The Automotive Battery

Construction and Service

After studying this chapter, you should be able to:

1. Discuss the construction and operation of a lead-acid storage battery.

2. Describe the chemical actions in the battery during charge and during
discharge.
3. Define and discuss battery ratings.
4. Explain why battery terminal voltage varies with temperature,
charging rate, discharge rate, and state of charge of the battery.
24-2 CHEMICALS IN BATTERY
24-1 THE BATTERY The chemicals in the battery are sponge
Battery (Fig. 24-1) supplies current to lead is solid, lead oxide (a paste), and
operate the starting motor and the ignition sulfuric acid (a liquid). These three sub-
system when the engine is being started. It stances are made to react chemically to
also acts as a voltage stabilizer by produce a flow of current. The lead oxide
supplying current for the lights, radio, and and sponge lead are held in plate prides to
other electrical accessories ‘when the form positive and negative and negative
alternator is not handling the load. The plates (Fig. 24-5).
battery is an electrochemical device. This The plate grid is a framework of
means it uses chemicals to produce lead alloy with horizontal and vertical
electricity. The amount of electricity it can bars. The plate grids are made into
produce is limited. As the chemicals in the plates by applying lead oxide paste.
battery are “used up” the battery runs down, The horizontal and vertical bars hold
or is discharged. It can be recharged by the paste in the plate.
supplying with electric current from a After the plates are assembled into
battery charger, or a vehicle alternator can the battery is given a “forming”
recharge it. The “used up” chemicals are charge. This changes the lead oxide
then returned to their original condition, so paste in the negative, or minus,
the battery becomes recharged. plate to sponge lead. It changes the
lead oxide paste in the positive, or
plus plate to lead peroxide.
24-3 BATTERY CONSTRUCTION In the
battery, several similar plates are
1
properly spaced and welded, or lead- the internal connections are in place the
burned, to a strap. This forms a plate cover is put (Fig. 24-1 to 24-3). In many
group. Plates of two types are used, one batteries, the cover has openings through
for the positive plate which liquid can be added water; the filler
group, the other for the negative plug or vent caps are removed. After the
plate group. A positive plate group is liquid is added and the battery is given an
nested with a negative plate group. initial charge. It is ready for operation
Separators are placed between the Maintenance-free batteries have no vent
plates to form an element (Fig. 24-3). The caps
separators hold the plates apart so that
they do not touch. At the
same time the separators are porous
enough to permit liquid in circulate
between the plates. Wooden sheets,
spun glass matted into sheets and
porous sponge rubber sheets have been
used as separators. Late- model
batteries have separators made of acid-
resistant polyvinyl chloride on Fig.24-2 phantom view of a 12-volt
polyethylene saturated cellulose. battery with the terminals in the state
of the battery (Division of General
Motors Corporation).

