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					       Gas2Electric - Electric Car Conversion Guide




Gas2Electric – Electric Car
   Conversion Guide




  www.Gas2Electric.net



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                                  Gas2Electric - Electric Car Conversion Guide



                                                         Electric Vehicle
                                                             Conversion

When converting a vehicle into an electric car, there are many things that need to be taken into
consideration; such as, if the conversion will benefit your lifestyle, if there is room for the conversion
to take place and what kind of car will work best for the conversion. This can be an expensive project
and so it is important to make sure the conversion will be worth the time, money and effort.

First, electric vehicles generally have a range of 30-70 miles a day depending on both the type of
battery and the weight of the car. Electric vehicles are perfect for average terrain and commutes that
do not exceed 35 miles one way. Charging the car is also something to think about because places like
town homes and parking garages may require permission to charge the car. Of course, actually
building the vehicle requires adequate space and proper tools. It is recommended that a garage or
driveway is available. The easiest and most efficient way to convert into an electric vehicle is to use a
kit. Although they can be costly, it will actually save in the long run because all the parts are available
and many of them are complete with instruction manuals. Other tools such as torque wrenches, cable
crimpers and engine cranes can all be rented cheaply.




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                                 Gas2Electric - Electric Car Conversion Guide




                                                              Skills Needed

A wide range of skills is needed by a converter of a vehicle. Fortunately, there will often be fellow EV
enthusiasts in an area that are willing and able to assist the novice builder.

Basic mechanics

A builder should be able to fabricate small brackets for mounting sensors, switches, and relays. This
can be done using simple hand tools - a small vice, hacksaw, shears, hammer, pliers, and various drills
and files.

Machine shop skills

Most machining requires expensive equipment and extensive skills. Machine shop skills will not be
needed if the converter can obtain "off the shelf" components (components made to order from known
specifications). In the case of exotic conversions the converter may have to have specialized work
done locally, or ship the transmission to a specialty vendor. The more machine shop skills a builder
has the more work that builder will be able to perform, and will be more skilled at selecting
professional help. Creation of the motor coupling and the motor to transmission adapter usually
require skills and experience of a high order (a typical automotive machinist will not usually be able to
perform the work satisfactorily). A knowledgeable converter will be better able to judge the
qualifications of the machinist to be employed, and a cooperative machinist may be willing to allow
the converter to perform some of the lower skilled and lower risk tasks. It is also important that the
machine shop tasks be well planned out and broken down into the component subtasks, something that
a converter of modest machine shop skills will be able to do. Work in a machine shop may be done at
fixed price (in which case the enumeration of tasks will aid in bid preparation) or performed using an
hourly rate, in which case the estimate will be more accurate. For an exotic conversions where
components must be designed a good relationship with a cooperative machine shop is essential to
completing a successful and cost-effective project.




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                                 Gas2Electric - Electric Car Conversion Guide
Welding

For conversion of a unit body vehicle it is especially important that the batteries be well secured. This
is typically done by creating racks from angle steel stock or boxes from sheet metal welded into forms
suitable for the batteries and vehicle. These racks or boxes are then welded to the unit body or secured
to the vehicle's frame (if accessable). This requires care in avoiding warpage of the primary vehicle
structure . For popular conversions it is possible to obtain manufactured racks designed for a pre-
engineered layout, so this skill may be considered optional but dependent upon the vehicle selected for
conversion. For light truck conversions with in-bed batteries no welding is necessary - all retention
may be done with appropriate bolted hardwood components.

Automotive mechanics

The ability to remove, disassemble, rebuild, and install major ICE components such as transmissions,
engines, and suspension components is useful but may be performed by a specialty conversion shop.
The builder–owner should be especially cautious in the employment of ICE auto mechanics for these
tasks as they may be unfamiliar with specialized EV procedures and requirements.

Basic electrical

A builder should be sufficiently knowledgeable about basic electricity to safely work on household
and EV electrical systems. Note that an EV pack can provide extremely high currents, which can
rapidly heat wires or misused tools, causing burns, and that batteries so overloaded can explode with
consequent hazards of acid and toxic materials. Most traction packs and the associated high voltage
accessory wiring (heater and twelve volt converter) supply or use potentially lethal voltages. Specific
electrical arrangements are used to minimize the hazards present and it is important that the
builder/operator observe proper precautions and maintain the equipment in a safe configuration.

Basic electronics

While the systems used in EV safety are not exotic, the builder should have sufficient skill to design
and implement basic relay and diode logic for control and alarms. The smaller relays needed may be
obtained at a local electronics supply shop or through an EV parts supplier. Some specialty
components are obtained from EV parts suppliers or sometimes from automotive parts recyclers.




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                                 Gas2Electric - Electric Car Conversion Guide



                                                       Why Drive an
                                                    Electric Vehicle?

The greatest fans of electric vehicles are those who have obtained and used them. Owing to the fact
that electric vehicles have not been promoted by the major manufacturers in the United States, this is a
self-selected group, so their enthusiasm may be misleading. Fans point out the following:

   •   Range is adequate if not the only vehicle in household or if long commutes are not required.
       Fans point out that most trips in non-commute vehicles are for shopping, school drop-off/pick-
       up, visiting, and other errands within a 10 to 20 mile (15 to 30 km) radius. Long range is simply
       not needed for such trips and an operating range of 30 to 40 miles (50 to 65 km) is quite
       sufficient.

   •   Fueling at home requires but seconds to plug in for overnight charging followed by a few extra
       moments in the morning. Some find this to be more convenient than driving to obtain gasoline
       whose availability and cost is less predictable.

   •   The homeowner can install on-grid solar photovoltaic rooftop power or residential wind
       generation and so produce most of the energy required for personal transportation with zero
       pollution. Since the vehicles can be charged during low demand times the photovoltaics provide
       a larger societal benefit by helping to satisfy local peak demand, greatly reducing overall
       pollution and reducing transmission line loads. Additional benefits can also flow to the user
       through time sensitive pricing/payback schemes, significantly reducing the cost of a system that
       will support transportation needs. Once a commitment to producing power is made it becomes
       an easy decision to commit to producing all household and local transportation power needs.
       Thus there is a societal benefit from electric vehicles beyond transportation.

   •   Electric vehicles are quiet. Even if not completely silent, they do not produce the low frequency
       rumble that can easily penetrate household walls and windows.

   •   Owners take pride in the non-polluting nature of their vehicles. Some point out that knowing
       that your vehicle is non-polluting quickly leads to a realization how stinky and noxious even




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                               Gas2Electric - Electric Car Conversion Guide
    modern, well tuned non-electric vehicles actually are — something that tends to be ignored
    when you are part of the problem.

•   Some EV fans with a left of center political bias or of a "green" inclination claim that when
    combined with household photovoltaics, electric vehicle users are not assisting (through their
    fuel purchases) despotic governments in oil-rich countries, nor the politically powerful
    companies that prepare and distribute their products, nor the politically powerful coal interests,
    nor the domestic politicians that serve and protect these companies and countries. Many electric
    vehicle owners and operators express great satisfaction in this aspect of electric vehicle use,
    even while acknowledging that this use can have only little effect on these matters unless
    adopted more widely and produced in greater quantities.

