Rating (RECOMMENDED)

80 Minutes or less 15 Hours @ 3 5 Hours @ 10

[32 ampere hours or amps amps

less]

80 to 125 Minutes [32 21 Hours @ 4 7.5 Hours @ 10

to 50 ampere hours] amps amps

125 to 170 Minutes 22 Hours @ 5 10 Hours @ 10

[50 to 68 ampere amps amps

hours]

170 to 250 Minutes 23 Hours @ 6 7.5 Hours @ 20

[68 to 100 ampere amps amps

hours]

Above 250 Minutes 24 Hours @ 10 6 Hours @ 40

[over 100 ampere amps amps

hours]





[Source: BCI]









92

9.3.3. Manual Constant Voltage Charger



A manual two stage (bulk and absorption) constant voltage charger applies

a regulated voltage to the battery at a constant level during the absorption

stage. The current drops to below 2% (C/50) of the battery's capacity when

it approaches 100% State-of-Charge. The recommended charging method

using a constant voltage charger is to slowly recharge the battery using a

charger sized to recharge the battery over a ten-hour period (C/10). To

prevent damage to a fully discharged battery, the current should be less

than 1% of the CCA (Cold Cranking Amps) rating during the first 30 minutes

of charge. The charger (or DC power supply) should be adjusted to the

battery manufacturer's absorption, float or equalizing voltage

recommendations. Typical battery charging voltage ranges are in the table

below with the electrolyte temperature compensated to 80° F (26.7° C).

Manual constant voltage charger (or DC power supply) will overcharge

and damage a battery if not turned off when the battery is fully

charged.







COMMON BATTERY CHARGING VOLTAGE RANGES

@ 80 Degrees F (26.7 Degrees C)



Battery Type Charging Float Equalizing

Ca=Calcium Voltage Voltage Voltage

Sb=Antimony

Wet Standard 14.5- 13.0- 15.4-16.0

(Sb/Sb) Deep 14.8 13.2

Cycle

Wet Low 14.4- 13.1- 15.1-16.4

Maintenance 14.6 13.2

(Sb/Ca)

Wet 14.8 13.1- 15.5-16.3

"Maintenance 13.4

Free" (Ca/Ca)

AGM VRLA 13.8- 13.2- Not

15.0 13.8 Applicable

in most

cases

Gel Cell VRLA 14.1- 13.2- Not

14.4 13.8 Applicable

93

Most vehicle charging systems are temperature compensating; however, if

the external charger is NOT temperature compensating, you should adjust

the charging voltage from the table below to correct for the temperature of

the battery. For example, if the electrolyte temperature is 20° F (-6.7° C),

then increase the charging voltage to 15.788 volts for a Wet Low

Maintenance (Sb/Ca) battery if the normal charging voltage is 14.6 at 80 °

F. If 100° F (43.3° C), then decrease the charging voltage to 14.204 volts

for the same battery.







CHARGING VOLTAGE

TEMPERATURE COMPENSATION

@ 3.3mv/degree F/cell



Electrolyte Electrolyte Add to

Temperature Temperature Charger's

Degrees F Degrees C Output Voltage

160° 71.1° -1.584

150° 65.6° -1.386

140° 60.0° -1.188

130° 54.4° -.990

120° 48.9° -.792

110° 43.3° -.594

100° 37.8° -.396

90° 32.2° -.20

80° 26.7° 0

70° 21.1° +.198

60° 15.6° +.396

50° 10° +.594

40° 4.4° +.792

30° -1.1° +.990

20° -6.7° +1.188

10° -12.2° +1.386

0° -17.8° +1.584







94

9.3.4. Manual Taper Current Charger



The taper current chargers and have no controlled current and voltage and

are dependent upon the internal resistance of the battery. The current starts

high and tampers off as the voltage increases when the battery approaches

100% State-of-Charge (SoC). With a taper charger, a high current (up to

C/2), can be only applied to non-sealed wet batteries for 30 minutes

maximum or until the battery heats up to 125° F (51.7° C). The current is

then regulated downward by the battery until the charge state reaches

100% where it is at a minimum. A better approach to recharge the battery

with a tamper charger is to size the charger to recharge the battery over a

minimum of a ten-hour period (C/10). This technique allows the acid more

time to penetrate the plates and there is less mechanical stress on the

plates. Manual taper current chargers will overcharge a battery if not

turned off when the battery is fully charged and is not recommend to

recharge VRLA batteries.









9.3.5. Automatic Constant Voltage or Taper (Ferroresonant) Charger



The next step up is an "automatic" two stage (bulk and absorption) charger

that will stop charging when the battery has a full charge by turning itself off

at some predetermined current or voltage cut-off point. If the battery

manufacturer's recommended absorption voltage are used, there is

less chance of overcharging a battery than with a manual charger. A

10-amp automatic starting battery charger will cost approximately $50 (US)

and is suitable for most simple non-gel cell VRLA car battery recharging

charging applications with battery capacities up to 100 amp hours (C/20) or

250 minutes of RC. If left connected, when the voltage drops to

predetermined point (normally 90%-95% SoC) due to self-discharge, some

better automatic chargers will turn itself back on and recharge the battery.

Better quality automatic chargers will also include temperature

compensation, which is critical if recharging occurs in temperatures other

than 80° F (26.7° C), do not produce sparks if the polarity of the clamps are

reversed, and will help prevent VRLA battery "thermal runaway".









9.3.6. "Smart" Microprocessor-Controlled Charger



The best chargers for wet and some AGM starting and motive deep cycle

batteries are four-stage "smart" microprocessor-controlled temperature

compensating chargers. They will automatically switch between bulk,

95

absorption, float, and equalizing charging and some have adjustable

voltage set points or switches for the different wet battery types and

automatic temperature compensation. The best chargers for Gel Cell or

AGM VRLA batteries are a less expensive three-stage temperature

compensating versions that have bulk, absorption and float charging

capability (or settings) especially designed for these types of batteries. They

will also help prevent VRLA battery "thermal runaway". When continuously

connected, the microprocessor based "smart" chargers can continuously

charge a battery and keep it fully charged indefinitely. Some one to three-

amp three-stage versions cost less than $60 (US). They are ideal for for

Low Maintenance (Sb/Ca) and some Standard (Sb/Sb) and AGM VRLA

deep cycle batteries to 75 AH (C/20) or 188 minutes of RC that are used

once per week or less. Good examples are for power sport vehicles (ATVs,

Jet skis, motorcycles, snowmobiles, etc.), RVs, caravans, farm and lawn

tractors, and antique vehicles.









9.3.7. Float Charger and Battery Maintainer



There are basically two types of float chargers. The first type is used to float

or maintain wet or VRLA car or motive deep cycle batteries and the second

is one to float or maintain wet or VRLA stationary deep cycle batteries.



If you are using wet or VRLA car or motive deep cycle batteries and already

have a tamper or two stage constant current or voltage charger, then a

voltage-regulated "float" charger or battery maintainer set at approximately

13.2 VDC, for example, Vector VEC080, costing less than $30 (US) can be

continuously used after the battery has been fully charged. This will

maintain it at a 100% State-of-Charge with a C/100 rate to offset the

battery's internal self-discharge and prevent it from sulfating. Batteries that

have the same plate chemistry (battery type) can be connected in parallel to

a float charger after they have been fully charged and the charger's current

output is greater than 1% of total amp hour capacity of the batteries

connected to it. If you are using wet or VRLA stationary deep cycle

batteries, then use a float charger at approximately 13.8 VDC that is sized

to carry the maximum load plus an extra 10% depending on how fast you

want to recharge the batteries.









9.3.8. Trickle Charger



Trickle charger is typically a cheap, unregulated voltage (C/100) charger

used to maintain a battery after it has been fully charged typically costing

less than $20. Do NOT use these types of chargers because they can

easily overcharge and destroy the wet battery by "boiling" the electrolyte out

96

and dry out the battery. If you have to use a trickle charger, using a timer is

highly recommended.









9.3.9. High Rate Fast, Boost or Starting Assist Charger



High rate fast, boost or starting assist chargers (or settings) are high rate

chargers that are designed to provide high current to for up to 15 seconds

to start your engine when the battery is discharged. These types of

chargers (or settings) to recharge your battery are NOT RECOMMENDED

because they can easily overcharge and destroy it with the excessive

current or voltage. If one is used, please do it with extreme caution and

adhere to the charger manufacturer's recommended procedures.



9.3.10. DC Generators



Generators capable of producing Direct Current were used up until the

1950's to recharge car batteries. They were replaced by alternators

because generators were not as reliable because of their mechanical

voltage regulation, expense to manufacturer, and added weight. Most

portable "generators" used today are alternators to produce AC voltage.

Some have rectifiers (or diodes) to produce "DC" voltage to recharge

batteries. These portable generators can provide a bulk (up to 80% State-

of-Charge) or equalizing charge to a battery that has been disconnected

from the it's load. But recharge with care and monitor the process because

they typically do not have voltage regulation, can easily overcharge the

battery and destroy it. Chargers without voltage regulators are NOT

RECOMMENDED for absorption or float charging.