Fig. 24-1 Two types of automotive

batteries. The left battery it caps which
can be removed to check the battery
state charge and add to
water. If needed the right battery with Fig.24-3 Partly cut away and
side terminals is a sealed maintenance disassembled 12-volt battery(Ford
free type and requires no water. The Motor Company)
Some batteries have the two main
charge indicator in the top shows the
terminals on the battery cover as in
state of charge of the battery.
The elements are placed in cells in the 24.3. Other batteries have the
battery case. Then heavy lead terminals in the side of the battery
connectors are attached to the cell (Ford Motor Company) cover as in Fig
terminals to connect the series. After 24.3 Other batteries have the
terminals in the side of the battery
case as in Fig 24.2 Figure 24.4
shows how the cables are connected to a
side terminal battery. It also shows the
battery-mounting
arrangement. On a top-terminal attention expect for an occasional check
battery the positive terminal (or of the connections and the built-in
“post”) is larger than the negative charge indicator (Fig
post. 24-1 right) other batteries have vent caps
Many batteries are the maintenance- (Figs 24-3 and 24-4), which can be
free type. They require no special removed. Then you can look
2
down into the battery cells to see whether battery (Cadillac Motor Car Division of
they need water. Also a hydrometer can General Motors Corporation) from the
be used to check the battery charge. terminal where chemical activity has
collected them. They now through the
24-4 CHEMICAL ACTIONS IN circuit to the other from terminal where
BATTERY the chemical activity has removed them.
The liquid in a battery is called the Chemical activities now begin again so
electrolyte. It is made up of about 40 the tire
percent sulfuric acid and about 60 2-volt pressure is maintained. The
percent water (in a fully charged battery) current now continuous. The chemical
when sulfuric acid is placed between the action use up the sponge lead, lead
pieces chemical actions takes place. peroxide and sulphuric acid. After a
These actions removed electron from certain amount of current has been
one group of plates withdrawn the battery is discharged (“run
and collect them at other. This creates a down or dead”). It is not capable of
pressure of 2.1 volts between the two delivering any additional current. When
terminals of the battery cell. If any circuit the
no connects the two terminals, no further battery has reached this state, it may be
chemical activity takes place. However recharged. This is done by supplying it
when the two terminals do become with a flow of current
connected by an electric circuit, from some external source. The external
electrons (current will flow. source forces current back through the
battery.This reverses the chemical
activity in the battery.The plates are
restored to their original composition and
battery becomes recharged.It is then
ready to deliver additional current.
The Chemical action that take place are
They flow Fig 24.4 Cable rather complicated.The sponge
connections for a side-terminal lead(negative plate) and lead
peroxide(positive plate) change to lead
sulphate during the discharge
process.The sulphate comes from
sulphuric acid. The electrolyte loses acid
and gains water as the sulfate goes into
the plates. Therefore discharging the
battery changes the two different
chemicals in the battery pieces to a third
chemical lead sulfate. Recharging the
battery changes the lead sulfate back to
sponge lead in the negative plates, and
to lead peroxide in the positive plates.
Meantime the sulphuric acid
reappears in the electrolyte of the special applications use 24-volt batteries:
battery. these special-purpose batteries have 12
cells.
0
24-5 CONNECTING CELLS Automotive Although a battery cell at 80 F will test
batteries are usually 12 volts: units. on open circuit about 2.1 volts when fully
There are six cells in the charged common practice is to cell 2
12-volt battery. The six cells are volts. Therefore a six-cell battery is said
connected in series. In series to be a 12 volts
connections, the voltages add. Some
3
battery rather than a 12.6 volt compare hour compare. This is the
battery. amount of current time a battery can
deliver for 2v hours witness the cell
24-6 BATTERY RATINGS voltage dropping below 1.75 volts with a
0
The amount of current that a battery can electrolyte temperature 80 F
0
deliver depends on the total area and 26.7 C. For example battery that can
volume of active plate material. deliver current of 5 amperes lo: 20 hours
It also depends on the amount and is rated as having a 100. amperes hour
strength of electrolyte. This is the capacity 120x5= 100
percentage of sulfuric acid in the
electrolyte. Factors that influence battery 3.Cold Cranking Rate- One of the two
capacity – its ability to deliver current – cold-cranking rate if the number of
include the number of plates, the cell appears that a battery can deliver for 30
size, and the quantity of electrolyte. The spreads when at OFF 178’C without the
ratings most commonly used in referring cell volt ages ladling below 1.2 volts. A
to typical rating for a battery with a reserve
battery capacity are discussed capacity of
below. 125 minutes would be 430 amperes.
This figure indicates the ability of the
1.Reserve Capacity- Reserve capacity is battery to crank: the engine at low
the length of time in a minute that a fully temperature. The second cold- cranking
0
rate is measured at – 20 F
charged battery at 0
0 – 28.9 C. In this the final voltage is
80 F can deliver 25 amperes. A typical
allowed to drop to 1 volt per cell. A
rating would be 125 minutes. This figure
typical rating for a battery with a reserve
tells how long a battery can carry the
capacity of 125 minutes would be 320
electrical operating load if the alternator
amperes.
quits.
2.Ampere Hour Capacity- An older in the
20-hour rate also called the 4.Watts Delco- uses an additional
rating – watts. This is roughly
equivalent to the battery cold-
cranking rating.