•   Some EV fans with a right of center political bias believe that EVs will free the country from
    foreign sources of energy to ones domestically produced. This can make a country less
    strategically dependent on non-democratic oil-rich countries like Saudi Arabia.

•   Some USA EV fans have accused the three major domestic manufacturers, General Motors,
    Chrysler Corporation and Ford Motor Company of deliberately sabotaging their own electric
    vehicle efforts through several methods: failing to market, failing to produce appropriate
    vehicles, failing to satisfy demand, and using lease-only programs with prohibitions against end
    of lease purchase. They also point to the Chrysler "golf cart" program as an insult to the
    marketplace and to mandates, accusing Chrysler of intentionally failing to produce a vehicle
    usable in mixed traffic conditions. The manufacturers, in their own defense, have responded
    that they only make what the public wants. Of the various electric vehicles marketed by the
    "Big Three", only the General Motors EV1 (manufactured by GM) and the Th!nk City
    (imported and marketed by Ford) came close to being appropriate configurations for a mass
    market. However, at the end of their programs GM destroyed its fleet, to avoid the continuing
    expense necessary to continue to provide maintenance and support for these vehicles. Ford's
    Norwegian-built "Th!nk" fleet was covered by a three-year exemption to the standard U.S.
    Motor Vehicle Safety laws, after which time Ford had planned to dismantle and recycle its fleet;
    the company was, however, persuaded by the Norwegian Government and others to not destroy
    its fleet but return them to Norway and sell them as used vehicles. Ford also sold a few lead-
    acid battery Ranger EVs and has allowed a small percentage of lease returns into a limited
    market (after crushing and destroying 90 percent of the fleet, without saving any components),
    and some fleet purchase Chevrolet S-10 EV pickups are being refurbished and sold on the
    secondary market.




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                                                    Type of Car used
                                                      In Conversion

Family Commuter - vehicles that are lightweight and compact are generally best for this type of
electric vehicle. Cars such as a sedan can accommodate 16-20 6 volt batteries have a range of about 40
miles. 6 volt batteries have a greater energy density which is a necessary component for range.

Utility Vehicles – pick-up trucks are most preferred for utility purposes. 20 6 volt batteries are most
common although, for extra range 4 more 6 volt batteries can be used, increasing the volts to 144.

High Performance – for high performance vehicles, it is best to use the lightest car possible with a
structure that can handle the weight of the batteries. The most popular type of battery are 144 volt
systems or more using 12 volt deep cycle batteries such as Optima yellow tops or Genesis Hawker
batteries.




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                                                                 Tips for Your
                                                                  Conversion

- Manual transmission is best to use when converting to an electric vehicle. Using an automatic draws
more amps and shifting may take place at the wrong RPM times and the range will be much less.
Electric vehicles do not idle, so they do not pose the problem of stalling.

- Power breaks are recommended because it adds weight to the batteries.

- Power steering can be used, but is not necessary to add to a simple conversion. However, an extra
motor would be needed.

- Air conditioning is not necessary for an electric conversion because it places a greater strain on the
batteries.

- The car chosen to convert should be free of any rust. Generally, rust on the outside indicates a worse
problem on the inside.

- Conversions can add between 200 and 500 pounds to the vehicle, so it is important to check the
weight of the car and make sure it is still within reason after the conversion.

- All the cars should be converted with manual transmission. It isn't feasible to convert an automatic
because you will have more amps drawn and the shifting will take place at the wrong RPMs times
with the electric motor. Your range will also be much less because of this. With a standard
transmission you can control your amps consumption with your shifting and the right times when to
shift.

- During your conversion you should use a clutchless vehicle. It is much more practical to build a
clutchless design for an electric vehicle. The motor doesn't have an inertia mass when spinning that
has to be countered when shifting as does a normal combustion engine. An electric motor winds down
quite quickly so you can shift as a normal clutch vehicle.




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                                                                               Guide to
                                                                               Batteries

The most popular battery that is used and easily available to those doing their on electric vehicle
conversion is the deep cycle lead acid battery. They are then further divided into flooded batteries and
sealed batteries.

Flooded batteries are inexpensive, durable and have a high energy density. However, they are heavy
and are not a good choice when converting high performance vehicles.

Sealed batteries do not weigh as much as flooded batteries, have low resistance and can be installed in
various positions. Although, this type of battery is more expensive, have a less range and does not last
as long.


Battery technologies

The following is what you want to look for when you decide to purchase batteries for your EV

   •   Life cycle cost
   •   Initial cost range
   •   Energy density (The amount of energy stored in the least amount of space.)
   •   Peak power capacity
   •   Internal resistance
   •   Voltage depression
   •   Maintenance
   •   Available form factors
   •   Expected degree of discharge
   •   Low temperature operation

Lead acid

Lead acid cells are sensitive to "break in", in that severe use early in life can shorten the lifespan. They
are also sensitive to temperature, with low temperatures severely reducing the amount of energy



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available - sometimes battery heaters and insulated boxes are appropriate use in cold climates. If
sufficiently discharged the electrolyte can freeze at extremely cold temperatures, which can break the
case from expansion.

It is important that lead acid cells be kept charged. A deep discharge without an immediate recharge
can significantly reduce the capacity of the batteries. Lead acid batteries also give the most total
energy throughput over their useful life if the discharge cycles are relatively shallow, but such
repeated shallow discharging can reduce the total energy available between recharges. The electrolyte
is sulfuric acid in water and is not especially strong but is hazardous to skin, eyes, and clothing and
corrosive to steel and aluminum. It does not affect most plastics and stainless steel. It is easily
neutralized with common baking soda (sodium bicarbonate), which should be kept available near the
batteries. (Note that a common "dry powder" fire extinguisher is charged with sodium bicarbonate and
is appropriate for use on electrical equipment.) When combined with the acid it will evolve carbon
dioxide, leaving a relatively harmless sodium sulfate residue. When working on the batteries some
baking soda should be kept at hand in case of an electrolyte spill. Safety glasses should be worn when
working near or upon the batteries. Sometimes acid will leak from the seal between the top and the
case, or may be spilled when moving or testing the batteries. Such an acid leak can not only corrode
the vehicle's structure, it can also cause a highA–resistance current leak, which can cause some types
of battery chargers to fail with a ground fault. In the case of an acid spill, battery cases and tops
should be wiped down with a solution of water and baking soda. This should be repeated until no
bubbles of carbon dioxide are seen.

Discharge and failure to recharge will cause sulphanation, a chemical change on the surface of the
plates that reduces capacity and increases internal resistance. Keeping the battery properly charged
and well watered (where appropriate) is the best care to ensure long service life. Overcharge of some
types of batteries can also be harmful.

If the battery is not likely to be used and quickly recharged it should be placed on a "float charge",
where the charger applies a voltage that will not cause overcharging (which is harmless to wet cells
but consumes the water in the electrolyte through electrolysis into hydrogen and oxygen and is
damaging to other lead–acid battery types).

Batteries in general, and lead acid in particular, will sustain a greater lifetime energy throughput if
only partially discharged, generally less than 50 percent being considered an economical design point.
As lead acid batteries in particular have a high weight for a given capacity, and this weight must be
hauled by the vehicle, it becomes uneconomical in energy to have much excess capacity, but since the
greatest expense is not energy cost but rather battery replacement, the main effect of having too much
battery weight will be in its effect upon acceleration performance and brake wear.