9.3.11. Inverter/Charger



Inverter/Charger is an DC to AC converter popularly known as an inverter

with a builtin charger. Some manufacturers of inverter/chargers are

Mastervolt, Newmar, Parallax, Progressive Dynamics, TrippLite, Victron,

Xantrex, and others. When selecting an inverter/charger be sure that the

charger matches the battery type you are trying to charge and will produce

the battery manufacturer's recommended temperature compensated

charging voltages. Some inverter-charger combinations are float chargers

for stationary batteries and will only produce approximately 13.8 VDC, so

your need to periodically give the batteries an absorption or equalizing

charge to extend their overall service lives.



Hyperlinks to battery chargers, "smart" chargers, float chargers and battery

maintainers can be found in the Battery References and Information Links List at

http://www.batteryfaq.org. Please remember to match the charger to the battery

manufacturer's recommended temperature compensated charging voltages for





97

that type of battery or match the batteries to the charger capability. The better the

match, the longer the service life and more capacity the battery will have.









9.4. How Long Does It Take To Recharge a Good Battery?



When a battery is discharged, more power has to be replaced due to loss.

However, some of the power is converted to heat and lost due to the resistance in

the cables, connectors and elements within the battery. For most starting batteries

that are discharged less than 10% of their full capacity, an estimate of time is the

amp hours to be replaced divided by the current output of the charger. For

example, a 40 amp hour battery with a 5% discharge would require approximately

two amp hours to be replaced. Using five amp charger, it would take

approximately 24 minutes (2/5x60) to recharge the battery. A 10 amp charger

would take approximately half the time or 12 minutes. For batteries that are

discharged more than 20% of their full capacity, an estimate of time is twice the

amp hours to be replaced divided by the current output of the charger. For

example, a 40 amp hour battery with a 95% discharge would require

approximately 38 amp hours to be replaced. Using five amp charger, it would take

approximately 15.2 hours recharge the battery. A 10 amp charger would take

approximately half the time.









9.5. How Do I Know When My Battery Is Fully Charged?



In descending order of accuracy and depending on the battery type, one of the

following three methods is normally used to determine if a battery is fully charged.

After the battery has cooled to room temperature, recheck the electrolyte levels.

The plates must be covered at all times to prevent an internal explosion or

sulfation.



9.5.1. According to IEEE 450-2002 Annex B Recommended Practice, "The pattern of

charging current delivered by a conventional voltage-regulated charger after a

discharge is the most accurate method for determining state of charge. As the cells

approach full charge, the battery voltage rises to approach the charger output voltage,

and the charging current decreases. When the charging current has stabilized at the

charging voltage, the battery is charged, even though specific gravities have not

stabilized." It should be less than two percent of the capacity (C/50) of the battery. For

the average sized car battery (BCI Group 24), that would be less than two amps. With

non-sealed wet batteries, the cells gassing (bubbling) freely and evenly.



9.5.2. Remove the surface charge by one of the methods in Section 4.3., measure the

cells with a hydrometer, temperature compensate, and compare the average of the

readings with the battery's manufacturer's Specific Gravity definition of a cell in a fully

charged battery.

98

9.5.3. Remove the surface charge, measure the Open Circuit Voltage (OCV) with an

accurate (.5% or better) digital voltmeter across the terminals, temperature

compensate, and compare the reading with the battery's manufacturer's OCV

definition of a fully charged battery.



If the battery will not "hold" a charge, the charging current does not drop below 2%

(C/50), and the battery just gets warm or hot, then it might have some permanent

sulfation. Please refer to Section 16 for more information about sulfation and how

to remove it.









9.6. How Do I Know If My Battery Is Overcharged?



Normally, overcharging will consume more water for from a wet battery than

normal and the electrolyte levels will be low. Other signs of overcharging are a

"rotten egg" oder, violent gassing, spewing of electrolyte, black "tide-marks" on the

inside walls of the cells, or black deposits on the bottoms of the filler caps. Other

signs of overcharging are lumpy brown sediment or muddy red or brown

electrolyte.









9.7. Battery Charger Buying Tips



The following are some tips for consumers on buying battery chargers car and

deep cycle lead-acid batteries. Please see Section 7.1 for definitions of the battery

types. An excellent and easy to understand tutorial on Battery Charging Basics

can be found at http://www.batterytender.com/.



9.7.1. Always wear glasses when working around a battery in the unlikely event

that it might explode.



9.7.2. MATCH the charger's output voltages to the battery type and manufacturer's

recommended absorption, float and equalization (if required) charging voltage

requirements. A mismatch can easily overcharge or undercharge the battery. Some

charger manufacturers state that their charger to able to recharge all or most battery

types. There are differences in the charging voltages and profiles for each battery

type, so one charger setting can NOT possibly fit all types of batteries because of the

differences in plate chemistries and alloys used. If the documentation that came with

the battery or charger or the manufacturer's Web site does not state voltages, contact

one of their Customer Service representatives and ask. If you do not charge your

batteries at 80 degrees F (26.7 degrees C), temperature compensation needs to

occur on the charging voltages to properly recharge the battery. A recent study has

shown that cell equalization will significantly increase the life of wet (or flooded)

Standard (Sb/Sb), Low Maintenance (Sb/Ca), "Maintenance Free" (Ca/Ca) batteries,

but is NOT recommended for most AGM or Gel Cell VRLA batteries.

99

9.7.3. Size the charger based on the discharge amount and how fast you need to use the

batteries again. Slow recharging is recommended, so chargers that are sized 10% of

the capacity of wet, AGM or Gel Cell VRLA batteries should be used. Fast or "boost"

charging batteries can kill batteries because they can warp the battery's plates. Do

not exceed the battery manufacturer's charging current or voltage limitations. For

most car batteries, a charger output of four to 10 amps should be sufficient and for

motorcycle and power sports batteries, one to amps. For more information on charger

sizing, please see Chris Gibson's article on

http://www.smartgauge.co.uk/chargesize.html.



9.7.4. Determine special features you want, for example, "automatic shut off" (two

stage), "smart" microprocessor controlled, automatic temperature compensation, "soft

start", portability, waterproofing, indicators, ammeter, lead reversal protection, short

circuit protection, high temperature protection, etc.



9.7.5. Determine the total cost of ownership. Shopping on the Internet by using search

engines, like http://www.google.com or http://www.yahoo.com to find the best prices.

A charger as a long term investment and a good charger used on a cheap battery is

much better than a bad charger used on a good battery.



9.7.6. If you have two stage charger, use a float charger (or battery maintainer). After the

battery has been fully charged with a two stage charger or the vehicle's charging

system, you can continuously maintain the full charge with a voltage regulated, one-

half to two amp float charger matched to your battery type while the battery is not

being used. This will prevent sulfation from occurring while the battery is not being

used. Cheap, unregulated "trickle" chargers can overcharge and destroy your battery.



9.7.7. If you use a small "smart" charger to recharge a large battery, you might have to

periodically "reset" the charger, for example, every eight hours, by unplugging it and

plugging it back in. Some small output "smart" chargers have fixed timers that will

switch the absorption mode to float mode; thus, not allowing sufficient time for a large

capacity battery to be completely recharged. This fixed timer is used to keep a

sulfated battery from boiling dry.









9.8. Is Opportunity Charging Worthwhile?



Opportunity charging is recharging in between the normal daily charging cycle. An

example is a electric fork lift truck battery being recharged when not in use during

the workday and during meal breaks. Some experts will argue that a deep cycle

battery should be sized so that the average Depth-of-Discharge (DoD) should not

fall below 50% (or 80% depending of the plate chemistry) and the battery should

be charged only once per day because each charge cycle removes a microscopic

layer from the entire grid and eventually the upper portion of the grid can not carry

the current. That is one of the main reasons that grid design and composition is

extremely important in car batteries for a long service life. Other experts will argue

that opportunity charging significants lowers the average DoD and causes

100

multiple, shallow cycles per day, which is better that a higher average DoD and

one deep cycle with a lower average DoD. The answer to this question probably

lies somewhere in the middle. You will need to compare the effects of lower

average DoD and multiple cycles vs. greater DoD and one cycle using the battery

manufacturer's data to determine the break even point. Generally, opportunity

charging is good, especially when the average DoD is between 20% and 50% and

you can fully recharge battery at least once during a 24 hour period when being

used and once per week while it is not in use to prevent sulfation.









9.9. Is Gassing Good For a Wet Battery?



When a wet (flooded) 12-volt lead-acid battery reaches the absorption stage which

is approximately 14.4 VDC at 80° F (26.7° C) or 80% State-of-Charge during a

charge, it will start to gas (bubble) and is a normal part of the charging process.

Gassing is the electrolysis of water into two parts Hydrogen gas and one part

Oxygen gas and can be explosive. The gas bubbles given off by the plates will

help to mix the electrolyte as they rise to the surface. This will help to prevent

electrolyte stratification. Electrolyte stratification is acid concentration that is

greater at the bottom of a battery than at the top, especially within larger batteries.

Normal charging should produce moderate amount of even gassing of all cells,

which is good. Overcharging a battery or rapidly charging with high voltage will

produce heavy gassing, heat, consume excessive quantities of water, accelerate

positive grid corrosion, warp the plates, and is NOT recommended. Ventilation is

required for all lead-acid batteries and good ventilation is mandatory for wet

batteries to dissipate the explosive and toxic gasses produced during

charging.