24.7 BATTERY EFFICIENCY

The ability of the battery to deliver
current varies within wide limits. It
depends on temperature and rate of
discharge. At low temperature chemical
activities are greatly reduced. The
sulfuric acid cannot work as actively on
the plates. Therefore the battery is less
efficient and cannot supply as much
current for as long a time. High rates of
discharge will not produce as many
ampere-hours as low rates of
discharge. At high discharge rates the battery temperatures. However these are
chemical activities take place only on only approximations.
the surfaces of the plates. They do not
have time to penetrate the plates and
to use the materials below the plate Efficiency Battery
surfaces. The chart below relates Percent Temperature
battery efficiency to Deglees F(C)
100 80|[26.7]
4
 65 32[0] c. Decreasing temperature. Lower
50 0[-17.8] battery temperatures resource a higher
10 -45[-42.8] voltage to maintain charging rate
2. The terminal voltage of a battery that
24-8 VARIATIONS IN TERMINAL being discharge decreases with: a.
VOLTAGE Increasing discharge rate. As the rate of
Because the battery produces voltage discharge proof or chemical activities
by chemical means voltage varies increase and cannot penetrate plates so
according to a number of conditions. effectively. Therefore voltage reduced.
These conditions and b. Decreasing state or charge. With less
their effect on battery voltage may be of the active mate takes place and
summed up as follows voltage drops.
1. Terminal voltage pattern being c. Decreasing temperature. With lower
charged increases with temperature the chemical activities
a. Increasing charging rate. To cannot go on as effectively and the
increase charging rate (ampere input) voltage drops.
the terminal voltage must go up.
b. Increasing state of charge. As state of
charge goes up voltage must go up to BATTERY MAINTENANCE AND
maintain charging rate For example a SERVICE
voltage of approximately
2.6 volts per cell is required to force a 24-9 BATTERY MAINTENANCE Complete
current through a fully charged battery. battery maintenance includes the following:
This is the reason that voltage regulators
are set to operate at 15 volts – slightly 1. Visually check the battery.
below the voltage required to charge a 2. Check electrolyte level in cells on
fully batteries with caps.
charged battery. This setting protects the 3. Add water if the level is low (vent- cap
battery from overcharge. batteries).
4. Clean off corrosion around battery
terminals and from top of batteries
with top terminals (Fig
24-3)
5. Check battery condition by
testing its state of charge
(explained later).
6. Recharge battery if it is low.

24.10 CAUTIONS FOR BATERY

SERVICE
These are the important cautions to
observe when working with batteries
1. The sulfuric acid in the electrolyte is 2. Gases form in the battery when it is
very corrosive. It can destroy most being charged. These gases
things it touches it will eat holes in are highly explosive. Never light a
cloth. It can cause match or a cigarette when
serious burns if it gets on your skin. If working around batteries. You
it gets in your eye protection when might cause an explosion that
working around batteries. If you get could seriously harm you.
battery acid on your skin. Flush it out 3. The battery can supply a very high
at once with water over and over Fig current. Never wear rings bracelets,
2-12 watches or hanging necklaces when
Then get to a doctor at once. working around batteries. If a metal
5
 ring or other ornament should battery terminals and tops missing vent
accidentally short a battery a very high caps and loose or missing hold- down
current will flow. This could turn the clamps. Leakage causes white corrosion
ring white-hot in an instant and you on the battery carrier and surrounding
could get a serious burn. metal parts. Leakage is due to a crackled
4. When jump-starting a car follow the battery case or top. The remedy is to
instructions and caution in 25- install a new
9. A wrong step can damage the battery.
electrical system and cause you to The top of the battery can be crackled if
get hurt. the wrong wrench is used to disconnect
5. When disconnecting a battery always or install cable clamps top terminals. The
disconnect the cable from the case can be cracked if the hold-down
grounded the insulted clamps are over tightened.
terminal or any terminal or wire that
is hot (connected to the insulted 24.12 CHECKING ELECTOLYTE
terminal you will not be making a LEVEL AND ADDING W ATER
direct short across the battery. On vent cap batteries the electrolyte
level can be checked by removing
24.11 VISUAL INSPECTION OF the caps, Some batteries have a spilt ring
BATTERY which indicates the electrolyte level (Fig
Look for signs of leakage a crackled 24.5). If the level is low add water. Some
case or top corrosion buildup on batteries have an electrolyte-level
indicator (a “Delco Eye”). It gives a visual
indication of the electrolyte level (Fig
24.6). Black means the level is okay.
White
means the level is low.