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Flooded lead–acid

Batteries suitable for EV conversions are typically sold as "golf cart" batteries and offer the lowest
initial cost per watt-hour of capacity, high watt–hour capacity and reasonable life when properly cared
for. A typical configuration is a six volt battery containing three cells. They are also available in 4-
cell, eight volt configurations but these are rarely used in EV conversions owing to a higher total life
cycle cost. Flooded lead–acid batteries are conditioned periodically by overcharging to equalize the
state of charge of individual cells in the pack. Care must be taken when charging batteries indoors due
to the creation of potentially explosive hydrogen gas. If such cells are charged in an enclosed space
the charging station (or other switched outlet) should also be connected to a vent fan of appropriate
size and location. Being "wet" cells they require maintenance in the form of addition of distilled water,
or the addition of a Hydrocap™ - a catalytic device that recombines evolved hydrogen and oxygen,
reforming the water that would otherwise have to be replaced. When these caps are used the
temperature may be monitored to good effect; when all cells are fully charged, all of the caps will be
warm from the exothermic recombination of hydrogen and oxygen to water. Devices can be purchased
that allow fast and easy central-point watering of the batteries, if catalytic recombiners are not used.

Wet lead–acid cells will also shed material from their plates, which accumulates at the bottom of the
cell. Cells intended for long service life and deep discharge have extra space to accumulate these
materials. When the accumulation reaches the plates it will cause a (non-catastrophic) short circuit,
eventually rendering the individual cell useless.

This type of cell is particularly resistant to overcharging, since the dissociated water vented as gas
may be replaced, or recovered using a catalytic cap. This type is less resistant to vibration than other
types and the entire pack will become useless if the electrolyte in a single cell is lost due to case
damage, which by not allowing currrent to flow throught the cell will bring the entire vehicle to a halt.

The flooded lead acid cells used in EV conversions are readily available at low cost compared to other
batteries owing to their high volume use in other vehicles such as golf carts. These batteries tend to
have high weight in proportion to their peak capacity and a higher internal resistance than other lead-
acid types. Owing to the lower voltage in a battery unit (three cells with a nominal six volts) it is not
practical to build a high voltage light weight battery pack. Thus the advantages of the wet lead-acid
cell are best exploited in a light truck conversion and in lower voltage automotive applications (96
volts or less using six volt batteries, or 120 volts using eight volt batteries) in lighter vehicles. Note
that for certain battery voltages and sizes (e.g. the six volt Trojan T-105) the actual purchase cost can
be significantly lower that for other related batteries (e.g, the 16% heavier Trojan T-145), due to the
highly competitive golf cart market.




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Terminal melt-down

Batteries using tapered post connections are generally considered better than batteries with other
connection arrangements such as vertical stud, owing to the greater contact area and less tendency to
loosen in service as a consequence of plastic flow of the lead. The more expensive cable to post
connections will add to the total cost, however. If the stud type is used a small amount anti-seize paste
(typically used on exhaust manifold bolts) consisting of aluminum flakes in a grease carrier, should be
applied to only the stud threads before assembling the connection, keeping the electrical contact area
clean.

Batteries intended for automobile starting are not suitable for use in EVs as they are optimized for a
different charge-discharge profile and their short service life in this application will greatly reduce
their cost effectiveness.

Wet lead acid cells offer a high ampere-hour capacity compared to other types, 225A·h being common
in golf cart types. The 225A·h refers to a twenty hour discharge rate and the actual energy available
under typical electric vehicle conditions will greatly reduce the total energy available from this type.

Periodically the battery pack should be given a balancing charge. For such a charge the charging
voltage is increased to a value that will cause fully charged cells to electrolyze the water in the
electrolyte. Any cells not fully charged will continue to charge. Note that this can only be done with
the wet cell type as this procedure will damage or destroy other battery types.

A well cared for flooded cell pack in normal light truck service is generally expected to last about
three years. It may be possible to extend this life through electrolyte treatments, an option not
available with other lead–acid battery types. Buildup of shed plate material below the cell will limit
the ultimate life of the battery.

The few major brands available for this type of battery use different connection locations and so the
vehicle may require new cables if the type of batteries installed are significantly changed. Many house
brands of batteries will use one of the few major manufacture's form factors.




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Absorbed glass mat (AGM) lead acid




The ability to position AGM batteries at odd angles is a distinct advantage in this conversion of an
elderly Fiat

Compared to wet lead acid these cost far more, have shorter life, far less ampere–hour capacity, but
much more maximum power output per unit weight, greater durability, and lower maintenance
requirements. Owing to their high output and lower weight per cell this type is particularly suitable for
high performance vehicles, being commonly used in electric drag racers and low cost sports cars.
Some configurations have been optimized for light weight electric vehicles, offering 12 volts from six
cells in a 45 pound (20 kg) package, but only 55 A·h at a slow discharge rate. This type of cell offers
low internal resistance and so batteries made from these cells can deliver high power outputs for their
size and weight. While substantially more expensive both per ampere-hour and in lifetime energy
throughput than wet lead-acid cells they are still considerably less expensive than other types of
batteries.

This type is suitable as a replacement for wet cells but must be carefully protected from overcharging
as there is no means for replacing lost electrolyte water due to outgassing. The ability to mount these
batteries at an angle may be an advantage in some smaller vehicles. The leading developer of this type
of battery, Optima, was purchased by Johnson Controls and folded into their Interstate battery group.
Subsequent problems with new dead batteries (palette load shipments) have been reported on some
electric vehicle forums.

Lead acid gel-cell

Gel cells are sealed and the electrolyte is non-liquid. This requires that they be operated and charged
within carefully controlled ranges to avoid overcharging. They are also unsuitable for the high-current
requirements of a typical direct current application. They are suitable for low current high voltage
applications such as is typical in an alternating current system. Gel cells are commonly used in electric
bicycles and scooters, and in computer uninterruptible power supplies. This type of cell has been used
in CalCars' plug-in hybrid conversion of a Toyota Prius, but is intended only as proof of concept for
that application owing to its weight compared to other technologies. While infrequently used in EV



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conversions this type of cell is available in a wide variety of battery shapes and sizes and this is
advantageous if battery space is limited. As many of these batteries have limited total power and
current capacity they are sometimes used in parallel groups (called "buddy batteries") to construct a
pack. This type is more sensitive to damage by incorrect charging profiles than is the AGM type. As
the gel immobilizes the electrolyte it is not subject to stratification as is the wet cell type. The gel
makes overcharging particularly destructive to this type of battery since any evolved gas bubbles
(hydrogen or oxygen) will remain at the surface of the respective plate and so prevent electrolyte
contact and hence can severely reduce the storage capacity of the battery. Gel-cells are used in the
Solectra Force, a commercial conversion of the Geo Metro that is no longer in production.

Valve regulated lead acid (VRLA)

A version of this battery by Panasonic was used in General Motrors' ErV1 electric vehicle, and a
version by Delphi in Ford Motor Company's Ranger EV. As with most other batteries, careful
charging patterns are required to avoid overheating or loss of electrolyte. VRLA batteries contain
catalytic materials to recombine evolved hydrogen and oxygen back into water before they escape to
the atmosphere.

