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6D-8
1977 PONTIAC SERVICE M A N U A L
The battery has three major functions in the electrical
system. First, it provides a source of energy for cranking the
engine. Second, it acts as a voltage stabilizer for the electrical
system. And third, it can, for a limited time, provide energy
when the electrical load used exceeds the output of the
generator.
GENERAL INFORMATION
C O M M O N CAUSES OF FAILURE
The battery is not designed to last indefinitely; however,
with proper care, it will provide many years of service.
If the battery tests good but fails to perform satisfactorily
in service for no apparent reason, the following are some of
the more important factors that may point to the cause of
trouble.
1. Vehicle accessories inadvertently left on overnight.
2. Slow average driving speeds of moderate duration.
3. A vehicle electrical load exceeding the generator
capacity, particularly with the addition of after market
equipment such as radios, air conditioning, window defoggers
or light systems.
4. Defects in the charging system such as high resistance,
slipping fan belt, faulty generator, or voltage regulator.
5. Battery abuse, including failure to keep the battery
cable terminals clean and tight, loose battery hold-down, and
failure to properly maintain electrolyte level in the
conventional battery as outlined in Section 0 .
6. Mechanical defects in the electrical system, such as
shorted or pinched wires.
ELECTROLYTE FREEZING
The freezing point of electrolyte depends on its specific
gravity. Figure 6D-8 gives the freezing temperatures of
electrolyte at various specific gravities.
Fig. 6D-8 Freezing Chart
VALUE OF
SPECIFIC
GRAVITY
@
30°F
Since freezing may ruin a battery, it should be protected
against freezing by keeping it in a charged condition.
Antifreeze should never be added to the battery to prevent
it from freezing.
FREEZING
o F
TEM6.
ELECTROLYTE LEVEL
Section
0
has information covering electrolyte level
periodic service for the conventional battery.
Two
precautions should be followed with the conventional battery:
1. Never add electrolyte to the battery. Since only water
evaporates in service, only water should be added.
2. Liquid level should never be allowed to drop below
the level of the plates, as permanent damage to the battery
may result.
VALUE OF
GRAVITY
@80°F
CARRIER A N D HOLD-DOWN
FREEZING
TEM:.
The battery carrier and hold-down should be clean and
free from corrosion before installation.
The carrier should be in a sound mechanical condition
so that it will support the battery securely and keep it level.
To prevent the battery from shaking in its carrier, the
hold-down bolts should be tight. However, the bolts should
not be tightened to the point where the battery case or cover
will be placed under a severe strain. Torque hold down nut
to 26 in. lbs.
CLEANING
The external condition of the battery should be checked
periodically for damage such as cracked cover, case, or vent
plugs or for the presence of dirt and corrosion. The battery
should be kept clean in the area of the terminals. An
accumulation of acid film and dirt may permit current to flow
between the terminals, which will slowly discharge the
battery. For best results when cleaning batteries, wash first
with a soda solution to neutralize any acid present; then flush
with clean water. Care must be taken to keep vent plugs tight
(if so equipped) so that the neutralizing solution does not
enter the cells.
RATINGS
A battery generally has two classifications of ratings: (1)
a 20 hour reserve capacity rating at 80" F., and (2) a cold
rating at
O"
F. which indicates the cranking load capacity (see
Specifications Section at end of 6D for specific battery
ratings). The Ampere-Hour rating formerly found on
batteries was based on the 20 hour rating, and is no longer
used.
SEALED BATTERY
ADVANTAGES
The sealed battery (see Fig. 6D-7) is available on all car
lines for 1977 (see Specifications Section at the end of 6D for
specific applications). The battery grids are made up of a
lead-calcium
alloy
rather
than
lead-antimony. This
compound is less susceptible to gassing, overcharge and self-
discharge, which gives this battery the following advantages:
1. No water addition for the life of the battery. This
improvement makes the sealed battery possible.
2. Overcharge protection. If too much voltage is applied
to the battery, it will not accept as much current as a
conventional battery. In a conventional battery, the excess
voltage will still try to charge the battery, leading to gassing,
which causes liquid loss.
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