Time Required, Battery Charged & Testing Information
CHARGING TIME REQUIREDThe time required to charge a battery will vary, depending upon the following factors:
1. Size of the Battery - A completely discharged large heavy-duty battery requires more than twice the recharging as a completely discharged small passenger car battery.
2. Battery Temperature - The charging time required to charge any battery is increased as the temperature goes down. When a fast charger is connected to a cold battery, the current accepted by the battery will remain low. As the battery warms up, it will accept a higher rate of charge.
3. Charger Capacity - A charger that can supply only 5 amps charging current will require a much longer period of charging than one that can deliver a charging current of 30 amps or more. Charging rates of up to 50 amps are generally acceptable PROVIDED the battery does not gas excessively or become over heated.
4. State of Charge - A completely discharged battery will require more than twice as much current input to reach a fully charged state, than a battery that was half discharged when charging began. Because the electrolyte is nearly pure water in a fully discharged battery, it cannot accept current as well as electrolyte. This is the reason the battery will not accept current when the charging cycle first begins. As the battery remains on the charger, the current from the charger causes the electrolytic acid content to rise. This increase in acid content will make the electrolyte a better conductor and the battery accepts a higher charging rate.
Battery chargers vary in the amount of voltage and current that they can supply. Therefore, the time required for the battery to begin accepting measurable current will also vary.
REMEMBER, when you begin to charge a battery, it may be several minutes before charging current is measurable. The charging current will then increase rapidly to normal values provided a good charger is used.
CHARGING A VERY FLAT OR COMPLETELY DISCHARGED BATTERY
Unless this procedure is properly followed, a perfectly good battery may be needlessly replaced.
1. Measure the voltage at the battery terminals with an accurate voltmeter. If it is below 10 volts, the battery will accept current at a very low rate (milliamperes). It could be some time before the charging rate increases. Such low current flow may NOT be detectable on some ammeters.
2. Set the charger to a high setting.
3. Some chargers have a polarity protection feature which prevents charging unless the charger leads are connected to the correct battery terminals. A completely discharged battery may not have enough voltage to activate this circuitry, even though the leads are connected properly. This will make it appear that the battery will not accept a charge. Follow the charger manufacturer's instructions telling how to bypass or override this circuitry so that the charger will turn on and charge a low-voltage battery.
4. Battery chargers vary in the amount of voltage and current they provide. The time required for the battery to accept measurable charger current at various voltages is as follows:
Voltage Hours
16.0 volts or more Up to 4 hours
14.0 to 15.9 volts Up to 8 hours
13.9 volts or less Up to 16 hours
If the charging current is not up to a measurable amount at the end of the above times, the battery should be replaced.
If the charging current is measurable before the end of, or at the end of the above times, the battery is good and charging should be completed in the normal manner.
6. It is recommended that any battery recharged by this procedure be LOAD TESTED prior to returning it to service.
BATTERY TESTING
Load Test
1. Observe the test indicator for presence of the GREEN DOT. If not visible, charge the battery prior to testing.
2. Observing the polarity, connect a voltmeter and a battery load tester with amp-meter across the battery terminals.
3. Apply a 300 amp load for 15 seconds to remove the surface charge from the battery, and then remove the load.
4. Wait at least 15 seconds to let the battery recover, and apply the specified load to the battery.
5. Read the voltage after 15 seconds with the load applied, then remove the load.
6. If the voltage does NOT drop below the minimum voltage listed in the load chart, the battery is good and should be returned to service.
NOTE: THE BATTERY TEMPERATURE MUST BE ESTIMATED BY THE TEMPERATURE THAT THE BATTERY HAS BEEN EXPOSED TO FOR THE FEW HOURS PRIOR TO TESTING.
7. If the battery passes the load test, no further tests are required and it should be returned to service. If it fails the load test, check further to determine whether it should be charged or replaced.
LOAD TEST CHART
Minimum Voltage Temperature F
9.6 70 and above
9.5 60
9.4 50
9.3 40
9.1 30
8.9 20
8.7 10
8.5 0