Foam plate and anti-sulphination coatings

A recent development the carbon foam grid was initially developed by
[w:en:Caterpillar_Inc.|Caterpillar Inc.]] in an attempt to create a more robust battery for use in grading
and construction equipment. Such equipment is often inactive during a portion of the year and is
subject to strong vibrations when in use. This environment will require the frequent replacement of
lead-acid service batteries. Carbon foam was being investigated by Caterpiller [for use in radiators
when it was noticed by an in-house battery investigator and subsequently applied for use in the
cathode and anode plates of flooded lead acid wet cells. The carbon foam has a very good resistance to
repeated bending (a high fatigue life) and a very large surface area, both beneficial to Caterpiller's
battery applications. A spinoff company, Firefly Energy was created for the commercial development
of this technology. The first commercial product of this effort, a Group 31 truck battery, is expected in
2008, will be sold under the Oasis brand. As trucks are needing considerable energy for "hotel" loads
to operate sleeper cabs when the truck is not in use the application is more akin to that of a deep-cycle
marine battery rather than that of a simple vehicle starting load. The expectations are that this new
battery have better than 40 percent additional capacity and will allow up to 800 full recharge cycles
compared to the typical 200 cycles for a conventional Type 31 truck starter battery, and this while
replacing only the negative plate with carbon foam. A more advanced application will replace also the
positive plate, with projections that at least a third of the weight may be eliminated for the same
storage capacity. Special coatings have also been developed by Firefly that reduce the sulfination
effects of long discharged times. It is unlikely that batteries specifically suitable for electric vehicles
will be available before 2010, and the current Group 31 battery will initially be available only for fleet




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use. Given the expected performance and cost parameters of this technology there is considerable
interest in these developments within the EV conversion community.

Nickel cadmium (NiCd or "Nicad")

The nickel cadmium cells suitable for EV use are "wet" or "flooded" cells. The cadmium in a nicad is
particularly toxic, far more so than lead. The battery does not use an acid electrolyte but rather a base,
sodium hydroxide also known commonly as lye, used in processing food, making soap from fat,
cleaning drains and many other applications. The electrolyte is hazardous to the eyes and can burn
skin but is easily neutralized with common vinegar, which should be kept available when performing
battery maintenance. Unlike acids, bases do not attack steel but are extremely corrosive to aluminum.

For long term use the higher cost may be well repaid owing to longer life. NiCads will typically have
about 50% more energy for the same weight than lead-acid, and can be safely discharged to very low
levels. Most wet Nicads also are said to lack "punch", not having the ability to supply high currents
seen from AGM lead-acid cells.

Nicads also exhibit "memory", requiring periodic deep discharge (usually a series of three full
discharge-recharge cycles) in order to regain battery capacity

This type of battery was applied commercially in the Th!nk City EV.

Nickel metal hydride (NiMH)

These have been used in some production vehicles such as some versions of the Chrysler TEVan, Ford
Ranger EV, GM EV1, Honda EV Plus, and the Toyota RAV4 EV. They are also used in most hybrid
vehicles, Their use in hybrid vehicles may result in substantial reduction in cost over the next few
years (written 2005). As is well known by cell phone and some digital camera users these batteries
have a high self-discharge rate.

Lithium-ion (LiIon)

These offer the highest energy density commonly available, although at substantial expense. They
were used in the Nissan Altra electric vehicle. They are currently not cost effective for most
converters but the technology is developing rapidly and this type is being used in portable power tools.
Previously available versions of this type of battery would degrade over time even if not frequently
cycled - exhibiting a" calendar life". Improvements are expected in the near future as indicated by the
recent development of enhanced versions of this type specifically for application in hybrid vehicles by
Panasonic. This type will be used in a third party conversion of the Prius hybrid to create a plug-in
hybrid, expected to be available in 2006.




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A new development in lithium-ion technology may be promising to EV conversion. A123Systems
claims their new battery technology delivers up to 10X longer life, 5X power gains and five minute
recharge. This new product also boasts a significant cost and weight savings vs. NiMH or
conventional Li-Ion technology. The price seems comparable to high end lead acid batteries with
developer kits available. Homebuilders should be cautious of new technologies however until the
product is in the marketplace for some time. Dewalt will be offering this technology beginning in
2006 so this should give real world testing of this battery

The Tesla Roadster will be powered by LiIon, with a range over 200 miles, 0-60mph in 3.9 seconds,
and top speed of 130mph.

Nanotechnology batteries

Pack sizing

Several considerations apply to selecting pack capacity, particularly when lead-acid cells are used.
Lead-acid cells tend to degrade in capacity in a predictable manner. If the pack is undersized for the
application it may perform satisfactory for a time, but due to loss of capacity may not provide
sufficient range for its intended use, even though the batteries have substantial useful life remaining.
Excess initial capacity will thus increase the service life of the pack. On the other hand, larger packs
are not only more expensive, but have to be hauled, so excess capacity will both reduce economy of
operation, acceleration and increase brake wear.

Pack voltage

If you plan on converting a lightweight vehicle not suitable for freeway you will want to keep in mind
that they will typically use 24, 36, 48, or 72 volt battery packs.

If you choose to drive over freeways you will want to use DC propulsion. DC propulsion systems in
EV conversions intended for freeway use will usually be 96, 108, 120, 144, or 192 volts. AC systems
will usually be 192 volts or higher.

96 volt and 108

Using wet cell golf cart batteries

96 volts, obtained using sing sixteen 6 volt wet cells* (used in electric golf carts) and a nine inch DC
motor in a light truck this will give sufficient performance for around town and for limited (but not
hasty) freeway driving. The total pack battery, holddown, and cabling weight will be about 16×65 lb =
1040 lb (470 kg), representing a substantial reduction in the vehicle's useful load carrying capacity.
The nominal watt-hour capacity will be 225×96 = 21.6 kW·h, with a practical yield considerably less
than this value. Nominal specific capacity is 20.8 W·h/lb (45.8 W·h/kg). With sufficiently high




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(120VAC mains) it may be possible to use a simple non-isolated charger to charge 18 batteries for 108
volts nominal. An 18 cell pack using Trojan T-145 or equivalent will offer over 140 percent of the
system capacity of 16 T-105 or equivalent, for a substantial increase in range with about 130 percent
of the weight. The higher capacity batteries will be less cost effective (by a factor of about .92), due
mostly to the larger volume demand for the popular T-105 type.

   •   Calculations based upon Trojan-T-105 with two pounds allowance for cable and hold-down.

Using AGM batteries

With a light vehicle and eight 12 volt AGM batteries the performance should be substantially
improved and quite suitable for short range use. Note that AGM batteries have a substantially higher
peak current capacity and lower internal resistance than wet cells. The total pack battery, hold down
and cabling weight will be about 8×46 = 368 lb (167 kg). This lower weight is much more suited to a
lightweight vehicle than are the wet cells described above.

   •   Calculations based upon Optima D34/78-950 (yellow top) with two pounds allowance for cable
       and hold-down. Use of blue tops would result in a pack weight of about 8×62 = 496 lb (225 kg).

