Battery Charging

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

Battery Open Circuit Voltage
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 battery load test

Built-In Test Indicator Sight Glass:

- The built in test indicator dot is GREEN.
- The battery cannot be refilled with water. If the fluid level is low, the battery must be replaced.

WARNING: DO NOT CHARGE A BATTERY THAT HAS EXCESSIVELY LOW ELECTROLYTE LEVEL. BATTERY MAY SPARK INTERNALLY AND EXPLODE. EXPLOSIVE GASES FORM OVER THE BATTERY. DO NOT SMOKE, USE FLAME, OR CREATE SPARKS NEAR BATTERY. DO NOT ASSIST BOOST OR CHARGE A FROZEN BATTERY. BATTERY CASING MAY FRACTURE. THE BATTERY CONTAIN SULFURIC ACID WHICH IS POISONOUS, AND MAY CAUSE SEVERE BURNS. AVOID CONTACT WITH SKIN, EYES, OR CLOTHING. IN THE EVENT OF CONTACT FLUSH WITH WATER AND CALL PHYSICIAN IMMEDIATELY. KEEP OUT OF REACH OF CHILDREN.

Disconnect Battery Negative Cable:

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: Charge battery until test indicator appears green. Do not overcharge Battery.

It may be necessary to jiggle the battery or vehicle to bring the green dot (in the test indicator) into view.

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 16 hours
14.0 TO 15.9 Volts = Up to 24 hours
13.9 Volts or Less = Up to 36 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.