Careful : Do not add too much water. This

can cause electrolyte to leak out and
corrode the battery carrier and other
metal nearby.

24.13 CLEANING CORROSION

OFF BATERY
On batteries with the terminals on top the
terminals and cable clamps sometimes
corrode. This corrosion can be cleaned
off disconnecting the clamps and
cleaning the terminal
and clamps with special wire brushes
(Fig 24-7). Battery-top corrosion can
be cleaned off by brushing the top
with baking soda solution. After the
foaming stops,

6
flush off the battery top with water.
Terminals can be coated with an anti
corrosion compound to retard corrosion.

24.14 CHECKING BATTERY

CONDITION
On vent-cap batteries, the battery
can be checked with a hydrometer to
determine its condition. Other methods
use testing instruments, as explained Fig 24.5 Appearance of the electrolyte
later. These other and split ring when the electrolyte is too
methods are for the maintenance- iree low and when it is correct (Delco-Remy
batteries but can also be used on the Division of General Motors Corporation)
vent-cap type. of the electrolyte (Fig 24.9). The height of
the stem above the electrolyte tells you
24.15 HYDROMETER TEST the battery state of charge. Here is what
The hydrometer tests the specific gravity the readings mean.
of the battery electrolyte. There are two 1.265 – 1.299 Fully charged battery
types of hydrometer (Fig 24-8). One uses 1.235 – 1.265 Three-fourths charged
a series of plastic balls, the other a glass 1.205 – 1.235 One half charged
float with a stem on top. To use a ball- 1.170 – 1.205 One fourth charged
type hydrometer, stick the rubber tube in 1.140 – 1.170 Barely operated 1.110
the electrolyte. Then squeeze and 1.110 - 1.140 Completely charged.
release the rubber bulb. This draws
electrolyte up into the glass tube. The
number of balls that float tells you the
battery state of charge.
If all ball float the cell fully charged. If
none float the cell is discharged.

Careful : Do not drip electrolyte on the

car or on yourself Electrolyte will damage
the paint on the car and eat hole in your
clothes. See caution 1 in
24-10

The float type hydrometer (right in Fig

24-8) has a float with a stem that sticks
up above the electrolyte level in tubs.
They float stem is marked to indicate the
spare.

7
 Fig 24.7 Using battery terminal
brush to clean the battery terminal
posis and cable clamps Black Motor
Fig 24.6 A battery cell with Division of General Motor
electrolyte level indicator(top).The Corporation
electrolyte at one correct level
and(bottom)low electrolyte level.
(Delco-Remy Division of General
Motor Corporation).