120 and 128 volts

These are configured using twenty 6-volt, ten 12-volt, or fifteen 8-volt (wet cell golf cart) batteries.
These configurations were rare since other equipment (the pack to 12-volt converter) was not easily
available in these input voltages, a problem now solved by some vendors. 120 volts is especially
attractive since a pack may be constructed with twenty six-volt batteries. As suitable wet cell traction
batteries in quantity are packaged as pallet loads of 40, two vehicle owners may purchase and divide a
pallet with no leftovers. Since common controllers will typically operate between 96 and 144 volts the
controller is not operating at the upper limit of its voltage range.

144 volt

Under similar circumstances this should enable a DC conversion to operate with the acceleration
normally obtained from the ICE original. If the same battery types are used one could expect about 40
percent additional range compared to a 96 volt system. Note that if six volt wet cells are used the
additional eight batteries will weigh an additional 560 pounds (250 kg), representing a substantial
decrease in load carrying capacity and in economy of operation. If more advanced battery
technologies are used then the performance penalties are substantially less.

Using the popular Trojan T-105 battery a pack of 24 batteries (exclusive of cabling and tie-downs)
would weigh 1392 lb (672 kg).




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                                  Gas2Electric - Electric Car Conversion Guide
Where this voltage is desired in a somewhat lighter and more compact wet cell pack it may be
constructed using eighteen 8 volt batteries. Using the Trojan T-860 a pack would weigh 1008 lb (600
kg). As the T-105 and T-860 batteries are the same size, the total volume required by the T-860 would
use considerably less volume, 75% of a pack built with the T-105 (but would have only 66% of the 5
hour rate ampere-hour capacity. The nominal capacity will be 21.6 kW·h, so this pack will have the
same overall capacity as that of a 96 volt pack using 6 volt T-105s, but will require two more battery
stations. The added voltage will give an improved performance, but if used often that extra
performance will have less range. As there is far less demand for eight volt batteries as compared to
the common six volt golf cart battery, the cost per watt-hour stored will probably also be higher.

144 volts is also a common upper limit for voltage applied to certain commonly available mid-priced
controllers such as some models of the widely used Curtis. Owing to the current limitations of that
controller the main effects compared to lower voltage systems will be to increase the range and to
ensure effective performance at deep discharge levels. Effective exploitation of the higher voltage to
obtain increased acceleration requires the use of a specialized high-current controller, such as the
Zilla.

192 volt

This is becoming the conversion industry standard for high performance street vehicles such as sports
car conversions. This voltage is not typically used with large wet cells owning to the high weight of
the total battery pack (32×70 = 2240 lb, about 1000 kg), Instead usually either AGM lead acid (740
pounds or 340 kg for Optima Yellow Top) or wet cell NiCads (908 lb or 410 kg for SAFT STM).

Higher voltages

Higher voltages are used in specialized vehicles such as drag racers and for some AC motor
conversions. Since high voltage systems use substantially less current it is possible to use gel-cell lead
acid, unsuitable for higher current applications as they are subject to permanent damage at high
current flows.




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                                 Gas2Electric - Electric Car Conversion Guide




                                                             Tools Needed

Converting your car requires the following tools. Please make sure you have them on hand before you
begin your conversion.

             Jackstands                             Hammer

             Floor jack                             Punches

             Wheel chocks                           Chisels

             Engine hoist                           Hack saw

             Saw horses                             Screwdrivers

             Workbench or                           Socket wrenches
             Workmate

             C-clamps                               Torque wrench

             Drop light                             Wrenches

             Soldering iron                         Pliars

             Combination wire                       Aviation snips
             stripper and
             crimping tool
             Cable shears for
             2/0 welding cable


             Lug crimpers for 2/0                   Drill and/or drill press



                                        Page 19 of 41
                    Gas2Electric - Electric Car Conversion Guide
welding cable

Heat gun for heat                Circular saw
shrinking tubing

Saber saw                        Grinder

Measuring tape                   Square

Level                            Volt meter




                         Page 20 of 41
                            Gas2Electric - Electric Car Conversion Guide



                                              Supplies For The
                                                  Conversion

- 1" x 1" x 3/16" angle iron, 12' length for battery rack
- 1" x 1" x 3/16" angle iron, 5' length for battery rack
- 1 1/2" x 1 1/2" x 3/16" angle iron, 20' length for battery rack
- 3/4" x 3/4" x 1/8" angle iron, 20' length for battery hold down
- 1" x 1" x 1/8" metal, 10' length for various brackets
- 4' x 8' x 3/4" plywood for battery box
- 4' x 8' x 1/2" polyurethane foam insulation for battery box
- 1 1/2" x 20' PVC pipe for conduit
- 5" x 10' vent hose for battery box ventillation
- 1/4" Fomecore for models and templates
- Elmers wood glue
- 4 cans Black Rustoleum spray paint for engine compartment and brackets
- 2 quart Rustoleum primer for battery box
- 2 quarts White Rustoleum Waterproof paint for battery box
- Noalux: compound applied to battery lugs to prevent corrosion
- Stainless steel bolts, nuts, washers and lockwashers for brackets and hardware
- Grade 8 automotive bolts, nuts, washers and lockwashers for motor mounts
- battery racks




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                                   Gas2Electric - Electric Car Conversion Guide




                                                                Parts Needed

                      Advanced DC Motor
                      The motor is an 8" Advanced DC
                      series-wound motor. It weighs 107
pounds and is rated at 68 peak
horsepower. These motors are
available in several sizes.


                    Adaptor plate
                    The adaptor plate mates the motor to
                    the transmission. It is constructed of
                    1/2 inch aluminum and is pre-drilled
                    with bolt hole patterns for both the
                    motor and transmission. An
                    aluminum spacer is also used for
proper spacing between the shafts of
the transmission and motor. Adaptor
plates are available for many cars.



                      DC Motor Controller
                      The controller regulates current
                      going to the motor. It is a solid-state
                      device that uses a pulse width
                      modulator (PWM) that sends short
bursts of current to the motor at a
rate of 15 kHz. Controllers are
available from both Curtis and DCP.



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                                  Gas2Electric - Electric Car Conversion Guide



                   Potbox (Potentiometer)
                   The potbox is a 5K ohm throttle
                   between the controller and the
                   accelerator, similar to the way a
sewing machine pedal works. The
potbox's lever arm is attached to the
existing accelerator cable.




                     Main Contactor
                     An electric relay that serves the
                     same purpose as the ignition switch
                     in a gas car. When the key is turned
to the start position, the contactor
closes the circuit to allow current to
flow to the controller.




                    Circuit Breaker
                    A safety device that shuts down
                    power for servicing or during an
                    emergency. The circuit breaker is
                    installed under the hood and can be
switched both off and on from the
drivers seat with an extension or
cable.



                    Main Fuse
                    The main fuse protect the system
                    from high voltage spikes. A fuse
should be installed at each battery



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                                  Gas2Electric - Electric Car Conversion Guide
box or group of batteries.



                        Shunt
                        A shunt is placed in series within the
                        wiring as a means to connect
                        meters. Shunts are available in
different sizes for both high and low
power configurations.



Charger interlock
A relay that keeps the circuit open so
nobody will inadvertantly drive off
with the charge cord plugged into the
car.


                    DC/DC Converter
                    The DC/DC converter is similar in
                    function to a gas car's alternator. It
                    charges the 12 volt accessory
battery by chopping voltage from the
main battery pack down to 13.5
volts.




