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Battery and Charging System


									Battery and Charging System

      Consumer Auto Electrical
            Lecture 2

 Batteries store electrical energy that
 we use to power most of the car
 Batteries store electrons electrically
 They contain lead plates, sulfuric
 acid, and a plastic case
 Sulfuric acid reacts with all metals,
 causing corrosion
Battery Types
   Designed to only power motors for a
   short time (starter), then be recharged
   Completely draining will damage them
 Deep Cycling
   Designed for powering electric motors
   where they are completely drained then
   Stronger design
   More expensive
Automotive Battery Types
 Lead Acid
   Contains 2 types of plates with
   Lower cost
Automotive Battery Types

 Gell Cell
   Has 2 types of lead
   plates wound in a
   Uses an electrolyte
   in gell form
   More expensive than
   lead acid
   More durable than
   lead acid
Automotive Battery Connections
 Post Terminal
   Used in older cars
 Side Terminal
   Used in newer cars
 L Terminal
   Used in boats and equipment
Battery Ratings

 Batteries are rated 4 ways:
   CCA (Cold Cranking Amps)
   CA (Cranking Amps)
   RC (Reserve Capacity)
   AH (Ampere Hour)

 Cold Cranking Amps
 Indicates the ability of a battery to
 deliver a specified current at a low
 It is determined by the amount of
 current a fully charged battery can
 supply for 30 seconds at 0°F without
 the voltage falling below 7.2 Volts

 Cranking Amps
 This is the same test as the CCA
 rating, except it is at a higher
 temperature (32°F instead of 0°F)

 Reserve Capacity
 It determines the time in minutes a
 vehicle can be driven after the
 charging system fails
 The length of time a fully charged
 battery (at 80°F) can supply 25 Amps
 before the voltage falls below 10.5

 Ampere Hour
 The amount of current a fully charged
 battery (at 80°F) can supply for 20
 hours without having the voltage fall
 below 10.5 Volts
Determining Battery Ratings

 Most battery ratings are printed or
 stamped in the top of the battery
 Most have 1 or 2 ratings
Determining Positive and Negative

 In a post type, the
 positive (or +) is
 larger than the
 negative post (or -)
 In the side terminal,
 it is marked POS or
 + for positive and
 NEG or – for
 Corrosion causes many battery
 Corrosion causes a barrier
 between the battery post and the
 When there is a barrier, no
 electrons can flow
 Even though the battery is fully
 charged, it won’t start the car
Eliminating Corrosion

  Wash the top of the battery with hot
  water until all the corrosion is gone
  Remove the negative cable, then
  the positive cable
  Clean the positive post with a
  battery cleaning brush, then the
  battery cable
  The corrosion is gone when the post
  and cable are shiny
Eliminating Corrosion 2

 Connect the positive cable to the
 Clean the negative post and cable
 until clean
 Reconnect the cable to the battery
 Many anticorrosion products are
 available to prevent corrosion
Checking the Battery

 If there is an indicator window,
 look at the color of it
 Green indicates good, dark
 green means it needs a
 charge, and white or
 yellow means it
 needs to be replaced
Checking the Battery 2

 Check the outside of the battery for
 Check the hold down for tightness
 Check for
 cracked or
 broken cables
Checking the Battery 3

 Check the level and condition of
 the electrolyte
Checking Electrolyte

 There should be a mixture of 36%
 sulfuric acid and 64% water in the
 You can measure using a
 It measures the
 weight of the
Checking Electrolyte 2

 Remove covers from battery (if
 Squeeze the bulb
 Lower tube into the electrolyte
 Draw into the hydrometer
 Record reading
 Slowly release electrolyte into battery
 Do Not Splash Electrolyte!!!
Hydrometer Measurements

 Pure water reads 1.000 on a
 A reading of 1.270 means the battery
 is fully charged (36% water, 24%
 A dead battery will read 1.100 (less
 than 15% H2SO4)
Hydrometer Measurements 2
 When you measure the specific gravity
 (weight) of each cell, they must all be
 within 50% of each other
                                  Cell   1
                                  Cell   2
                                  Cell   3
                                  Cell   4
                                  Cell   5
                                  Cell   6
Voltage Tests – Open Circuit
 Turn on the headlights for 2 minutes
 Turn off the headlights and connect a
 voltmeter to the battery, red lead to positive,
 black to negative
 If the battery is good, it will read above 12.2
 If below that, charge
 the battery
Load Test Connections
 Make sure the battery is fully charged
 Connect the red lead or the VAT-40 to
 the positive terminal
 Connect the black lead to the negative
 Clamp the green clamp over the black
VAT-40 Connections
Load Testing
 Turn the Load Increase control until
 the ammeter reads 3 times the amp-
 hour (AH) rating or one-half the cold-
 cranking ampere (CCA) rating
 Hold that reading for 15 seconds
 Read voltmeter
 A good battery will read at or above
 9.6 volts
 Battery should be at 70°F
Case Drain Tests

 Uses a voltmeter with the black lead
 hooked to the negative
 Use the red lead to touch the case in
 the middle of the battery
 It should read less than 0.5 volts
 A larger reading indicates you should
 clean the top of the battery with hot
 water and detergent
Parasitic Drain Test

 Remove the negative cable
 Hook a test light between the
 negative post and the cable
 If the light glows, there is a problem in
 the electrical system
 Look for lights on in the trunk, glove
 box, or dome lights on
Cable Corrosion Test
 Using a voltmeter, hook the black lead to the
 negative post, and the red lead to the cable
 connector while turning on the headlights
 Reading should be 0 volts
 Do the
same with the
positive post
and cable
Charging the Battery - Precautions

 Leave the vent caps in place
 Charge in well ventilated areas
 Keep sparks and flames away from a
 charging battery
 Disconnect the ground wire to
 recharge a battery
Charging the Battery

 Check electrolyte levels, fill as
 Disconnect the ground lead
 Connect the red lead to positive, the
 black to negative
 Turn on the charger
 Make sure it is set to the battery
Disconnecting the Battery Charger

 Turn off the charger
 Disconnect the charger leads
 Reconnect the ground wire
Jumping a Battery

 Make sure the vehicles are not
 touching each other
 Turn the engine off on the car with the
 good battery
 Make sure when connecting the leads
 they are clear of any rotating parts
Jumping a Battery 2

 Connect the read leads to both
 positive posts
 Connect one end of the black lead to
 the negative terminal, the other to the
 cars ground
 After the car starts, disconnect the
 black lead from the ground, then the
 rest of them
Jumping a Car - Illustration
That Concludes Electrical Lecture 2

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