Battery Charging

A battery is considered fully charged when it will meet all the following requirements.

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 %

- It has an open circuit voltage charge of at least 12.4 volts (refer to Battery Open Circuit Voltage table).
- It passes the 15 second load test, refer to Battery Load Test Temperatures Table.

WARNING:
- DO NOT ASSIST BOOST OR CHARGE A FROZEN BATTERY.
- EXPLOSIVE GASES FORM OVER THE BATTERY, DO NOT SMOKE, USE FLAME, OR CREATE SPARKS NEAR BATTERY.

CAUTION: Disconnect the battery NEGATIVE cable first, before charging battery to avoid damage to electrical systems. Do not exceed 16.0 volts while charging battery. Refer to the instructions supplied with charging equipment

Battery electrolyte will bubble inside of battery case while being charged properly. If the electrolyte boils violently, or is discharged from the vent holes while charging, immediately reduce charging rate or turn off charger. Evaluate battery condition. Battery damage may occur if charging is excessive.

Some battery chargers are equipped with polarity sensing devices to protect the charger or battery from being damaged if improperly connected. If the battery state of charge is too low for the polarity sensor to detect, the sensor must be bypassed for charger to operate. Refer to operating instructions provided with battery charger being used.

CAUTION: Do not overcharge Battery. Refer to Battery Charging Rate table.

After the battery has been charged to 12.4 volts or greater, perform a load test to determine cranking capacity Refer to Battery Load Test. If the battery will endure a load test, return the battery to use. If battery will not endure a load test, it must be replaced. Properly clean and inspect battery hold downs, tray, terminals, cables, posts, and top before completing service.

Charging Completely Discharged Battery
The following procedure should be used to recharge a completely discharged battery Unless procedure is properly followed, a good battery may be needlessly replaced. Refer to Battery Charging Rate table for correct charge times.

BATTERY CHARGING RATE
Voltage = Hours
16.0 Volts Maximum = Up to 4 hours
14.0 TO 15.9 Volts = Up to 8 hours
13.9 Volts or Less = Up to 16 hour

Voltmeter Accurate to 1/10 Volt Connected - Typical:

1. Measure the voltage at remote cable terminals with a voltmeter accurate to 1/10 volt. If below 10 volts, charge current will be low, and it could take some time before it accepts a current in excess of a few milliamperes. Such low current may not be detectable on amp meters built into many chargers.
2. Connect charger leads to the remote cables. Some chargers feature polarity protection circuitry that prevents operation unless charger is connected to battery posts correctly. A completely discharged battery may not have enough voltage to activate this circuitry. This may happen even though the leads are connected properly.
3. Battery chargers vary in the amount of voltage and current they provide. For the time required for the battery to accept measurable charger current at various voltages, refer to Battery Charging Rate table. If charge current is still not measurable after charging times, the battery should be replaced. If charge current is measurable during charging time, the battery may be good, and charging should be completed in the normal manner.