tery has been charged or boosted a few minutes prior
to the test, the battery would be slightly warmer.
Refer to Load Test Temperature Chart for proper
loaded voltage reading.
(6) If battery passes load test, it is in good condi-
tion and further tests are not necessary. If it fails
load test, it should be replaced.
BATTERY OPEN CIRCUIT VOLTAGE TEST
An open circuit voltage no load test shows the
state of charge of a battery and whether it is ready
for a load test at 50 percent of the battery’s cold
crank rating. Refer to Battery Load Test. If a battery
has open circuit voltage reading of 12.4 volts or
greater, and will not pass the load test, replace the
battery because it is defective. To test open circuit
voltage, perform the following operation.
(1) Remove both battery cables, negative cable
first. Battery top, cables and posts should be clean. If
green dot is not visible in indicator, charge the bat-
tery. Refer to Battery Charging Procedures.
(2) Connect a Volt/Ammeter/Load tester to the bat-
tery posts (Fig. 6). Rotate the load control knob of the
Carbon pile rheostat to apply a 300 amp load. Apply
this load for 15 seconds to remove the surface charge
from the battery, and return the control knob to off
(Fig. 7).
(3) Allow the battery to stabilize for 2 minutes,
and then verify the open circuit voltage (Fig. 9).
(4) This voltage reading will approximate the state
of charge of the battery. It will not reveal battery
cranking capacity. Refer to Battery Open Circuit
Voltage table.
SERVICE PROCEDURES
BATTERY CHARGING
WARNING: DO NOT CHARGE A BATTERY THAT
HAS EXCESSIVELY LOW ELECTROLYTE LEVEL.
BATTERY MAY SPARK INTERNALLY AND
EXPLODE. EXPLOSIVE GASES FORM OVER THE
BATTERY. DO NOT SMOKE, USE FLAME, OR CRE-
ATE SPARKS NEAR BATTERY. DO NOT ASSIST
BOOST OR CHARGE A FROZEN BATTERY. BAT-
TERY CASING MAY FRACTURE. BATTERY ACID IS
POISON, AND MAY CAUSE SEVERE BURNS. BAT-
TERIES CONTAIN SULFURIC ACID. AVOID CON-
TACT WITH SKIN, EYES, OR CLOTHING. IN THE
EVENT OF CONTACT, FLUSH WITH WATER AND
CALL PHYSICIAN IMMEDIATELY. KEEP OUT OF
REACH OF CHILDREN.
Fig. 8 Load 50% Cold Crank Rating
LOAD TEST TEMPERATURE
MINIMUM
VOLTAGE
TEMPERATURE
CELSIUS FAHRENHEIT
9.6 VOLTS 21° AND
ABOVE
70° AND ABOVE
9.5 VOLTS 16° 60°
9.4 VOLTS 10° 50°
9.3 VOLTS 4° 40°
9.1 VOLTS -1° 30°
8.9 VOLTS -7° 20°
8.7 VOLTS -12° 10°
8.5 VOLTS -18° 0°
Fig. 9 Testing Open Circuit Voltage
BATTERY OPEN CIRCUIT VOLTAGE
OPEN CIRCUIT VOLTS CHARGE PERCENTAGE
11.7 VOLTS OR LESS 0%
12.0 VOLTS 25%
12.2 VOLTS 50%
12.4 VOLTS 75%
12.6 VOLTS OR MORE 100%
LH BATTERY 8A - 7
DIAGNOSIS AND TESTING (Continued)
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