9.10. What is the Difference Between a Converter and a Charger?



An AC-DC Converter (or AC-DC Power Supply) is used to convert 120 or 240 VAC

power to filtered 12 to 13.8 volt DC power to run DC appliances while connected to

"shore power" instead of running on battery power. Converters are normally

voltage regulated to provide a constant supply of DC power and if the voltage is

high enough, partially recharge a battery. A manual battery charger is designed to

recharge a battery and typically produces higher voltages. An automatic or "smart"

battery charger is designed to stop charging when a preset current is achieved or

produce different voltages, depending on which charging cycle it is in. Battery

chargers typically do not have the degree of filtering that a converter has.









9.11. What Are Charge Controllers or Voltage Regulators?

101

Charge controllers and voltage regulators are devices used to control the level or

levels, in the case of three and four stage units, of DC voltage from a source of

power to the battery or batteries. Typically charge controllers are used to control

the output of solar panels and voltage regulators for DC generators or alternators.









9.12. How Long Will a Deep Cycle Battery Last On a Single Charge?



Discharging, like charging, depends on a number of factors such as the initial

State-of-Charge, average Depth-of-Discharge, condition and capacity of the

battery, load and temperature. To determine the amount of discharge time (T) for a

fully charged battery at 80° F (26.7° C), the simple formula is ampere-hour rating

(C) divided by the average load in amps (I) or T=C/I is often used. So, 100-ampere

hour battery with an average 5-amp load should last approximately 20 hours

(100/5). The total number of amps that are produced when a battery is discharged

over a 20 hour (C/20) period is the most commonly used specification for

expressing the capacity of deep cycle batteries used in most RV and Marine

applications; however, six hour (C/6) for Golf Carts or eight hour (C/8) rates for

RV/Marine batteries might be more realistic.



For example, if deep cycle battery's capacity is rated at 100 ampere hours (AH) at

the 20 hour (C/20) rate, will produce approximately 83 AH at the eight hour (C/8)

rate, 63 A in two hours (C/2), and 55 AH in one hour (C/1). This is due to the

Peukert Effect.



Repeatedly discharging a wet Low Maintenance deep cycle battery below 20%

State-of-Charge (approximately 12.0 volts) or shallow discharges of less than 10%

can significantly reduce the number of life cycles. Please see the graph on

average Depth-of-Discharge in Section 11.3. New batteries often require a

precondition or "break-in" period of up to 30 cycles before they will produce their

rated ampere hour capacity. The capacity is reduced overtime as the active

material flakes (sheds) off the plates and some of the pours fill with hard sulfate.









9.13. How Can I Reduce Recharging Time?



To reduce the amount of time that your charging system is running, only recharge

the battery to 80% State-of-Charge level at an amp hour rate not exceeding the

number of amp hours that need to be replaced or C/4 (25% of the AH Capacity),

whichever is less. For example, if 50 amp hours has been consumed from a 100

amp hour battery, then you do not want to recharge it at rate any greater than 25

amps in one hour. At a 25 amp charging rate, it should take approximately two

hours to get to a 80% State-of-Charge. Please note that it will take almost the

same amount of time, at a reduced current, to recharge the battery the remaining

20% to bring it to 100% State-of-Charge as it took to recharge it originally from the

102

50% to the 90% level. If the battery is recharged to the 80% State-of-Charge level,

it should be recharge to 100% at least every 10th cycle or once per week,

whichever occurs first.



Using AGM batteries also will reduce the amount of recharging time because they

have a higher acceptance rate than wet lead-acid batteries. Please see

Section 7.4 for more information.









9.14. How Can I Adjust the Specific Gravity?



Battery manufacturers set the concentration of the sulfuric acid in the electrolyte of

a fully charged wet battery to optimize the capacity, service life, water

consumption, use in float applications, high discharge rate capability, battery size

and self discharge rate. When the Specific Gravity is increased on purpose or by

additives, the following occurs: capacity, service life, water consumption, high

discharge rate capability, and self discharge rate are increased and use in float

applications and battery size decrease. When you decrease the Specific Gravity,

the reverse occurs. You might ask why increasing the Specific Gravity on wet

starting and motive deep cycle batteries is not a good thing? The answer is that it

also accelerates the corrosion of the positive plate grids and connecting straps

and you could have a premature battery failure; thus effecting overall service life,

but clearly there might be some short termed gains at the expense of increased

watering and service life.



Normally, unless there is a spill, battery acid should never be added to a battery. If

the temperature compensated Specific Gravity reading needs to be increased in a

cell for whatever reason, remove a small amount of some the existing electrolyte

and replace it with fresh battery acid with a 1.300 Specific Gravity. Repeat the

process until the cell matches the Specific Gravity readings of the rest of the cells

or, if the battery is fully charged, the manufacturer's temperature compensated

recommended value for a fully charged cell. If the temperature compensated

Specific Gravity reading needs to be decreased in a cell for whatever reason,

remove a small amount of some the existing electrolyte and replace it with

distilled, deionized or demineralized water. Repeat the process until the cell

matches the Specific Gravity readings of the rest of the cells or, if the battery is

fully charged, the manufacturer's temperature compensated recommended value

for a fully charged cell. Some typical Specific Gravity readings at 80° F (26.7° C)

for full charged cells are:



 1.300-1.310 for wet motive deep cycle batteries with tubular positive

plates



 1.267-1.284 for wet motive Deep Cycle batteries with solid lead

positive plates



 1.260-1.270 for wet Starting batteries with pasted plates



103

 1.215-1.250 for wet stationary Deep Cycle batteries with solid lead

positive plates









9.15. How Do I Recharge Small SLA Batteries?



SLA or Sealed Lead Acid batteries or part of the VRLA Battery class and are

normally under 50 amp hours in capacity. Most of the SLA batteries in use today

are AGM because they are less expensive, but there are a few gel cell SLA

batteries in service. For fast recharging, you should limit to the current to 30% of

the amp hour capacity of the battery and use an absorption voltage of 2.45

VDC/cell or 14.7 VDC or a 12-volt battery. When the charging current has dropped

to .01 times of the amp hour capacity, then the battery is fully charged and the fast

charging voltage should removed or reduce it to a float charging voltage of 2.25

volts/cell or 13.5 VDC for a 12-volt battery.









9.16. How Do I Recharge Unevenly Discharged or Non-identical Batteries at the Same

Time?



If discharging the batteries unevenly or using non-identical batteries has to occur,

then use an isolated multi-bank charger, single bank charge with an external diode

isolator (adjusted for the voltage loss), or combiner to recharge the batteries at the

same time.









104

10. WHAT CAUSES MY BATTERY TO DRAIN OVERNIGHT?



Last Updated on December 25, 2005





Parasitic (or ignition key off) drain is the cumulative load produced by electrical devices, for

example, emissions computers, clocks, security alarms, radio presets, etc., that operate

continuously after the engine is stopped and the ignition key has been switched off. Normal

parasitic loads are below 75 milliamps (.075 amps). When the parasitic load is greater than

75 milliamps (.075 amps), batteries will drain more quickly. Glove box, trunk, and under hood

lights that do not automatically turn off when the door is closed or shorted diodes in alternators

are the most common offenders. Cooling fans, power seat belt retractors, radios and dome

lights left on, alarm systems, and electric car antennas have also caused batteries to drain

overnight. Leaving your headlights on will generally discharge a fully charged car battery, with

90 minutes of Reserve Capacity (36 amp hours), within a couple of hours.



It is highly recommended, especially if you are using a sealed wet "Maintenance Free" (Ca/Ca)

battery, allow to thaw if frozen, fully recharge it in a well ventilated area with an external battery

charger, remove the surface charge, and load tested both the battery and the charging system

for latent damage from the deep discharge. You could have a damaged or bad battery. If the

alternator is warm and the engine is cold, then check for a shorted diode in the alternator.



Below are some methods that are used to test the parasitic load with the engine NOT running,

under hood light disconnected, all accessories switched off, and the vehicle doors closed:



 Connect a 12-volt bulb across the positive and negative battery

terminals to test the bulb and the battery. If it glows brightly, then

remove the negative battery cable and connect the bulb in series

between the negative battery cable terminal clamp and the negative

battery terminal. If the bulb continues to glow brightly, then start

removing fuses or connections to the positive battery post one-at-a-

time until the offending electrical component is identified by the bulb

dimming.



 A better approach is to use a DC ammeter, for example a Fluke 175,

inserted in series with the negative battery cable terminal clamp and

the negative battery terminal or a clamp-on DC ammeter, like a Fluke

336 or i410 around the negative battery cable. Starting with the

highest scale, determine the current load. If the load is above 75

milliamps (.075 amps) after the initial surge, then start removing

fuses or connections to the positive battery post one-at-a-time until

the offending electrical component is identified by the parasitic load

dropping to within 75 milliamps (.75 amps).



 Additional troubleshooting techniques can be found in a guide from

Exide at

http://www.exide.com/products/trans/na/battery_care/electrical_para

sitic_load.pdf.