If some cells test considerably lower

than others, it means there is
something wrong with those cells. It
could be that a cracked case has
allowed electrolyte leakage or
perhaps there is internal damage to
the plates or separators. If the
variation is only a few specific-gravity
points, then there is probably no
cause for alarm. But if the low cells
measure 50 points lower then those
cells are defective and the battery
should be replaced.
Some 12-volt batteries for passenger
cars have a slightly lower specific Fig.24-8 Battery hydrometers to
gravity when charged For example check electrolyte specific gravity.
one type is fully charged with a
specific gravity of 1.270. Other
batteries such as those used in hot
climates have a specific gravity of
1.225 when fully charged.
The decimal point is not normally
referred to in a discussion of specific
gravity. For example “twelve twenty
twenty-five means 1.225 and eleven
fifty means 1.150.
 battery wears out and must
be replaced.
24-18 LOSS OF
SPECIFIC GRAVITY
FROM SELF-
DESCHARGE
Fig.24-9 Using a float hydrometer If a battery stands idle for a long
to check a battery cell. Reading time, it will gradually run down. This
must be taken at eye level. The is due to the chemical actions
higher the float stem stick out of the between the electrolyte and the
electrolyte, the higher the state of battery plates. The higher the
charge of the battery. temperature the more rapid this
self- discharge.
24-16 VARIATIONS OF SPECIFIC 24-19 FREEZING
GRAVITY W ITH TEMPERATURE TEMPERATURE OF
The electrolyte thickens (gains ELECTROLYTE
specific gravity) as it coos. It loses
specific gravity, as it gets hot. On The higher the specific gravity of the
the ball hydrometer this is not electrolyte the lower the
important. But on the float temperature must be before the
hydrometer electrolyte freezes. The battery
correction of the specific gravity must be kept sufficiently charged in
reading should be made if the cold-weather to prevent freezing.
electrolyte temperature is well Freezing may
0 0 run the battery (Fig 24-10).
above or below the 80 F [27 C]
standard. Specific gravity changes
0
about four points for every 10 F 24-20 CHARGE INDICATOR ON
change in temperature. A reading of MAINTENANCE FREE
1.250 at BATTERIES Many maintenance
0 0
120 F (48.9 C ) would correct to free batteries have a charge
1.266 (add 0.016 or 4x 0.004) A indicator on their top (Fig 24-11)
0 0
reading of 1.230 at 20 F (-6.7 C) The appearance of the charge
would correct to 1.206 (subtract indicator shows the state of charge
6x of the battery.
0.004 or 0.024). CAUTION If the charge indicator
shows yellow do not attempt to
24-17 LOSS OF recharge or test the battery. It is
SPECIFIC GRAVITY close to failure and should be
FROM AGE replaced. Never attempt to jump-
As a battery ages the electrolyte start the car if the charge
gradually loses specific gravity. indicator shows yellow (25-9)
This loss is due to aging and
nothing can be done about it. 24-21 BATTERY-CAPACITY
Eventually the (HIGH DISCHARGE) TEST
For this test a special tester is
used. It places a load on the battery
voltage can be measured while a
Specific gravity Freezing 24-22 BATTERY SERVICE
Temperature Battery service can be divided into
Degrees F(C) four parts visual inspection testing
1.100 18 [-8.2] charging and care of batteries in
1.100 1[-17.2] stock.
1.200 -17[-27.3]
1.320 -31[-35] 24-23 BATTERY TESTING AND
1.260 -75[-59.4] ANALYSIS
1 . 300 -95[-70.5] Battery testing includes a check of
the condition of the battery. It should
Fig 24-10 Specific gravities and also include analysis of any
freezing temperatures for battery abnormality found so that corrections
electrolyte. can be made. This will prevent a
repetition of trouble. Following are
various battery troubles and their
possible causes. These apply mainly
to vent-plug batteries
1.Overcharging -If the battery
frequently requires after, it is
probably being over being
overcharged. Too much current is
Fig 24-11 being supplied to the battery. This is
Appearance of the charge indicator in the a damaging condition that overworks
top of some maintenance-free batteries (A) the active materials in the battery
If the green dot shows the battery is charged
(B) If the indicator shows black the battery and shortens battery life. In addition
low and should be charged before testing overcharging causes more rapid loss
(C) If the indicator shows light yellow the of water from the battery electrolyte.
battery is dead and should be discarded. Unless this water is replaced
High current flowing out of the frequently the electrolyte level is
battery. Specifications for this test likely to fall below the tops of the
