Pontiac FIREBIRD 1972 Service Manual page 1296

12-26 1972 PONTIAC SERVICE MANUAL
or indication of poor performance, should be left in ser-
vice. Posts, cable clamps, and top should be cleaned, water
should be added and recharging should be performed, if
required. For dependable and reliable battery service, the
battery should be in at least a 75% state-of-charge.
Batteries designated as good that are suspected of being
questionable because of owner complaint, or age of the
battery, should be further tested by the hydrometer test.
LOAD TEST
Load test equipment is available to test the battery's
capacity under a load. The test is as follows:
Charge battery, if necessary, until all cells are at least
1.200 specific gravity.
ELECTROLYTE
TEMPERATURE
MINIMUM
VOLTAGE*
- -
80°F and higher 9.6
70" 9.6
60" 9.5
50" 9.4
40" 9.3
30" 9.1
20" 8.9
10" 8.7
0" 8.5
*Note: Voltage must not drop below minimum listed
when battery is subJected to proper load for I5 seconds.
Fig. 12-30 Voltage and Temperature Values
If unable to obtain 1.200 specific gravity
@
80" in all
cells, replace the battery.
FULL CHARGE HYDROMETER TEST
If specific gravity is 1.200 or more @ 80" in all cells,
remove vent caps and connect 300 amp load for 15
seconds.
If "smoke" is visible in one or more cells after 300
amp load, replace the battery.
If no "smoke" is visible, place a thermometer in one
cell:
a. Apply specified load as shown in Fig. 12-29.
b. Read voltage at 15 seconds with load connected.
c. Remove load and read electrolyte temperature.
Compare temperature and voltage readings with
those in Fig. 12-29.
If measured voltages are less than Fig. 12-30, replace
battery.
If measured voltages are the same as or greater than
Fig. 12-29, fully charge, clean and return battery to
service.
BATTERY MODEL
-
AMP LOAD
- -
Fig. 12-29 Battery Load Test Values
This test should be used on energizers which test good by
other tests, but which subsequently fail in service.
In order to perform the full charge hydrometer test, the
energizer must first be fully charged by the slow charge
method. This method consists of charging all 12-volt ener-
gizers at a 4-ampere rate until the energizer is fully
charged. A fully charged condition is reached when cells
are gassing freely and no change in specific gravity occurs
over a one-hour period. Due to the low charge rate, a
charge period of 24 hours or more may be required.
With the energizer fully charged, measure the specific
gravity in each cell. If any cell reads less than 1.230,
corrected for temperature, the energizer should be re-
placed.
If the specific gravity readings are between 1.230 and
1.3 10, the energizer is in good condition and may be re-
turned to service.
If any cell reads above 1.3 10, corrected for temperature,
the energizer may be returned to service, but its useful life
has been shortened due to damage caused by the high
specific gravity electrolyte. ~ d j u s t h ~ the specific
to lower levels may not correct the damage that has al-
ready been done.
CHARGING GUIDE FOR TYPICAL PASSENGER
CAR BATTERIES
There are three methods of recharging energizers. They
differ basically in the length of time the energizer is
charged and the rate at which charging current is sup-
plied. One is the slow charge method, the second is the fast
charge method, and the third is the emergency boost
charge method.