105

11. CAN I INCREASE THE LIFE OF MY BATTERY?



Last Updated on February 26, 2005





The most important consideration in increasing the overall service life of a lead-acid battery is

preventive maintenance. Please see Section 3 for more information on preventive

maintenance. The typical life of a good quality, well maintained and properly charged battery is:



EXPECTED BATTERY SERVICE LIFE



Pasted Plate Car 0 to 12

(used as a Deep months

Cycle)

Pasted Plate Car 4 to 5

years

Pasted Plate to 4 years

Marine/RV

Solid Plate Golf Cart to 6 years

Gel Cell VRLA to 8 years

AGM VRLA to 8 years

Ni-Cad to 10

years

Calcium to 10

Telecommunications years

(Stationary)

Fork Lift (Motive) to 10

years

Manchex Industrial to 15

(Motive) years

Wet Standard to 20

(Sb/Sb) Industrial years

(Stationary)

Ni-Fe to 20

years





Here are some tips to increase car or deep cycle battery service life:



11.1. Protect your car battery from high underhood temperatures with a heat shield or case,

keeping it full charged at all times, and well maintained are the easiest ways to extend

it's life. In hot climates and during the summer, the electrolyte levels need to be checked



106

more frequently. In a study conducted by the Society of Automotive Engineers (SAE), the

underhood temperature has increased more than 30% since 1985.



Chrysler studies have shown that relocating the battery outside the engine

compartment has increased the average OEM battery life by eight months.

Relocating the starting battery to the trunk or passenger compartment, as Mazda

did in their Miata a number of years ago, is becoming more popular by the car

manufacturers to protect the starting battery from the high underhood

temperatures. However, use sealed VRLA AGM or Gel Cell type batteries because

they normally do not produce gas when recharged or wet batteries vented to the

outside. If you use a gel cell as a starting battery, you might have to lower the

charging system voltages because they are very critical and to keep from

overcharging the battery.



For motive and stationary deep cycle batteries, temperature is equally as

important for extending the service life of the battery or battery bank. Common

sense and chemical intuition suggest that the higher the temperature, the faster a

given chemical reaction will proceed. Quantitatively this relationship between the

rate a chemical reaction proceeds and its temperature is determined by the

Arrhenius equation. Battery life, due to positive grid corrosion, is reduced by 50%

for every 18° F (10° C)rise in ambient temperature over 70° F (21.1° C).



11.2. Periodically check the State-of-Charge of car batteries. Based on your driving habits,

some vehicle charging systems undercharge the battery causing an accumulation of

Lead sulfate known as sulfation. This sulfation reduces the capacity of the battery. If the

battery is not fully charged, recharge it periodically with an external battery charges

matched to the battery type. Please see Section 9 for more information on charging and

chargers and Section 16 for more information on sulfation.



In addition to temperature, car battery life and the number of charge and discharge

cycles is dramatically influenced by the average State-of-Charge (SoC) as

reflected in the following graph:



Car Battery Life









107

[Source: Adverc Battery Management]



If possible in a well ventilated area and at room temperature, recharge a deep

cycle battery each day it is used and as soon as possible after each use. The best

way to prevent permanent lead sulfation when a starting or deep cycle battery (or

battery bank) is not in use, is to maintain it's State-of-Charge at 100% by

continuous float charging. If continuous float charging is not possible, recharge

before the State-of-Charge drops below 80%. Permanent sulfation kills

approximately 85% of all deep cycle and starting lead-acid batteries not in

weekly service. During hot weather, try and drive your vehicle at least once per

week and in cold weather, once every two weeks. This is because batteries are

perishable and the vehicle's parasitic (ignition key off) load and the natural self-

discharge drain the battery. When the battery is not fully charged, sulfation occurs

and the lead sulfate crystals will accumulate, harden and reduce the capacity of

the battery. The same phenomenon occurs when a battery is undercharged or

when electrolyte stratification occurs in larger wet lead-acid batteries. Please see

Section 16. for more information on sulfation.



11.3. Reducing the average DoD (Depth-of-Discharge), the inverse of SoC, by proper deep

cycle battery sizing will significantly increase a deep cycle battery life. For example, a

pasted plate wet battery with an average of 50% DoD will last twice as long or more as if

it is has an 80% average DoD. A 20% DoD average battery can last up to five times

longer than one with a 50% DoD average. Wet Golf cart batteries will typically have an

average 225 cycles at 80% DoD and 750 cycles at 50% DoD. For more information of the

"50% Rule", please see Chris Gibson's article on

http://www.smartgauge.co.uk/50percent2.html. Always avoid DoDs that are greater than

80%. The "sweet spot" (optimum DoD for the greatest amount of power produced over

the service life) is generally somewhere between 20% DoD and 60% DoD average. For

the AGM battery example below the "sweet spot" is approximately 22.5% DoD based on

the greatest amount of power produced.

108

AGM Life Cycles vs. Percent Depth-of-Discharge (DoD)









[Source: Concorde]



11.4. Never discharge any 12-volt lead acid battery below 10.5 volts because it can damage

the battery. An adjustable low voltage disconnect set for an 80% Depth-of-Discharge

(DoD) or less can limit the maximum DoD and protect the batteries and electrical

appliances. Leaving your lights or other accessories on and fully discharging a car battery

can ruin it due to "cell reversal", especially if it is a sealed, wet Maintenance Free (Ca/Ca)

type. Deep discharges in freezing weather will cause the battery to freeze and the

expansion of the electrolyte can damage the plates, separators or even crack the battery

case. If freezing should occur, you must let your battery thaw, physically inspect case for

leakage, fully recharge it with a "smart" or "automatic" external charger matched the the

battery type in a well ventilated area, remove the surface charge, and load test the

battery and charging system to determine if there is any latent or permanent damage.



11.5. In extremely cold climates, keep the car battery continuously fully charged when not

in use, the engine and battery warm, and use low viscosity synthetic engine oil. AGM or

Ni-Cad batteries work better in sub-zero temperatures than wet lead-acid batteries.



11.6. In hot climates use the "hot climate or "South" versions of car batteries. They have

special plate and connecting strap formulations, lower Specific Gravity levels or

increased the amounts of electrolyte to provide more "cooling" for longer service life.

Using non-sealed Low Maintenance (Sb/Ca) car batteries is encouraged because you

can add water. "Watering" is required more often in hot climates and add only distilled,

demineralized or deionized water or, in a emergency, rain water. The plates must be

covered at all times to prevent an internal battery explosion or sulfation. Do not overfill,

and keep the top of the battery clean. Do NOT add electrolyte (battery acid) to a battery

unless some electrolyte has spilled. If the Specific Gravity levels are increased beyond

the battery manufacturer's recommended limit, there will be a higher capacity level, but





109

more maintenance and a shorter service life. Please see Section 9.14 for more

information on adjusting Specific Gravities.



11.7. Turning off all unnecessary accessories, rear window heater, climate control, and lights

before starting your car will significantly decrease the load on the battery while cranking,

especially when it is extremely cold.



11.8. Reducing the parasitic (key-off) load to below 75 milliamps.



11.9. In cold climates, increasing the diameter of the battery cables will reduce the voltage

loss.



11.10. If required, equalize wet (flooded) and some AGM batteries. Equalizing can also

prevent electrolyte stratification, which can cause sulfation. Please see Section 9. for

more information on equalizing batteries.



11.11. For vehicles not used weekly or driving habits that cause undercharged batteries,

continuously float charge the car battery or fully recharge it periodically to remove the

accumulated lead sulfate. Please see Section 13 for more information on storing batteries

and Section 16 for more information on sulfation.



11.12. Provide adequate ventilation. High ambient temperatures above 80° F (or 26.7° C)

will shorten battery life because it increases positive grid corrosion, growth and VRLA

"thermal runaway".



11.13. Recharging slowly using the battery manufacturer's recommended temperature

compensated voltages and procedures.



11.14. Avoid shallow (below 10%) discharges of deep cycle batteries because lead dioxide

builds up on the positive plates. In other words, you should discharge a deep cycle

battery between 10% and 80% Depth-of-Discharge.



11.15. Use batteries with thicker pasted or solid plates, thicker or tampered grids, and

reduce the number of discharge-charge cycles. Each cycle removes a microscopic layer

from the grid. Eventually the upper portion of the grid can not carry the current.



11.16. Apply the correct battery type for the application, that is, starting for starting

applications, motive deep cycle batteries for motive, and stationary deep cycle batteries

for stationary applications. Please see Section 7.1 for more information on battery types.









110

12. WHAT ARE THE COMMON CAUSES OF PREMATURE BATTERY FAILURES?



Last Updated on February 26, 2005





Normally, premature battery failures are caused by one or more of the failures listed below with

water loss and sulfation the main offenders. Prior to 1980, plate or grid shorts were the most

common failure. Since then the manufacturers have significantly improved the life expectancy

by using improved separators, plate alloys to reduce corrosion, and heat shields. By relocating

batteries to the passenger compartment (or trunk), also has considerably decreased premature

battery failures. Batteries that have been in use for longer periods of time will typically fail from

multiple causes. All batteries will fail at some point in time from old age (positive plate

shedding of active material or grid corrosion).









[Source: Interstate Batteries]







12.1. For wet car batteries, lack of preventive maintenance, high underhood heat, fast

recharging (greater than C/4), or overcharging causes a loss of water, account for over

50% of the failures. For wet motive and stationary deep cycle batteries, water loss due to

the lack of preventive maintenance or overcharging. Please see Section 3 for more

information on preventive maintenance.