vary. Follow the procedure in the plates. This exposes the plates and
tester operating instructions. the separators to the air and may run
Specifications for voltage and battery them. Also battery overcharge
capacity are in the manufacturer’s causes the battery plates to buckle
service manual. In general a load of and crumble. Therefore a battery
three times the battery ampere-hour subjected to severe overcharging will
capacity is placed on the battery. soon be ruined Where overcharging
You can also use one-half of the is experienced or suspected the
0 0
cold-cranking rate at 0 F (- 17.8 C). charging system should be checked.
At the end of 15 seconds a good It should be serviced if necessary to
battery should show a voltage of 9.6
prevent overcharging (Chap 26).
volts or together. If the voltage is
2.Undercharging- If the battery is
less than 9.6 volts and the battery
has removable vent plugs check the discharged, it should be recharged
specific gravity of each cell if there is as outlined later in this chapter. In
more than a 50-point difference addition an attempt should be made
between cells replace the battery.
to determining the cause of the a. Charging-system malfunctioning.
trouble. It could be caused by: b. Defective connections in the
10
10
 charging circuit between the spraying of battery electrolyte is
alternator and the battery. natural as the battery is being
c. Excessive load demands on the charged. The battery holder may
battery. become corroded from the effects of
d. A defective battery. the electrolyte. Such corrosion may
e. Permitting the battery to stand be cleaned off, with the battery
idle for long periods so that it self removed. Use a wire brush and a
discharges excessively. solution of baking soda and water.
In addition an old battery may have a 8.Dirty Battery Top- The top of the
low specific-gravity reading because battery may become covered with
it is approaching failure. dirt and grime mixed with electrolyte
3. Sulfation -The active materials in sprayed from the battery. This
the plates are converted into active should be cleaned off periodically
material during recharge. However if (24.13).
the battery stands for long periods in 9.Discharge to Metallic Hold-
a discharged condition the lead Down-
sulfate is converted into hard If the hold down clamps are the
crystalline substance. This uncovered metallic type, a show
substance is difficult to reconvert into discharge may occur from the
active materials by normal charging insulted terminal to the hold down
processes. Such a battery should be clamp. This is more apt to occur with
charged at half the normal rate for 60 a dirty battery top across which
to 100 hours. Even though this long current can leak. The remedy to
charging period may convert the keep the battery top clean and dry.
sulfate to active material, the battery
may still remain in a damaged 24-24 REMOVING AND
condition. The crystalline sulfate, as REPLACING BATTERY
it forms tends to break the plate To remove a battery from a car first
grids. take off the grounded battery-
4.Cracked Case- A cracked case terminal cable clamp. This prevents
may result from excessively loose accidental grounding of the insulted
tight hold-down champs, from battery terminal when it is disconnected To
freezing or from flying stones. remove a nut-and-bolt type of cable
5.Bulged Cases - Bulged cases loosen the clamp out about 3/6 inch
result from tight hold-down clamps (9.5 mm) Use a box wrench or
from high temperatures. special cable pliers. Do not use
6.Corroded Terminals and Cable ordinary pliers or an open-end
Clamps -The condition occurs wrench. Either of these might break
naturally on batteries. Excessive cell cover when swung ground. If the
corrosion should be removed from clamp sticks, use a clamp puller. Do
cable clamps and terminals(24-13) not use a screwdriver or bar to pry
7.Corroded Battery Holdo- Some on the clamp. This could damage the
battery cell all or cover. To detach
the spring-ring type of clamp
squeeze the ends of the rings apart
with Vise-Grip or Cannel lock pliers.
After the grounded cable is insulted-terminal cable. Clean both
disconnected disconnect the battery terminals and cable clamps
11
11
(24.7) Loosen the battery hold- charging current. At the same time,
downs and take out the battery. the current input gradually tapers off.
When installing a battery do not When the battery is fully charged the
reverse terminal connections. current input has been reduced to a
Reconnect the insulted-terminal few amperes. The battery electrolyte
cable Apply corrosion inhibitor to temperature must remain within
clamps and terminals. Install and limits. If the battery electrolyte