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                             Gas2Electric - Electric Car Conversion Guide



                                                               Precautions
                                                                   to Take

- Always shut off the power when servicing the car.
- Dissipate the capacitors from the controller before servicing the controller or propulsion system.
  Even though the controller is off the capacitors may still be live. A light bulb works well as a
  dissipation device.
- When servicing the drive train always keep the drive wheels off the ground with proper jack
  stands.
- Keep loose hair, jewelry or clothing away from spinning motor shafts.
- Always wear proper eye protection when working with power tools and handling batteries.
  Deep-cycle batteries contain caustic acid which may splash or spill when they are moved or
  handled.
- Wear protective clothing when carrying or moving batteries. Acid could spill and burn a hole
  through any clothing it contacts.
- Wear steel toed boots when carrying or moving batteries. Batteries can weigh up to 80 pounds
  and can cause serious injury if they fall.
- Wear heavy gloves when moving or carrying batteries. Use protective rubber or latex gloves
  when checking or watering batteries.
- Always provide proper ventilation when charging batteries. A small spark can cause a fire if
  hydrogen gas accumulates in an enclosed area.
- Never inhale the fumes when watering the batteries.
- Tape the ends of wrenches when tightening battery terminals. A loose wrench can come in
  contact with battery terminals and cause a short.
- Never ground the propulsion batteries.
- Never work on the car when you are tired or in a hurry.




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                                 Gas2Electric - Electric Car Conversion Guide



                                                             Beginning the
                                                               Conversion
The first step in the conversion of an electric vehicle is to remove all of the gas parts such as the
engine, radiator, gas tank, fuel lines, exhaust system, emission wires and hoses. Other parts like the
flywheel, transmission and clutch can be held onto for use in the conversion.

Measurements are important to keep track of. At the end of the conversion, the original measurements
will be needed to know if the suspension will need more work. The ride height at the top of each
fenderwell will also need to be recorded. Measurements of the transmission need to be taken in order
to ensure proper alignment once the electric motor has been installed.

Labeling all wires is also important when beginning the conversion. Ignition wires need to be located
because the electric car is turned on using the existing ignition switch.

Once the engine compartment is degreased and painted, the electric parts can be installed and it is at
this point that the actual conversion begins.




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                                 Gas2Electric - Electric Car Conversion Guide




                                                                            Installing
                                                                           the Motor
Using an aluminum adapter plate and spacer ring, the motor can be mounted to the transmission.
Usually, the adaptor plate is made of ½ inch thick adonized aluminum and is available for a wide
variety of cars. The spacer ring ensures correct clearance between
the motor shaft and the transmission shaft. The hub, which is attached to the motor
shaft, is used to mate the flywheel to the electric motor and the clutch assembly bolts
to the flywheel just as it did on the gas engine.

The first step of the motor assembly is attaching the hub to the motor. The hub given in the kit is
machined with a key way, two threaded holes for the set screws and a matching bolt pattern for the
flywheel. Once the hub is on the shaft, drill into the shaft through the set screw holes so the screws
will seat properly. Blow out any metal shavings and screw the set screws in place. Two set screws are
used for each hole, one on top of the other.

When positioning the motor, the terminals should be easily accessible once it is mounted in the car.
The spacer plate and adapter plate should be positioned to the face of the motor and then bolted into
place. Bolt the flywheel to the hub and then the clutch assembly to the flywheel. Check to make sure
all bolts are tight and positioned correctly.

After assembly of the motor, it is lowered into the engine bay and bolted to the transmission. Make
sure the shafts of both the motor and the transmission are aligned. Afterwards, test that the motor shaft
is also rotating by putting the car into gear and rotating the tire while the drive wheels are off the
ground. Then the motor can be hooked up to a 12 volt battery and the gears briefly run through to
make sure all is well balanced.

The motor then needs to be bolted to the frame of the car. Since one end is already secured to the
transmission, only one end needs to be bolted. The conversion kit includes a motor support that wraps
around the motor and has a base that allows a bracket to be mounted to the car. Although a few
different options are available, the most common way to attach the motor is by attaching the brace
from the upper motor mount attachment points on the car to the motor support.




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                                  Gas2Electric - Electric Car Conversion Guide
For rear wheel drive cars, the motor support can be attached to a brace that attaches to both frame
rails. Attaching to this particular car may require addition of a torque bar from the frame of the car to
the motor in order to prevent the motor from twisting in the support when the car is started.




                                          Page 28 of 41
                                 Gas2Electric - Electric Car Conversion Guide



                                                                Installing the
                                                                Components

Installing the components is one of the easiest tasks in an electric conversion because they require
very few parts. The parts need to be placed in exact spots in order for them to work properly. Ideally,
the parts should be placed close together in order to keep the length of the wires short.




The controller needs to be placed so it can get the cooling it needs to work properly such as in an
airstream or on top of a heatsink. The potbox should be on a sturdy surface and the accelerator cable
should be placed in a way which prevents kinks or pinching. When the contactor closes, it sparks
slightly and should be placed under the top of the batteries. Air bags are sometimes installed to
support the weight of the rear batteries.




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                                  Gas2Electric - Electric Car Conversion Guide



                                                                  Installing the
                                                                   Battery Box

Batteries need to be stored in a protective box, as generally ten of them will be placed in the in back of
the passenger compartment. The box prevents fumes from entering the car when the batteries are
charging as well as keeps them warm during the cold weather.

An explosion proof, brushless fan is attached on the side of the box so the batteries can be ventilated
while charging. It is wired in such a way so the charger and the fan can be on simultaneously.

The box should be constructed out of marine grade plywood and painted with water repellant paint.
Metal is used so the weight of the batteries does not break the box. It is installed to the frame of the
car; depending on the car, it may also fit in the trunk.




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                                 Gas2Electric - Electric Car Conversion Guide



                                                        Wiring up Your
                                                        Electric Vehicle

There are four basic wiring systems in the electric vehicle,

Propulsion – high voltage to power the electric motor (96 volts), battery pack is split between the front
and back of the car.

12 Volt – powers accessories such as the radio and lights.

Charging system – uses 120 VAC household current to charge the batteries. Has a built in ammeter so
amperage can be adjusted according to the available current.

Driver’s displays and controls – work pretty much the same way as in a gas car.

Other components which need to be wired in the electric vehicle is the charger interlock. This works
as a safety relay which opens the contactor which prevents the car from driving itself when the
batteries are charging.

Please use the following image to assist you in visualizing the wiring work.




                                          Page 31 of 41
Gas2Electric - Electric Car Conversion Guide




     Page 32 of 41
                                  Gas2Electric - Electric Car Conversion Guide



                                                             Driving Your
                                                          Electric Vehicle

Before actually taking the car on the road, the batteries should be fully charged and the battery charger
tested one more time. All the wiring systems should be inspected again and the air shocks should be
filled.

Finally, it is time to turn the key into the stating position. Instead of hearing the normal start-up of a
gas car, you should hear the click of the contactor and then silence. Put the car into gear, press the
accelerator and enjoy the ride.

The car will be very quiet and this will make it easy to hear any noises signaling a problem. You will
hear the vacuum pump turn on every now and then to maintain proper level of vacuum for the brakes.
The first ride may not have as long a range as expected; the batteries usually need about 40 charges
before they can perform at their optimum level.