12.2. Sulfation from water loss, undercharging, electrolyte stratification (especially in larger

batteries over a 100 amp hours), using tap water, excessive temperatures, or prolonged

periods of non-use account for approximately 85% of the deep cycle and starting battery

failures that are not used weekly (or bi-weekly in colder climates). Some vehicle charging

systems based on driving habits (short trips or high loads) leaving the car battery



111

constantly undercharged and sulfated. Please see Section 16 for more information on

sulfation.



12.3. Battery post or terminal corrosion, which cause a charging and discharging problems.

Please see Section 3 for more information on preventive maintenance.



12.4. High ambient temperatures above 77° F (25° C) causing accelerated positive grid

growth or corrosion, increased self-discharge, or thermal runway in VRLA (AGM and Gel

Cell) batteries. For every increase of 15° F above 77° F, a VRLA (AGM and Gel Cell)

battery's life is cut in half.



12.5. Excessive deep discharges below 10.5 volts, such as leaving your vehicle's lights on.



12.6. Misapplication, for example, using a starting battery in a deep cycle application, a

motive deep cycle battery instead of a stationary for a UPS, or an undersized battery (or

battery bank) that causes discharges greater than the battery was designed for or will not

produce enough capacity.



12.7. Plate-to-strap shorts due to excessive vibration caused by loose hold down clamps or

vehicle running surfaces or freezing.









112

13. HOW CAN I STORE BATTERIES?



Last Updated on December 26, 2005





INDEX:



13.1. How Do I Prevent Permanent Sulfation?



13.2. So How Do I Store My Battery?



All lead-acid batteries are perishable. If not used weekly, people kill more deep cycle and

power sport batteries with bad charging and maintenance practices, than die of old age!



When a lead-acid battery is discharged, soft lead sulfate crystals are formed in the pores and on

the surfaces of the positive and negative plates. When left in a discharged condition or

excessive high temperatures, is continually undercharged, or the electrolyte level is below the

top of the plates or stratified, some of the soft lead sulfate re-crystallize into hard lead sulfate.

These crystals cannot be reconverted during subsequent recharging. This creation of hard

crystals is commonly called permanent "sulfation". It is the leading cause and accounts for

approximately 85% of the premature failures of lead-acid batteries not used on weekly basis.

The longer sulfation occurs, the larger and harder the lead sulfate crystals become. The positive

plates will turn a light brown and the negative plates will be dull, off white. These permanent

crystals lessen a battery's capacity and ability to be recharged or hold a charge. Sulfation

primarily occurs in deep cycle and power sport batteries that are typically used for short periods

and then are stored for long periods where they slowly self-discharge. Whereas, a car or

motorcycle starting battery is normally used several times a month, so permanent sulfation

rarely becomes a problem unless it is unused or stored for long periods.



While a battery is in storage or not being used, the discharge is a result of parasitic load or

natural self-discharge. Parasitic load is the constant electrical load present on a battery while it

is installed in a vehicle even when the ignition key is turned off. The load is from the continuous

operation of electrical appliances, such as an emissions computer, clock, security system,

maintenance of radio station presets, etc. While disconnecting the negative battery cable will

eliminate the parasitic load, it has no affect on the natural self-discharge of battery. Thus,

permanent sulfation can be a huge problem for lead-acid batteries while sitting for long periods

on a dealer's shelf, in a basement, cellar, barn or garage, or in a parked vehicle, especially in

hot temperatures.



13.1. How Do I Prevent Permanent Sulfation?



Please see Section 16.2 for more information on preventing sulfation.









13.2. So How Do I Store My Battery?



113

Batteries naturally self-discharge 1% to 60% per month (depending on the

battery type and temperature) while not in use. Sulfation will begin occurring

when the State-of-Charge (SoC) drops below 100%. Please see Section 16

for more information on sulfation. Cold will slow the process down and heat

will increase it up. Storing batteries under 250 AH on concrete floors will not

cause them to naturally self-discharge faster. Please see Section 14.1 for

more information on this myth. Below are six simple steps while your

batteries are not in use to protect them from permanent sulfation and

premature failure.



13.2.1. Physically inspect for leakage or damaged cases, remove any corrosion,

clean and dry the tops of the batteries to remove possible discharge paths from

dried battery electrolyte, and clean the terminals. If the battery is in a vehicle,

remove the negative connection from the battery to eliminate the additional

parasitic (key off) discharge.



13.2.2. If the battery has filler caps, check the electrolyte (battery acid) level in each

cell. If required, add only distilled, deionized or demineralized water to the

recommended level, but do not overfill.



13.2.3. Fully charge and equalize wet (flooded) batteries, if required, using the

procedures in Section 9 and recheck the electrolyte levels when the battery

cools.



13.2.4. Store in a cold dry place, but not so that it will freeze, and where it can be

easily recharged. The freezing point of a battery is determined by the SoC and

the higher it is, the lower the freezing temperature. Please see the State-of-

Charge Tables in Section 4. Based on the battery type you are using, connect a

"smart", microprocessor based three stage or four stage charger or a voltage

regulated float charger to continuously "float" charge your battery. Do not use a

cheap, unregulated "trickle" charger or a manual two stage charger which was

not designed for "float" charging or you will overcharge your battery. A less

desirable alternative to float charging would be to periodically test the State-of-

Charge using the procedure in Section 4. When it is 80% or below, recharge

using the procedures in Section 9. The frequency of testing and recharging will

depend on the ambient storage temperature.



AGM BATTERY FLOAT CHARGING VOLTAGE









114

TEMPERATURE IN DEGREES C (F)



[Source: Concorde]



13.2.5. Periodically test the State-of-Charge (SoC) and ensure that the electrolyte is

at the proper levels.



13.2.6. When you remove the batteries from storage, charge and equalize, if

required, using the battery manufacturer's recommended charging procedures

or, if not available, the one in Section 9.









115

14. WHAT ARE THE MYTHS ABOUT BATTERIES?



Last Updated on January 6, 2006





INDEX:



14.1. Storing a battery on a concrete floor will discharge them.



14.2. Driving a car will fully recharge a battery.



14.3. A battery will not explode.



14.4. A battery will not lose its charge sitting in storage.



14.5. Wet "Maintenance Free" (Ca/Ca) batteries never require maintenance.



14.6. Test the alternator by disconnecting the battery with the engine running.



14.7. Pulse chargers, desulfators, aspirins or additives will revive sulfated

batteries.



14.8. On really cold days turn your headlights on to "warm up" the battery up

before starting your engine.



14.9. Car batteries last longer in hot climates than in cold ones.



14.10. Charging cables or jump starters will start your car.



14.11. A larger capacity battery will damage my car.



14.12. Lead-acid batteries have memories.



14.13. Bad batteries will not harm the charging system or starter.



14.14. Once formed, batteries will not change polarity.



14.15. Use tap water to refill batteries.



14.16. Driving to recharge a dead car battery.







14.1. Storing a battery on a concrete floor will discharge them.



All lead-acid batteries will naturally self-discharge which can result in loss of

capacity from sulfation. The rate of self-discharge is most influenced by the

temperature of the battery's electrolyte and the chemistry of the plates. This self-

116

discharge is often mistaken for concrete floor causing the battery to drain. Some

experts believe that storing car or deep cycle batteries on a colder concrete floor

might actually slow down the self-discharge (leakage) rate because the floor acts

as a heat sink and cools the battery. (Please see Section 13 for more information

on storing batteries and Section 1 for more information on sulfation.



In the early 1900s, when battery cases were made of porous materials such as

tar-lined wood boxes, storing batteries on concrete floor would accelerate their

natural self-discharge due to external leakage. Modern battery cases are made of

polypropylene or hard rubber. These cases are sealed better, so external leakage-

causing discharge is no longer a problem, provided the top of the battery is clean

and free from wet or dried electrolyte and the same temperature as the floor.



Large differences in temperature could cause electrolyte stratification within very

large batteries (>250 AH) which could accelerate it's internal "leakage" or self-

discharge if the battery is sitting on an extremely cold concrete, stone or steel floor

in a warm room, boat or submarine. Stirrers or bubblers are often used on these

types of large batteries to keep the electrolyte from stratifying. Undercharging will

also cause electrolyte stratification, which can also result in loss of capacity from

sulfation.









14.2. Driving a car will fully recharge a battery.



There are a number of factors affecting a vehicle charging system's ability to

recharge a battery, such as how much power and charging voltage from the

alternator is diverted to the battery, how long the power is available, and the

temperature. Generally, idling the engine or short stop-and-go trips during bad

weather or at night will not fully recharge a car battery or will leave your battery

undercharged which causes sulfation. When a dead battery needs to be

recharged, it is best to use an external battery charger because you could over

heat and damage your vehicle's charging system and your will save a lot of gas

and wear and tear on your engine. Please see Section 5 and Section 9 for more

information on vehicle charging systems and charging.









14.3. A battery will not explode.



Charging a wet lead-acid battery naturally produces hydrogen and oxygen gasses

as electrolysis of the water occurs and needs to occur in well ventilated areas.