tighten the hold-downs. Avoid temperature increases greatly the
overtightening. resistance of the battery will remain
Careful -Make sure the cable clamps low. Then the battery will be
are light and make good connections damaged by overcharging unless it
with the terminal posts (top terminal is quickly removed from the charger.
battery) If the jaws of fine clamp Before charging battery check the
touch together the clamp is not tight electrolyte level If the level is low, the
on the post. Shave the clamp jaws battery can be damaged. If the level
with a file until there is a gap when is too high the electrolyte can
the clamp is installed. overflow because of gassing and
heat. Here are cautions to observe.
24-25 BATTERY ADDITIVES 1. The gases released by batteries
Certain chemical compounds when under charger are very explosive.
added to the battery cells are Be sure the area is well
supposed to restore a battery to a ventilated. Do not smoke on have
charged condition. Such chemicals open flames around charging
should never added the battery. batteries This could cause an
Their use may void the battery explosion
guarantee and cause battery failure. 2. Be sure to disconnect the battery
24-26 BATERY SLOW CHARGING ground step if the battery being
Two methods of slow charging charged in a car Otherwise you
batteries are in use, the constant- can damage the electrical
current and the constant-voltage equipment in the car
methods. In the constant-current 3. Most manufacturers
method, the current input to the recommended leaving the cell
battery is adjusted to the caps in place. But make sure the
manufacturer’s specifications. The vent holes are open. Cover the
charging is continued until the caps with a cloth during the
battery is gassing freely and there is charging procedure Some
no rise in specific gravity for 2 hours. manufacturers recommended
In the constant-voltage method, the removing the caps and coving the
charging voltage is held at a openings with a cloth
constant value. The battery, as it 4. Do not charge a battery that is
approaches a charged condition frozen. It could explode
increases in resistance to the 5. Always wear some type of eye
protection
6. If the charger indicator of a
maintenance-free battery shows
yellow on clear, do not charge it.
The electrolyte level is low, and explosion. The battery should be
charging it could cause an discharged
12
12
7. Do not turn the charger on until Likewise a badly sullated battery
the charger cables are connected should not be quick charged. Such
to the battery. Turn the charger batteries may be near failure but
off before disconnecting the they may give additional service if
cables slow charged However quick
8. Check the specific gravity and charging might damage them further.
temperature of the electrolyte During quick charging check the
periodically during charge. If the color of the electrolyte Stop charging
0
temperature goes above 125 F if it becomes discolored as a result of
0
(51.7 C) stop the charge.
the stirring up of washed-out active
9. The battery is fully charged when
the specific gravity shows no plate material Likewise cell voltages
increase for 3 hours. Also the should be checked every few
cells should be gassing freely minutes Charging should be stopped
10. After charging, wash and dry it cell voltages vary more than 0.2
the battery top. This removes volt.
any electrolyte that might have Careful -When quick charging a
spewed out during charge. battery in a car disconnect the
battery ground strap to protect the
24-27 QUICK CHARGERS electrical system from damage due
The quick charger can be wheeled to high voltage. If the charge
up to the car and connected to the indicator in a maintenance free
battery in the car (Fig 24.12) Here battery shows yellow do not try to
are some special points to watch quick charge it(24-20)
when using a quick charger. These
chargers can supply a fast charge of
up to 100 amperes (for some types)
Normally you would set the charging
rate for about 40 to 50 amperes and
charge the battery for about 30 to 45
minutes. This boosts the battery with
up to 38 ampere does not go above
0 0
125 F (51.7 C)
Quick charging usually cannot bring
the battery to full charge in a short
time. To bring it up to full charge, the
battery should be given a slow 24.12 Quick charger connected to a
charge after the quick charge. battery in the car. The grounded
Careful -A battery with discolored battery cable should be
electrolyte (from cycling) or with disconnected before charger cables
gravity readings more than 25 points are connected( Chryster
apart should not be quick charged. Corporation).

