Charging Procedure
1. Measure the battery voltage:^ Measure the voltage at the battery terminals using a voltmeter.
^ A reading of less than 11 Volts indicates that the charge current is low.
^ The battery will take longer to accept a current higher than 2 milliamps.
2. Set the battery charger on the highest setting.
3. If necessary, disable the polarity protection circuitry:
^ This circuitry, available on most chargers, prevents charging unless the charger leads are properly connected to the battery terminals.
^ A completely discharged battery may not have enough voltage to activate this circuitry, even though the leads are properly connected, implying that the battery will not accept a charge.
^ Most chargers have an override or a bypass function so that the charger will turn on and charge a low voltage battery.
4. The required battery charge time varies according to the voltage capabilities of the battery charger. Replace the battery only if the charge current is not measurable after the following charge times.
^ 16 Volts or more - up to 4 hours
^ 14-15.9 Volts - up to 8 hours
^ Less than 13.9 Volts up to 16 hours
5. Reserve capacity rating:
^ The reserve capacity rating on the battery label is the number of Ampere-hours of charge required in order to produce the green hydrometer dot.
^ For example, if the battery has a reserve capacity rating of 90 (expressed in Ampere-hours), the battery would be recharged as follows:
- 10 Ampere charge x 9 hours = 90 Ampere hours
- 30 Ampere charge x 3 hours = 90 Ampere hours
^ If the green hydrometer dot is not visible after an Ampere-hour charge equal to twice the reserve capacity rating, replace the battery.
6. After charging, load test the battery. Refer to Battery Electrical Drain/Parasitic Load Test. Battery Electrical Drain/Parasitic Load Test