Open-Circuit Voltage Battery Test
For accurate voltage readings, batteries must remain idle (no charging, no discharging) for at least 8 hours, preferably 24 hrs.
- Disconnect all loads from the
- Test specific gravity if possible. The OCV of the tested cell will be the specific gravity reading + .84
- Example 1.22 s.g. + .84 = 2.06V
- Measure the voltage using a DC voltmeter.
- Check the state of charge with the Table below.
- Charge the battery if it registers 0% to 75 % charged.
After a charge, if the battery registers below the Temperature Compensated values illustrated in “How can you tell if a battery is fully charged” or “How can I measure my battery's State of Charge,” the following conditions may exist:
- The battery was left in a state of discharge for too long.
- The battery has a bad cell.
Batteries in these conditions should be taken to a specialist for further evaluation or retired from service.