Battery Charging; Frozen Electrolyte; Battery Storage; Discharge/Charge Chemical Action - Jeep 1979 CJ-5 Technical & Service Manual

BATTERIES 1D-3
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Check the external condition of the battery and the
cables periodically.
The holddown should be tight enough to prevent the
battery from shaking which can cause damage to the
battery case.
Take particular care to see that the top of the battery
is free of acid film and dirt between the battery termi-
nals. For best results when cleaning the battery, wash
with a diluted ammonia or soda solution to neutralize
any acid present and then flush with clean water.
CAUTION: Keep filler caps tight so that the neutral-
izing solution does not enter the cells.
To ensure good contact, the battery cables must be
tight on the battery posts. Check to be sure the terminal
clamp has not stretched. This could cause the clamp
ends to become butted together without actually being
tight on the post. If the battery posts or cable terminals
are corroded, disconnect the cables by loosening the
terminal clamp bolt and remove the clamp with the aid
of a puller. Do not twist, hammer or pry on the cable to
free it from the battery post. Clean the terminals and
clamps with a soda solution and a wire brush. Connect
the cables to the battery posts, and apply a thin coat of
grease. Inspect the battery negative cable and body
ground cable for good connection and condition.
Frozon Electrolyte
A 3/4-charged battery is in no danger of damage from
freezing. Keep batteries at 3/4 charge or more, espe-
cially during winter weather.
Replace the battery if the electrolyte is either slushy
or frozen. A battery with this condition, depending on
the severity of the freeze, may accept and retain a
charge and even perform satisfactorily under a load test.
However, after 120 to 150 days in service, a reduction in
capacity and service life will become apparent as the
individual plates lose their active material.
CAUTION: Do not attempt to charge or use a booster
on a battery with frozen electrolyte as it may cause the
frozen battery to explode.
Freezing Temperature Chart
Specific Gravity
(Corrected to 8 0 ° F)
Freezing Temperature
1.270
- 8 4 ° F
1.250 - 6 2 ° F
1.200
- 1 6 ° F
1.150
+ 0 5 ° F
1.100
+ 1 9 ° F
6 0 3 3 9
Battery Storage
All wet batteries will discharge slowly when stored.
Batteries discharge faster when warm than when cold.
For example, at 100°F (37.8°C), a normal self-discharge
of 0.0024 specific gravity per day could be expected. At
50°F (10°C), a discharge of 0.0003 specific gravity would
be normal. Refer to Self-Discharge Rate chart.
Before storage, clean the battery case with a baking
soda solution and wipe the case dry. When storing a
battery, charge fully (no change in specific gravity after
three readings taken one hour apart) and then store in
as cool and dry a place as possible.
Fully charge a stored battery before putting it into
service. Refer to R e p l a c e m e n t for i n s t a l l a t i o n
procedures.
Self-Discharge Rate
Temperature
Approximate Allowable
Self-Discharge Per Day
For First Ten Days
100°F (37.8°C)
8 0 ° F (26.7°C)
5 0 ° F (10°C)
0.0024 Specific Gravity
0.0009 Specific Gravity
0.0003 Specific Gravity
6 0 3 3 8
CHARGING
lisclarge Cleiioal Action
A cell is discharged by completing an external circuit
such as cranking a starter motor. Sulfuric acid, acting
on both positive and negative plates, forms a new chem-
ical compound called lead sulfate. The sulfate is supplied
by the acid solution (electrolyte). The acid becomes
weaker in concentration as the discharge continues. The
amount of acid consumed is in direct proportion to the
amount of electricity removed from the battery. When
the acid in the electrolyte is partially used up by com-
bining with the plates and can no longer deliver elec-
tricity at a useful voltage, the battery is said to be
discharged.
The gradual weakening of the electrolyte in propor-
tion to the electricity delivered allows the use of a hydro-
meter to measure how much unused acid remains with
the water in the electrolyte. This information then can
be used to determine approximately how much electrical
energy is left in each cell.
Charge Chemical Action
The lead sulfate in the battery is decomposed by pass-
ing a current through the battery in a direction opposite
to that of the discharge. The sulfate is expelled from the
plates and returns to the electrolyte, gradually restoring
it to its original strength. Hydrogen and oxygen gases
are given off at the negative and positive plates as the
plates approach the fully charged condition. This is
caused by an excess of charging current not totally ac-
cepted by the plates. A perforated filter and a relief
valve in each cap relieve excess gases.