Other than that, the car should break and accelerate with ease. The project may seem a little high in
price to begin, but in the long run, with gas prices being what they are, it will all be worth it. Enjoy the
ride in your brand new electric vehicle!




                                           Page 33 of 41
                                 Gas2Electric - Electric Car Conversion Guide




                                                                            Glossary

A
      Ampere
AGM
      Absorbed Glass Mat
Ah
     Amp-hour
Absorbed (or absorptive) Glass Mat
     A technique for sealed lead-acid batteries. The electrolyte is absorbed in a matrix of glass fibers,
     which holds the electrolyte next to the plate, and immobilizes it preventing spills. AGM
     batteries tend to have good power characteristics, low internal resistance, and good behavior
     during charging.
Amp, Ampere
     Unit of electrical current. Abbreviated "A"
Amp-hour
     Unit of electrical energy, one amp of current flowing for one hour. Abbreviated Ah
Anode
     The negative electrode of a battery (or other device).
Automotive post
     A battery terminal style found on starting batteries in internal-combustion vehicles. A round
     post made of lead. See terminal styles for comparison.

BCI
      Battery council international. Promoters of battery standards, notably the "Group sizes" which
      specify the external dimensions of a battery. See also the group size chart. BCI has a web page.

C20, C6, C1, etc




                                          Page 34 of 41
                                 Gas2Electric - Electric Car Conversion Guide
      An expression describing rate of discharge. The number indicates the number of hours to
      completely discharge the battery at a constant current. So C/20 is the current draw at which the
      battery will last for 20 hours, C/1 is the current at which the battery will last 1 hour. The useful
      capacity of a battery changes depending on the discharge rate, so battery capacities are stated
      with respect to a particular rate. For instance, a particular model of Hawker battery is rated at 42
      amp-hours at the C/10 rate of 4.2amps, but only 30 Ah at the C/1 rate of 30A. Also written as
      the 20-hour rate, 1-hour rate, etc.
CCA
      Cold Cranking Amps
Cathode
      The positive electrode of a battery (or other device).
Cold Cranking Amps
      A performance rating for automobile starting batteries. It is defined as the current that the
      battery can deliver for 30 seconds and maintain a terminal voltage greater than or equal to 1.20
      volts per cell, at 0degrees Fahrenheit (-18Celsius), when the battery is new and fully charged.
      Starting batteries may also be rated for Cranking Amps, which is the same thing but at a
      temperature of 32F (0C).
Cycle Life
      How many charge/discharge cycles the battery can endure before it loses its ability to hold a
      useful charge. Cycle life typically depends on the depth of discharge. For example, if a
      hypothetical battery pack will propel your car for a maximum range of 100 miles, and you drive
      50 miles between charges, (50% DOD) then you may get 600 trips before replacing the pack;
      but if you drove 80 miles between charges, you might only get 400 trips before the pack wears
      out. (All numbers were made up.)

DOD
     Depth of Discharge.
Depth of Discharge
     The amount of energy that has been removed from a battery (or battery pack). Usually
     expressed as a percentage of the total capacity of the battery. For example, 50% depth of
     discharge means that half of the energy in the battery has been used. 80% DOD means that
     eighty percent of the energy has been discharged, so the battery now holds only 20% of its full
     charge.

ECD
      Energy Conversion Devices
Electrode
      A conductor by which electrical current enters or leaves a non-metallic medium, such as the
      electrolyte in a battery (as well as vacuum tubes and lots of other devices).
Electrolyte




                                          Page 35 of 41
                                  Gas2Electric - Electric Car Conversion Guide
      An elctrically conductive medium, in which current flow is due to the movement of ions. In a
      lead-acid battery, the electrolyte is a solution of sulfuric acid. In other batteries, the electrolyte
      may be very different.
ElectroSource
      Makers of "Horizon" advanced lead-acid batteries. They have a web site.
Energy Conversion Devices
      Parent company of Ovonics.
Energy Density
      The amount of energy that can be contained in a specific quantity of the fuel source. Typically
      quoted in watt-hours per pound, wh/lb, or watt-hours per kilogram, wh/kg. For example,
      flooded lead-acid batteries generally have about 25 wh/kg, the latest advanced lead-acid designs
      claim about 50 wh/kg, and newer battery technologies such as NiMH and LiON are in the 80-
      135 wh/kg range.

Flooded cell
      A design for lead-acid batteries. The electrolyte is an ordinary liquid solution of acid. Flooded
      cells are prone to making gas while being charged. Flooded cells must be periodically checked
      for fluid level and water added as necessary. Flooded cells are also typically less expensive than
      AGM or gel type lead-acid batteries.
Fuel Cell
      A battery where reactants are supplied to the cell from an external source. The most commonly
      cited example is the hydrogen fuel cell, in which hydrogen and oxygen are combined,
      producing electric current and water.

GNB
     GNB Industrial Battery company, maker of lead-acid batteries.
Gel Cell
     A technique for sealed lead-acid batteries. The electrolyte solution is in a gel form, usually
     silica gel, instead of plain liquid.
Genesis
     Brand of advanced lead-acid battery made by Hawker Energy Products.
Group size
     A set of standard sizes for the external dimensions of a battery, standardized by BCI. All "group
     27", etc, batteries are the same size, though they may differ in weight and capacity. We have a
     chart of the group sizes most likely to be found in a car.

Hp
     Horsepower
Hawker
     Manufacturer of "Genesis" advanced lead-acid batteries. They have a web site.
Horizon



                                           Page 36 of 41
                                 Gas2Electric - Electric Car Conversion Guide
     Brand of advanced lead-acid batteries made by ElectroSource. (also apparently the name of a
     stationary power supply system made by Exide.) The plates in a Horizon battery are arranged
     horizontally, instead of the more common vertical arrangement, hence the name. Horizon
     batteries have very high energy density for lead-acid batteries, but are not general available at
     retail.
Horsepower
     Unit of rate of doing work. Defined as 550 foot-pounds per second. One horsepower is about
     746 watts. (A horsepower has also been defined as the amount of power needed to drag a dead
     horse 500 feet in 1 second, but this was not accepted by the international standards community.)
Hydrometer
     A tool for testing the specific-gravity of a fluid, such as the electrolyte in a flooded battery.
     Typically a squeeze-bulb is used to suck up a sample of the fluid, and a float indicates the
     specific gravity.
Hygrometer
     A tool for measuring the humidity of the air. It is not unheard-of for people to say "hygrometer"
     when they mean "hydrometer".

Immobilized Electrolyte
    A technique for lead-acid batteries. The electrolyte (the acid) is held in place against the plates
    instead of being a free-flowing liquid. The two most common techniques are gel and glass mat.

Kilowatt
     One thousand watts. Equivalent to about 1.34 horsepower.

L-Post
      A style of battery terminal, shaped like an L, with a flat vertical part to which the cable is
      bolted. See terminal styles for comparison.
Lead-acid
      A technique for rechargable batteries. Electrodes of lead oxide and metallic lead are separated
      by an electrolyte of sulfuric acid.
LiON, LiIon
      Lithium ion. A technique for rechargeable batteries. Instead of using metalic lithium as the
      anode, lithium ions are added to a carbon electrode.
Lithium
      A light metal, atomic number 3. Used in advanced rechargeable batteries.
Lithium Polymer
      A technique for rechargeable batteries. The lithium anode is separated from the cathode by a
      thin polymer electrolyte.