While spark retarding vent caps help prevent external battery explosions, sparks

occur when jumping, connecting or disconnecting charger or battery cables and

ignite the gas causing an explosion. From the U.S. Department of Energy, DOE-

HDBK-1084-95, "Precautions must be routinely practiced to prevent explosions

from ignition of the flammable gas mixture of hydrogen and oxygen formed during

117

overcharge of lead-acid cells. The maximum rate of formation is 0.42 L of

hydrogen and 0.21 L of oxygen per ampere-hour overcharge at standard

temperature and pressure. The gas mixture is explosive when hydrogen in air

exceeds 4% by volume." Less common internal explosions usually occur while

starting the engine or using the battery and normally just blow the filler caps or

cover off the battery and splatter electrolyte all over the engine compartment or

battery box.



The most probable cause of internal battery explosions are from a combination of

low electrolyte levels below the plates in the battery, a low resistance bridge is

formed between or across the top of the plates, and a build up of hydrogen gas in

the cell. The low resistive bridge is called "treeing" between the positive and

negative plates. When current flows in the battery, a spark occurs and ignites the

residual gas in one or more of the cells. A second possible cause is a

manufacturing defect in the weld of one of the plate connecting straps causing a

spark igniting the residual gas. Another source of internal battery explosions are

caused from direct electrical shorts across the battery's terminals. The battery

rapidly over heats form the high current and can explode. The largest number of

internal battery explosions occur in hot climates due to the loss of water while

starting the engine. Most internal battery explosions could have been prevented if

the plates were always covered with electrolyte. Please see Section 3 for more

information preventive maintenance.



A less common form of internal battery explosion occurs when a dead short is

applied across the battery terminals or the battery is in a fire.









[Source: Popular Mechanics]







118

Periodic preventive maintenance (Please see Section 3.), working on batteries in

well-ventilated areas, or using sealed AGM or Gel Cell type batteries can

significantly reduce the possibility of battery explosions. To neutralize residual

battery acid, be sure to thoroughly wash the engine compartment and the back of

the hood with a solution of one-pound baking soda (bicarbonate of soda) to one

gallon of warm water and rinse thoroughly with water. While not fatal, each year

battery explosions cause thousands of eye and burn injuries from the electrolyte

(battery acid). According to PREVENT BLINDNESS AMERICA, last year (2003)

nearly 6,000 motorists suffered serious eye injuries from working around car

batteries. Should a battery explosion occur and battery electrolyte (battery

acid) gets in someone's eyes, flush them out with any drinkable liquid

immediately because SECONDS count, continue flushing with water for at

least 15 minutes, and seek immediate medical attention.









14.4. A battery will not lose its charge sitting in storage.



Depending on the type of battery and temperature, batteries have a natural self-

discharge or internal electro chemical "leakage" at a 1% to 60% rate per month.

Over time the battery will become sulfated and fully discharged which make it

more susceptible to freezing. Higher temperatures will significantly accelerate this

process. A battery stored at 95° F (35° C) will self-discharge twice as fast than one

stored at 75° F (23.9° C). Leaving a battery in a vehicle can increase the discharge

of battery due to the additional parasitic (ignition key-off load), unless the negative

cable is disconnect from the battery. (Please see Section 15 and Section 16 for

more information on parking times and sulfation.)









14.5. Wet "Maintenance Free" (Ca/Ca) batteries never require maintenance.



The term "Maintenance Free" generally refers to a wet, sealed lead-acid car and

deep cycle batteries with calcium positive and negative plates. (Please see

Section 7.1.3 for more information on these types of batteries.) In hot climates, the

water is lost due to evaporation the high underhood temperatures and the normal

charging process. Water can also be lost due to excessive charging voltage or

charging currents. Using non-sealed wet Low Maintenance (Sb/Ca) batteries (with

filler caps) are encouraged in hot climates so distilled, deionized or demineralized

water can be added when this occurs. (Please see Section 3. for other preventive

maintenance procedures that should be performed on wet "Maintenance Free"

(Ca/Ca) batteries.)









14.6. Test the alternator by disconnecting the battery with the engine running.

119

A battery acts like a voltage stabilizer or filter to the pulsating DC produced by the

alternator. Disconnecting a battery while the engine is running could destroy the

sensitive electronic components connected to the electrical system such as the

emission computer, radio, audio system, cell phone, alarm system, etc., or the

charging system, especially with internal voltage regulators, because the peak

voltage can rise to 40 volts or more. In the 1970s, removing a battery terminal was

an accepted practice to test charging systems of that era. That is not the case

today. Static electricity and spikes from connecting and disconnecting batteries or

test equipment could also damage sensitive electronic components.









14.7. Pulse chargers, desulfators, aspirins or additives will revive sulfated batteries.



Using pulse chargers, desulfators or additives are very controversial subjects.

Despite claims of the charger manufacturers, some battery experts believe that

there is no conclusive proof that pulse chargers work any better than constant

voltage chargers to remove permanent or prevent sulfation. Most agree that there

is no evidence that additives or aspirins provide any long-term benefits. Short

term gains are achieved by increasing the acidity (Specific Gravity) of the battery,

which could increase the Amp Hour capacity, but increase the water consumption

and positive grid corrosion and will decrease the overall service life of the battery.

After a heavy discharge, allowing a battery to rest will regain some of its capacity

as the electrolyte has an opportunity to diffuse in the pores of the plates.



The the controversy between the additive manufacturers, battery manufacturers,

and independent elecrochemists has been going on for years as demonstrated in

this AD-X2 Battery Additive, From a Trickle to a Torrent article form the National

Institute of Standards and Technology (NIST) Museum.









14.8. On really cold days turn your headlights on to "warm up" the battery up before

starting your engine.



While there is no doubt that turning on your headlights will increase the current

flow in a car battery, it also consumes valuable capacity that could be used to start

the cold engine. Therefore, this is not recommended. For cold temperatures,

externally powered temperature compensated battery "float" chargers, warmers or

blankets, and engine block heaters are highly recommended if the vehicle can not

be parked in a heated garage. AGM and Ni-Cad batteries will perform better than

wet lead-acid batteries in extremely cold temperatures.









14.9. Car batteries last longer in hot climates than in cold ones.

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Car batteries last an average of two thirds as long in hot climates as cold ones.

Heat kills car batteries, especially sealed Maintenance Free (Ca/Ca) batteries, and

cold reduces the battery's starting capacity. (Please see Section 11.1 for more

information on increasing battery life.)









14.10. Charging cables or jump starters will start your car.



The cigarette lighter charging cable's advertising states "charges weak batteries in

minutes." There is little doubt that charging cable products will certainly recharge

your car battery if you have enough time and your battery is in good condition.

Cigarette lighters are normally fused at 10 amps, so to be safe they probably limit

current flow less that the fuse size. Given the diameter of the wire used in the

cable, the amount might be even less.



They work by applying higher voltage from the vehicle with the good battery to

"charge" the bad one. In order to charge a battery the charging voltage need to be

approximately two volts greater than the the battery voltage to overcome the

internal resistance. Now let's assume it is a hot day and that you need just of 3%

of the battery's capacity to start the engine from a 40 amp hour battery. This

means you will need at least 7.5 amps for 10 minutes to flow from the good battery

with the engine idling to the bad one. Now let's also assume that it is below

freezing and you have left your lights on. You will need at least 50% capacity or

20 amp hours to start the vehicle. This will take over two hours to partially charge

the dead battery. Using jumper cables with the engine running at high idle will

partially charge a dead battery much faster. Please see Section 6 for jump

starting, but be sure the battery is not frozen or the case is cracked.



Some auto jump starter uses special high current batteries to provide up to 900

peak amps to start your engine. It can provide 200-300 amps for up to 8-10

seconds. Standard AA alkaline batteries are used to trickle charge the special

batteries to maintain their charge. This type of emergency starter should start all

but diesel engines up to six or eight times on one charge, depending on the

capacity of the battery, condition of the engine and the temperature. After this, the

jump starter should be recharged for 24 to 48 hours.









14.11. A larger capacity battery will damage my car.



A starter motor will only use a fixed amount of current from the battery, based on

the resistance of the motor. A larger CCA, RC or AH capacity battery supplies

only what is required. It will not damage your vehicle; however, using batteries

with higher or lower voltage or physically too high could potentially cause harm.





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14.12. Lead-acid batteries have memories.



Lead-acid batteries do not have the "memory effect" mistakenly identified with first

generation Ni-Cad batteries; however, continuous undercharging will lower the

capacity of the battery over time due to the accumulation of permanent lead-

sulfate or "sulfation". Deep discharges below twenty percent State-of-Charge

(approximately 12.0 volts) can damage batteries and will shorten their service

lives.









14.13. Bad batteries will not harm the charging system or starter.



A bad or weak starting battery causes additional stress on a charging system,

starter motor or starter solenoid. It can cause premature failures due to

compensating for the voltage or current. If you replace a battery, alternator,

voltage regulator or starter, you should test the other components for damage and

repair or replace them as required.









14.14. Once formed, batteries will not change polarity.



If a battery is fully discharged and continues to have a load, for example leaving

the headlights on, it is possible for one or more cells to reverse polarity. When the

battery has been recharged with reversed polarity the polarity can change. This is

referred to as "cell reversal". To change polarity, fully discharge the battery and

recharge it with the correct polarity.