A very low battery may not accept a

fast charge. The electrolyte in a very
low battery does not have very much
sulfuric acid in it. Therefore, the

13
13
conductivity of the electrolyte is too 2. Remove the lid from the
low to allow a high current to flow electrolyte container. Unfold the
through the battery. You might think top of the plastic bag, and cut a
a battery that refuses to make a high small opening in one corner of
charge is torn out. However, it may the bag
be possible to restore the battery to 3. Use a glass acid-proof funnel and
a charged condition. First slow fill each battery cell. Wear
charge it for a few minutes to see goggles and observe all cautions
whether it starts coming up to already noted regaraging sulfuric
charge. If does, then it can be put on acid. Wait a few minutes and
fast charge. then add more electrolyte if
necessary. Some electrolyte will
24-28 CARE OF BATTERIES IN probably be left. Do not attempt
STOCK to use it all. Do not overfill the
Wet batteries (new batteries shipped battery.
with electrolyte in them) their 4. Before discharging the container,
perishable. They are subject to self- empty it Rinse the bag thoroughly
discharge. If allowed to prevent this with water. Otherwise someone
batteries in stock should be who handles the carton might be
recharged every 30 days. They severely burned.
should not be stacked on top each
other without additional support. The
weight of one battery is enough to
collapse the plate assemblies.

24-29 DRY-CHARGED BATTERIES

Dry-charged batteries contain fully
charged positive and negative plates
but no electrolyte. The batteries are
sealed with rubber or plastic seals
placed in the vent plugs. Since the
batteries contain no moisture
practically no chemical action can
take place in them. This means that
they will remain in good condition for
as long as 36 months.
Dry-charged battery manufacturers
supply ready-mixed electrolyte in
special cartons. The carton contains
an acid proof plastic bag, which
holds the electrolyte. The following
steps are performed to activate a
dry-charged battery
1. Remove the vent plugs, and take
out the plastic seals

14
14
 a. supply current for
cranking the engine
b. supply current when
the charging system
can’t handle the
*****REVIEW QUESTIONS******* complete electrical
Select the one correct. best or load
most probable answer to each c. both of the above
question. You can find the d. neither of the above
answers in the section indicated 5. The length of time in minutes
at the end of each question. that a fully charged battery at
0 0
1.When working around 80 F (26.7 C) can deliver 25
batteries remember that (24- amperes is called the (24-6)
10) a. charging rate
a. battery electrolyte contains a b. reserve capacity
very corrosive acid. c. Cold-cranking
b. explosive gas forms in the rate d. ampere-
battery which it is being charged. hour rate
c. the battery can furnish a very 6. The number of amperes that
high current if it is shorted. the battery can deliver for 30
0
d. all of the above. seconds when it is at 0 F (1-
0
2. When disconnecting a battery 17.8 C) before the battery
always voltage falls to 7.2 volts is called
the (24-
(24-10)
6)
a. remove the vent plugs
a. charging rate
first b. disconnect the
b. reserve capacity
insulated –
c. cold-cranking
terminal cable first
rate d. ampere-
c. disconnect the
hour rate
grounded- terminal
7. If you must add water to
cable first
the battery every few
d. put the transmission in PARK
days, the battery probably
or REVERSE.
(24-23
3. The battery is an
a. overloaded
electrochemical device.
b.
This means that the
overcharged
battery(24-1) a. makes
c. sulfated
chemicals by
d. old
mechanical
8. A loose battery-cable
means
clamp could cause (24-
b. uses chemical action to
23)
provide electricity.
a. battery
c. has curved instead of flat
overcharged b. high
plates d. does not use an
battery voltage c.
electrolyte.
overheating
4.The purpose of the battery is to(24-
d. run down battery
1)

15
15
9. On a top-terminal battery, the
negative terminal post is (24-3)
a. Smaller than the positive
terminal post
b. Larger than the positive
terminal post

16
16
 c. The same size as the
positive terminal post
d. None of the above
10. You can quick charge the
battery at as much as 50
amperes provided (24-27)
a. the electrolyte does not
get too hot
b. you do not charge for
more than 5 minutes
c. you make sure the battery
is fully charged
d. It remains connected to
the electrical system.