NiMH



                                         Page 37 of 41
                                  Gas2Electric - Electric Car Conversion Guide
        Nickel Metal Hydride
Nicad
     Nickel Cadmium. (historical note, Nicad is/was a registered trademark, but has effectively
     passed into the public domain, like aspirin.)
Nickel Cadmium
     "Old" rechargeable battery technology. For many years, rechargeable dry cell meant nickel-
     cadmium. Recently, newer technologies such as nickel-metal hydride have mostly replaced
     nicad, since they have better energy characteristics and don't contain toxic cadmium. The
     battery has a nickel-hydroxide cathode, a cadmium anode, and aqueous potassium hydroxide
     electrolyte. Saft is a leading manufacturer of nickel-cadmium batteries for EV applications.
Nickel Metal Hydride
     A technique for making rechargeable batteries. NiMH batteries are common in laptop
     computers and cellular phones. The battery is similar to nickel-cadmium but uses an anode of a
     metal hydride; a variety of metal alloys are used.

Optima
     Manufacturer of sealed lead-acid batteries: the Red Top and Yellow Top.
Ovonics
     Division of Energy Conversion Devices, makes nickel metal-hydride batteries.

Peukert's equation
A formula that shows how the available capacity of a lead-acid battery changes according to the rate
of discharge. The capacity of a battery is expressed in Amp-Hours, but it turns out that the simple
formula of current times hours doesn't accurately represent the situation. Peukert found that the
equation:
C = In T
fits the observed behavior of batteries. "C" is the theoretical capacity of the battery, "I" is the current,
"T" is time, and "n" is the Peukert number , a constant for the given battery. The equation captures the
fact that at higher currents, there is less available energy in the battery.
Peukert number
A value that indicates how well a lead-acid battery performs under heavy currents. The Peukert
number is the exponent in Peukert's equation. A value close to 1 indicates that the battery performs
well; the higher the number, the more capacity is lost when the battery is discharged at high currents.
The Peukert number of a battery is determined empirically. For Peukert numbers for typical EV
batteries, see Uve W. Rick's Battery Page.
Power-Sonic
        Maker of lead-acid batteries.

Red Top




                                           Page 38 of 41
                                  Gas2Electric - Electric Car Conversion Guide
      A sealed battery made by Optima, so-called because of the color of its case, it is not the official
      product name. The red top is a starting battery, sometimes used in racing applications. It is not
      designed as a traction battery
Reserve Capacity
      A performance rating for automobile starting batteries. It is the number of minutes at which the
      battery can be discharged at 25 Amps and maintain a terminal voltage higher than 1.75 volts per
      cell, on a new, fully charged battery at 80degrees Fahrenheit(27C).

SG
      Specific Gravity. A specific gravity of 1.300 is sometimes written as 1300SG, multiplying by
      1000 to avoid the use of fractional parts.
SLI battery
      Starting, Lighting, and Ignition battery, a battery designed for use in a conventional gasoline
      automobile. An SLI battery is designed to give a lot of current during starting, but then to be
      recharged immediately by the car's alternator. Deeply discharging an SLI battery will greatly
      shorten its life. SLI batteries are sometimes used in electric vehicles, especially for racing, but
      are generally not considered suitable because of their short cycle life.
SOC
      State of Charge
Saft
      Manufacturer of Nickel-Cadmium, Nickel-Metal Hydride, and Lithium Ion batteries.
See Also
      Lead Industry Associates http://www.leadinfo.com/USES/battery.html
      Delco's battery glossary: http://www.apaa.org/delco/glossary.html
      Uve W. Rick's battery page
      Mike Thompson's battery information page
      SAFT AG
Specific Gravity
      The density of a material, expressed as the ratio of the mass of a given volume of the material
      and the mass of the same volume of water; a specific gravity greater than 1 means heavier than
      water, less than 1 means lighter than water. The specific gravity of the electrolyte in a battery
      can be used to measure the state of charge of the battery.
Spiral-Wound
      A particular design for the electrodes in a lead-acid battery. Instead of having the electrodes as
      flat plates, the electrodes are rolled up in a spiral, like a cinnamon roll. The Optima is an
      example of a spiral-wound battery.
State of Charge
      The amount of electrical charge in the battery, expressed as a percentage of the difference
      between the fully-charged and fully-discharged states.
Starved Electrolyte




                                          Page 39 of 41
                                 Gas2Electric - Electric Car Conversion Guide
      A technique for "maintenance free" lead-acid batteries. These batteries are less prone to gassing,
      so they don't require frequent checking and addition of water. "Starved" because the battery
      contains just enough electrolyte to provide the necessary chemical reaction, as opposed to the
      older "flooded" arrangement which contains considerably more electrolyte than needed to make
      the rated amp-hour capacity.



Terminal styles
     Lead-acid batteries are made with several different styles for the posts that connect to the
     cables. The most common styles are




                 "Automotive" -- the round post familiar on starting batteries in gas-powered cars.
                 The cable lug fits around the terminal.



                 "Universal" -- Like an automotive post, with an extra stud in the center of the post.
                 The cable lug fits over the stud and a nut holds them together



                 "L" -- A flat tang with a hole through it. A bolt through the hole connects the
                 terminal to the cable lug.




      There is considerable difference of opinion as to which style is "best".

Traction Battery
      A battery designed to be used to provide the power to move a vehicle, e.g. to be used in an
      electric car.
Trojan
      Manufacturer of flooded cell traction batteries. Popular and (relatively) inexpensive, Trojans
      seem to be the default choice for converters.

Universal post




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                                 Gas2Electric - Electric Car Conversion Guide
      A style of battery terminal, with a round post similar to the automotive post, but with a threaded
      stud in the center of the post. See terminal styles for comparison.

VRLA
     Valve-Regulated Lead Acid
Valve Regulated
     A technique for making lead-acid batteries. Instead of simple vent caps on the cells to let gas
     escape, VRLA have pressure valves that open only under extreme conditions. Valve-regulated
     batteries also need an electrolyte design that reduces gassing, usually involving a catalyst that
     causes the hydrogen and oxygen to recombine into water.

W
      Watt
Wh
      Watt-hour
wh/kg
      Watt-hours per kilogram, unit of energy density.
wh/lb
      Watt-hours per pound, unit of energy density.
Watt
      Unit of electricity, the rate at which work is done. The equation is Watts = Volts x Amps. One
      watt is equivalent to about 0.00134 horsepower.
Watt-hour
      Unit of electrical energy, or work. 1 watt expended continuously for 1 hour equals 1 watt-hour

Yellow Top
     A sealed battery manufactured by Optima, so-called because of the color of the case, it is not
     the official product name. The Yellow Top is designed to be a traction battery. A relative
     newcomer to the market, the yellow top is popular in some circles because it can deliver high
     currents, providing good acceleration.

X-hour rate
     The discharge rate of a battery is usually quoted in the number of hours that the battery will last
     at that current. So at the 6-hour rate, the battery can produce current for 6 hours. Same as C6.




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