Battery Charging

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

1. Loose drive belt.
2. Pinched or grounded generator/voltage regulator wiring harness.
3. Loose harness connections at the generator (GEN).
4. Loose or corroded connections at battery, starter relay and / or engine ground.
5. Excessive battery drain due to hood, glove compartment and courtesy lamps remaining energized (damaged or misadjusted switch, glove compartment left open, etc).

Cold battery will not readily accept a charge. Therefore, battery should be allowed to warm up to approximately 5°C (40°F) before charging. This may require 4 to 8 hours at room temperature depending on the initial temperature.

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 normal charger setting. When batteries are in this condition, charging can be started by using the dead battery switch in chargers so equipped

Completely discharged batteries that have been discharged for a long period of time (over one month) or which have a voltage of less than two 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 slow that the ammeter on some chargers will not show any indication of charge for up to 10 minutes.

Follow the charger manufacturer's instructions for use of the dead battery switch. If the dead battery switch is the spring loaded type, it should be held on the ON position for up to three minutes. After releasing the dead battery switch, 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 before the charge rate is high enough to show on the charger ammeter.

All non-damaged batteries can be charged by this procedure. If a battery cannot be changed by this procedure it should be replaced.

Once it has been determined that the battery is accepting a charge, it can be charged by one of two methods.

^ The first method uses the AUTOMATIC setting on chargers so equipped. This setting maintains the charging rate within safe limits by adjusting voltage and current to prevent excessive gassing and spewing of electrolyte. Approximately 2 to 4 hours will be required to charge a completely discharged battery to a serviceable state. If a full state of charge is desired, the charge can be completed by a low current rate of 3 to 5 amps for several additional hours.
^ The second method uses the MANUAL or constant current setting on the charger. Initially set the charging rate for 30 to 40 amps and maintain this setting for approximately 30 minutes or as long as there is no excessive gassing and electrolyte spewing. If gassing results, the charge rate must be reduced to a level where gassing will stop. Excessive gassing will result in non-replaceable loss of electrolyte and shortened battery life.

The total charge required will vary with battery size and its initial state of charge. In general, to bring a discharged battery to a serviceable state of charge, current-time input should equal the battery amp-hour capacity. For example, a 48 ampere-hour battery will require 15 amps of charge for 3.2 hours or 10 amps of charge for 4.8 hours.

Again, if a full state of charge is desired, the charge can be completed by a low constant current of 3 to 5 amps for several hours.

Batteries
Read the battery open circuit terminal voltage using Rotunda 73 Digital Multimeter 105-R0051 or equivalent. If the open circuit voltage of the battery is below 12.4 volts, quick charge of the battery for two hours and recheck the voltage. If the open circuit voltage is still below 12.4 volts, replace the battery.