Second, determine the battery cranking capacity by performing a load test. The battery must be charged before
proceeding with a load test if:
•
Micro 420 tester indicates battery charging is required.
•
The battery open-circuit voltage is less than 12.4 volts.
A battery that will not accept a charge is faulty, and must be replaced. Further testing is not required. A fully-charged
battery must be load tested to determine its cranking capacity. A battery that is fully-charged, but does not pass the
load test, is faulty and must be replaced.
NOTE: Completely discharged batteries may take several hours to accept a charge. Refer to Standard Pro-
cedures for the proper battery charging procedures.
A battery is fully-charged when:
•
Micro 420 tester indicates battery is OK.
•
Open-circuit voltage of the battery is 12.4 volts or greater.
STANDARD PROCEDURE
CONVENTIONAL BATTERY CHARGING
CAUTION: Vehicles equipped with a diesel engine utilize a unique spiral plate battery. This battery has a
maximum charging voltage that must be used in order to restore the battery to its full potential, failure to
use the spiral plate battery charging procedure could result in damage to the battery or personal injury.
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - SPIRAL PLATE BAT-
TERY CHARGING) for the appropriate procedure.
Battery charging can be performed fast or slow, it terms of time. Slow battery charging is the best means of restor-
ing a battery to full potential. Fast battery charging should only be performed when absolutely necessary due to time
restraints. A battery is fully-charged when:
•
Micro 420 tester indicates the battery is OK.
•
Open-circuit voltage of the battery is 12.65 volts or above.
WARNING: Never exceed twenty amperes when charging a cold (-1° c [30° f] or lower) battery. The battery
may arc internally and explode. Personal injury and/or vehicle damage may result.
CAUTION: Always disconnect and isolate the battery negative cable before charging a battery. Do not
exceed sixteen volts while charging a battery. Damage to the vehicle electrical system components may
result.
CAUTION: Battery electrolyte will bubble inside the battery case during normal battery charging. Electrolyte
boiling or being discharged from the battery vents indicates a battery overcharging condition. Immediately
reduce the charging rate or turn off the charger to evaluate the battery condition. Damage to the battery
may result from overcharging.
CAUTION: The battery should not be hot to the touch. If the battery feels hot to the touch, turn off the
charger and let the battery cool before continuing the charging operation. Damage to the battery may result.
Some battery chargers are equipped with polarity-sensing circuitry. This circuitry protects the battery charger and the
battery from being damaged if they are improperly connected. If the battery state-of-charge is too low for the polar-
ity-sensing circuitry to detect, the battery charger will not operate. This makes it appear that the battery will not
accept charging current. See the instructions provided by the manufacturer of the battery charger for details on how
to bypass the polarity-sensing circuitry.
After the battery has been charged to 12.4 volts or greater, perform a load test to determine the battery cranking
capacity. Refer to Standard Procedures for the proper battery load test procedures. If the battery will endure a load
test, return the battery to service. If the battery will not endure a load test, it is faulty and must be replaced.
8F - 10
BATTERY SYSTEM
KJ