Battery Charging

Before recharging a discharged battery, inspect and service the following conditions, if they exist:

1. Loose generator drive belt.
2. Pinched or grounded generator/generator regulator wiring harness.
3. Loose harness connections at the Generator (GEN) and/or Voltage Regulator (VR).
4. Loose or corroded connections at battery and/or engine ground.
5. Excessive battery drain due to:
a. Hood, luggage compartment, glove compartment and courtesy lamps remaining energized (for example damaged switch or glove compartment left open).
b. Luggage compartment solenoid continuously energized on vehicles equipped with electronic door lock control system.

Maintenance-Free Batteries

WARNING: WEAR SAFETY GLASSES. BATTERY CHARGING CAN BE DANGEROUS. WHILE BEING CHARGED,THE BATTERY PRODUCES A POTENTIALLY EXPLOSIVE MIXTURE OF HYDROGEN AND OXYGEN GASSES. KEEP SPARKS, FLAMES AND LIGHTED CIGARETTES AWAY FROM BATTERIES. REMEMBER, IN CASE OF ACID CONTACT WITH SKIN, EYES OR CLOTHING, FLUSH IMMEDIATELY WITH LARGE AMOUNTS OF WATER. GET MEDICAL ATTENTION.

Cold batteries will not readily accept a charge. Therefore, batteries should be allowed to warm up to approximately 5°C (41°F) before charging. This may require four to eight hours at room temperature depending on the initial temperature and battery size.

A battery which has been completely discharged may be slow to accept a charge initially, and in some cases may not accept a charge at the normal charger setting. When batteries are in this condition, charging can be started by use of the dead battery switch on chargers so equipped.

After releasing dead battery switch and with charger still on, measure battery voltage. If it shows 12 volts or higher, the battery is accepting a charge and is capable of being recharged. However, it may require up to two hours of charging with batteries colder than 5°C (41°F) before the charge rate is high enough to show on the charger ammeter. It has been found that all non-damaged batteries can be charged by this procedure. If a battery cannot be charged by this procedure, it should be replaced.

If the battery has failed, or is low in charge, it may be necessary to refer to Diagnosis.

Completely discharged batteries which have been discharged for a prolonged period of time (over one month) or which have an open circuit voltage of less than 2 volts, may show no indication of accepting a charge even when the dead battery switch is used. The initial charge rate accepted by batteries in this condition is so low that the ammeter on some chargers will not show any indication of charge for up to 10 minutes.

A rapid recharge procedure has been developed for recharging batteries that have passed the Load Test and only need a recharge. This can be due to either in-service no-start battery failures (vehicle will not crank due to low battery state of charge), or battery discharged in vehicle due to keyoff loads. Refer to Load Test procedure. [1][2]Battery Load Test

The battery can be rapidly recharged by using either of the following methods:

NOTE: If excessive gassing or electrolyte spewing occurs during the charge, discontinue charging. The battery has reached serviceable charge. If the battery will not accept at least 5 A after 20 minutes of charging, replace the battery.
- Perform a 2-hour charge using 20 A constant current (manual setting on charger).
- Perform a 2-hour charge using a constant potential (automatic setting on charger).