14.15. Use tap water to refill batteries.



Use only distilled, deionized or demineralized water to replace the lost water in

batteries because using tap or reverse osmosis water from residential systems

can produce calcium or magnesium sulfate crystals that can fill the pores and coat

the plates. In an emergency, use rain water because rain water does not contain

calcium or magnesium.









14.16. Driving to recharge a dead car battery.



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If jump starting is required to start an engine, the battery should be fully charged

by an external charger and then tested for latent damage. Assuming that a car

battery has a 50 amp hour capacity and the vehicle's charging system is capable

of producing 50 amps at highway speeds, it would take approximately 120 minutes

to fully recharge a good battery. If the battery is frozen, it is best to temporarily

install another fully charged battery until the original battery can be thawed out,

fully recharged and tested. Vehicle charging systems are not designed to recharge

fully discharged batteries and doing so may damage the stator or the diodes from

overheating.









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15. HOW LONG CAN I PARK MY VEHICLE?



Last Updated on December 25, 2005





The amount of time, usually referred to as "airport", "garage", or "storage" time, that you can

leave your vehicle parked and still start your engine is dependent on such things as the battery's

initial State-of-Charge (SoC), the Reserve Capacity, the amount of natural self-discharge and

parasitic (ignition key off) load, temperature and battery type (plate chemistry). Car

manufacturers normally design for at least 14 days or more "airport" time; based on a fully

charged battery in good condition, moderate weather, and no additions to the original car's

parasitic load (for example, an after market alarm system). The number of days will vary based

on the temperature. When a battery drops below 100% SoC, sulfation starts slowly occurring,

and this will reduce the capacity of the battery, and left unchecked, will kill the battery.



If you leave your vehicle parked for more than two weeks, then you have several options:



15.1. The best long term (over one month) option is to continuously float charge your car

battery in a well ventilated area by connecting a "smart" battery charger, voltage

regulated float charger, or 5 watt or greater solar float charger. You will need a "float"

charging voltage between 13.2 and 13.8 VDC at 80° F (26.7° C) and at least .5 amps

(500 milliamps) to overcome the vehicle's parasitic load and the natural self-discharge of

the battery. Do not use a cheap "trickle" charger, because it will overcharge your battery

and dry out the electrolyte. This option will allow you to park you vehicle indefinitely, but

the battery should be checked periodically.



15.2. Disconnect the NEGATIVE (-) battery cable to remove the parasitic load, but be sure

that you have saved any security codes or radio stations presets that will have to be

reprogrammed, but the battery's natural self-discharge will continue. This option will

work from one month to six months depending battery type and temperature.



15.3. Replace the battery with the largest VRLA AGM or Spiral Wound AGM type battery that

will fit, e.g., an Optima or Exide Select Orbital, with very low self-discharge rates. For

periods greater than two months, also disconnect the NEGATIVE (-) battery cable to

remove the parasitic load. This option will work for six months to twelve months

depending battery type and temperature.



15.4. Install a battery with a larger reserve capacity or connect an identical battery in parallel,

but the battery's natural self-discharge will continue. For periods greater than two

months, also disconnect the NEGATIVE (-) battery cable to remove the parasitic load.

This option will work for two months to twelve months depending battery type and

temperature.



15.5. Replace the battery when you are ready to drive the vehicle again, especially if the

battery is over three years old and in a hot climate.



15.6. Have someone drive your car during the day at highway speeds every two weeks for at

least 15 minutes to keep the battery charged.



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15.7. Jump start the battery and hope that there is no latent damage.



15.8. Install a low voltage disconnect. This is especially helpful if the driver forgets to turn the

headlights off.









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16. HOW CAN I REVIVE A SULFATED BATTERY?



Last Updated on December 28, 2005





INDEX:



16.1. How Can I Tell If my Battery Has Permanent Sulfation?



16.2. How Do I Prevent Permanent Sulfation?



16.3. How Do I Recover Sulfated Batteries?



16.4. Where Can I Find Additional Information On Sulfation?



People kill more deep cycle batteries with poor charging practices, than die of old age!



Lead sulfation actually starts when you remove the charging voltage a full charged lead-acid

battery. The lead sulfate crystals are converted back to lead during the normal charging cycle.

The real question is, if all of the lead sulfate crystals are not turned back into lead, how long

does it take before they become so hard that they can not be converted? The answer is that

varies--it could be weeks or months and depends on a number of factors such as the quality of

the lead, temperature, plate chemistry, porosity, Depth-of-Discharge, electrolyte stratification,

and so on.



During the normal discharge process, lead and sulfur combine into soft lead sulfate crystals are

formed in the pores and on the surfaces of the positive and negative plates inside a lead-acid

battery. When a battery is left in a discharged condition, continually undercharged, or the

electrolyte level is below the top of the plates or stratified, some of the soft lead sulfate re-

crystallizes into hard lead sulfate. It cannot be reconverted during subsequent recharging. This

creation of hard crystals is commonly called permanent or hard "sulfation". When it is present,

the battery shows a higher voltage than it's true voltage; thus, fooling the voltage regulator into

thinking that the battery is fully charged. This causes the charger to prematurely lower it's output

voltage or current, leaving the battery undercharged. Sulfation accounts for approximately 85%

of the lead-acid battery failures that are not used at least once per week. The longer sulfation

occurs, the larger and harder the lead sulfate crystals become. The positive plates will be light

brown and the negative plates will be dull, off white. These crystals lessen a battery's capacity

and ability to be recharged. This is because deep cycle and some starting batteries are typically

used for short periods, vacations, weekend trips, etc., and then are stored the rest of the year to

slowly self-discharge. Starting batteries are normally used several times a month, so sulfation

rarely becomes a problem unless they are undercharged or the plates are not covered with

electrolyte.



As a consequence of parasitic load and natural self-discharge, permanent sulfation occurs as

the lead-acid battery discharges while in long term storage. (Parasitic load is the constant

electrical load present on a battery while it is installed in a vehicle even when the power is

turned off. The load is from the continuous operation of appliances, such as a clock, security

system, maintenance of radio station presets, etc.) While disconnecting the negative battery



126

cable will eliminate the parasitic load, it has no effect on the natural self-discharge of a car

battery. Self-discharge is accelerated by temperature. Thus, sulfation can be a huge problem for

lead-acid batteries not being used, sitting on a dealer's shelf, or in a parked vehicle, especially

in HOT temperatures.



Car and deep cycle lead-acid batteries are perishable!



16.1. How Can I Tell If my Battery Has Permanent Sulfation?



Chances are that your battery has some permanent sulfation, if it will not "take" or

"hold" a charge and exhibits one or more of the following conditions:



 If your wet (flooded) Standard (Sb/Sb) or wet (flooded) Low

Maintenance (Sb/Ca) battery has been not been recharged for over

three months, especially if the temperature in the storage area was

consistently over 77 degrees F (25 degrees C). (Six months for wet

Maintenance Free (Ca/Ca) or one year for VRLA AGM or Gel Cell.)



 While recharging in a well ventilated area, the ammeter does not

drop to below 2% (C/50) of the twice the amp hour capacity of the

battery divided by the charging rate in hours and the battery is warm

or hot. For example, if you have a 50 AH battery and a ten amp

charger, a discharged battery should be fully charged within 10 hours

(2 x 50 AH/10 amps = 10 hours).



 If the Specific Gravity is low in all cells after the battery been on a

charger for a long time.



 If the temperature compensated absorption charging voltage is

correct and the battery is gassing or boiling excessively.



 Poor performance or low capacity.



 When the SoC measured by a hydrometer, which is more accurate,

does not materially agree with the SoC measured by a digital

voltmeter









16.2. How do I prevent permanent sulfation?



The best way to prevent sulfation is to keep a lead-acid battery fully charged

because lead sulfate is not formed. This can be accomplished three ways.

Based on the battery type you are using, the best solution is to use an external

charger in a well ventilated area that is capable of delivering a continuous,

temperature compensated "float" charge at the battery manufacturer's

recommended float or maintenance voltage for a fully charged battery. For 12-volt

batteries, depending on the battery type, usually have fixed float voltages between

13.1 VDC and 13.9 VDC, measured at 80° F (26.7° C) with an accurate (.5% or

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better) digital voltmeter. [For a six-volt battery, measured voltages are one half of

those for a 12-volt battery.] This can best be accomplished by continuously

charging using a three stage for VRLA (AGM or Gel Cell) batteries or four stage

for wet (flooded) batteries, "smart" microprocessor controlled charger. If you

already have a two stage charger, then use a voltage-regulated "float" charger or

battery "maintainer", set at the correct temperature compensated float voltage to

"float" or maintain a fully charged battery. If you need Web addresses or telephone

numbers of the charger manufacturers, please see the Chargers and Float

Chargers and Battery Maintainers sections of Battery Information Links List. A

cheap, unregulated "trickle" or a manual two stage charger can overcharge a

battery and destroy it by drying out the electrolyte.



A second method is to periodically recharge the battery when the State-of-Charge

drops to 80% or below. Maintaining a high State-of-Charge tends to prevent

irreversible permanent sulfation. The frequency of recharging depends on the

parasitic load, temperature, battery's condition, and battery type. Lower

temperatures slow down electrochemical reactions and higher temperatures will

significantly increase them. A battery stored at 95° F (35° C) will self-discharge

twice as fast than one stored at 75° F (23.9° C). Standard (Sb/Sb) batteries have a

very high self-discharge rate; whereas, AGM and Gel Cell VRLA batteries have

very low rates. Please see Section 7.1 for more information on battery types.



There are trade-offs between the economics of continuous "float" charging, where

self-discharge and resulting sulfation does not occur, and periodic charging with

the increased potential for a shorter battery life due to permanent sulfation. If you

decide to periodically recharging the batteries while in storage, increased

recharging frequency, disconnecting any parasitic load, or storing them in colder

temperatures will impede the self-discharge and reduce the possibility for

permanent sulfation, but will also reduce the total number of life cycles.



A third technique is to use a solar panel or wind or water generator designed to

"float" charge batteries. This is a popular solution when AC power is unavailable

for charging. The size of a solar panel or wind or water generator required will

depend on the average amount of available natural resource, battery capacity and

temperature. Normally a five watt or larger panel is required for an average car

battery. A charge controller (voltage regulator) is required when the peak current

output exceeds 1.5% of the amp hour capacity of the battery.



A desulfator may be used in conjunction with any of the above methods.









16.3. How do I recover sulfated batteries?



Here are some methods to try to recover permanently sulfated batteries:



16.3.1. Light Sulfation





128

Check the electrolyte levels and try one of the following three methods for

removing light sulfation:



16.3.1.1. Equalize the battery. Please see Section 9.1.4. for more

information on equalizing.



16.3.1.2. Apply a constant current at 2% of the battery's Reserve Capacity

or 1% of the Amp Hour capacity rating for 48 to 120 hours, depending on

the electrolyte temperature and capacity of the battery, at 14.4 VDC or

more, depending on the battery type. Cycle (discharge to 50% and

recharge) the battery a couple of times and test its capacity. You might

have to increase the voltage in order to break down the hard lead sulfate

crystals. If the battery gets above 125° F (51.7° C) then stop charging and

allow the battery to cool before continuing.



16.3.1.3. Use a desulfator also known as a pulse charger. A list of some of

the desulfator or pulse charger manufacturers is available on the Battery

References Links List at http://www.batteryfaq.org. Please note that despite

desulfator manufacturer's claims, some battery experts feel that desulfators

and pulse chargers do not work any better at removing permanent or

preventing sulfation than do constant voltage chargers.



16.3.2. Heavy Sulfation



Check the electrolyte levels and try one of the following two methods for

removing heavy sulfation:



16.3.2.1. Replace the old electrolyte with distilled, deionized or

demineralized water, let stand for one hour, apply a constant current at four

amps at 13.8 VDC until there is no additional rise in specific gravity, remove

the electrolyte, wash the sediment out, replace with fresh electrolyte

(battery acid), and recharge. If the specific gravity exceeds 1.300, then

remove the new electrolyte, wash the sediment out, and start over from the

beginning with distilled water. You might have to increase the voltage in

order to break down the hard lead sulfate crystals. If the battery gets above

125° F (51.7° C) then stop charging and allow the battery to cool down

before continuing. Cycle (discharge to 50% and recharge) the battery a

couple of times and test capacity. The sulfate crystals are more soluble in

water than in electrolyte. As these crystals are dissolved, the sulfate is

converted back into sulfuric acid and the specific gravity rises. This

procedure will only work with some batteries.



16.3.2.2. Use a desulfator also known as a pulse charger. A list of some of

the desulfator or pulse charger manufacturers is available on the Battery

References Links List at http://www.batteryfaq.org. Please note that despite

desulfator manufacturer's claims, some battery experts feel that desulfators

and pulse chargers do not work any better at removing permanent or

preventing sulfation than do constant voltage chargers.





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16.4. Where Can I Find Additional Information On Sulfation?



Please read Collyn Rivers' article, Battery Pulsing Devices. Here are some articles

on sulfation, desulfation and desulfators by Alistair Couper, Lead Acid Battery

Desulfation Pulse Generator; Some Technical Details on Lead Acid Batteries: The

Chemistry of Sulfation, and Why Pulsing Helps, and Desulfator Frequently Asked

Questions.









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17. WHY WON'T MY ENGINE START?



Last Updated on December 25, 2005





Finding the reason why your engine will not start can be a very frustrating problem. The battery

and starter motor's principal job is to start the engine. While the engine is running, the alternator,

voltage regulator and battery all work together to provide stable source of power for your vehicle

and to recharge the battery. All of these components, including the wiring and wiring

connections, must be in good working order to start and operate your engine.



Assuming you have the battery's plates covered with electrolyte, sufficient fuel, the engine and

ignition system are in good working order, and the electrolyte is not frozen, the following is a list

of four simple instructions on how to troubleshoot the problem and isolate the source:



1. If there are no lights or other strange electrical problems, CHECK the wiring, battery

terminal mating surfaces, inside the positive GM style side battery cable terminal with

multiple cables, and grounding strap between the engine and chassis for corrosion or

oxidation. Clean each end to bare metal. Loose, bad or corroded connections are very

common causes. If good, then



2. RECHARGE and TEST the battery for latent damage and TEST the charging system. If

good, then



3. Test the starter. Burned solenoid contacts, worn starter motor brushes or loose starter bolts

are common problems for older vehicles.



4. If the problem continues or the battery drains overnight, TEST for excessive parasitic

(ignition key off) drain.



Some auto parts or battery stores in the United States and Canada, like Auto Zone, Sears, Wal-

Mart, Pep Boys, etc., will test your battery, charging system and starter for free. Simple stuff,

like corrosion, bad or loose cable connections, loose alternator belt, loose starter bolts, or a

dead battery, can cause your car not start. If the problem is not corrected, take your vehicle to a

good auto electric shop is highly recommended.









131

18. WHERE CAN I FIND MORE INFORMATION ON BATTERIES?



Last Updated on December 25, 2005





Additional information on car and deep cycle batteries maybe found on the Web site at

http://www.batteryfaq.org/. For example, there is a frequently updated list list containing

hyperlinks to lead-acid battery manufacturer's sites, battery brand names, private labeling

information and telephone numbers. There are two lists with hyperlinks to battery related

product information and references about lead-acid batteries, for example, charging systems,

regulators, isolators, test and monitoring systems, associations, books, magazines, history,

directories, standards, etc. Also, there is a zipped (.zip) file of all documents and graphics

contains of this Web site. It can found at Battery.zip.



Most of the battery manufacturers have a Battery FAQ posted on their web sites in addition to

product information, specifications and charging voltages and procedures. Web addresses will

often change, so you can use an Internet search tool like http://www.google.com/,

http://www.yahoo.com/, http://www.msn.com/, etc. to locate the new addresses. These search

tools are very effective in finding specific topics as well.



I will be happy to try and answer your lead-acid battery and charging questions.

Historically, over 80% of the questions I receive have already been answered in the FAQ

posted on this Web site, so please check it first. Some of the e-mails I receive do not

have a valid return address, so please inclose a valid "Reply To:" e-mail address in your

message and include a "Subject:" that will not be blocked by your spam filter or firewall.

All e-mail received with a virus or worm will be automatically deleted. For comments,

suggestions or questions, please e-mail Bill Darden at info@batteryfaq.org or

william.darden@uumail.de.



I highly recommend that you hyperlink to http://www.batteryfaq.org/ rather than republishing this

document because this information will be revised weekly to keep up with the advancements in

batteries and the changing resources. Revisions will be indicated with a more recent date or

higher version number. These documents are in the public domain and can be freely

reproduced or distributed without permission. Attribution is always appreciated, but not required.









132

19. HOW CAN I PRINT THIS FAQ?



Last Updated on December 25, 2005





The intent of this page is to present ways you can print the documents posted on this Web site.

While hyperlinking to http://www.batteryfaq.org/ is highly recommended because it is frequently

updated, many of you would like a printed copy. Some have asked why the FAQ and supporting

documents were divided into smaller Web pages. The answer is because the FAQ was

becoming so large that some readers were experiencing time-outs when trying to view it while

using their dial-up Internet connection. The choice was between eliminating some of the

graphics or breaking up the FAQ into smaller pages. Also, there is a zipped (.zip) file of all

documents and graphics contains of this Web site. It can found at Battery.zip.



19.1. Printing or Saving With Graphics



 Open the Web pages using a word processing program, like

Microsoft Word, that supports .htm or .html files and use the

program's Print command. If you want to save the Web pages, copy

them into one document and used the Save As command. This is

especially useful when you want to concatenate or combine a

number of Web pages into one document.



 For example, in Internet Explorer, use your Web browser's Print or

Save As commands. They are under the File button in the upper left

hand corner of the Web page. Printing directly from your browser

could cause some portions of the pages to be cut off, so resizing

your pages to fit on your printer, reformatting, or printing in the

"landscape" mode is recommended.







19.2. Printing Without Graphics



 Use your Web browser's Save As command and save the Web page

as a text (.txt) file.



 Print the text file using a word processor, Notepad, Workpad, DOS

Print command, or a text editor.









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