Battery Open-Circuit Voltage Test

A battery open-circuit voltage (no load) test will show the state of charge of a battery. This test can be used in place of the hydrometer test. Before proceeding with this test, make sure the battery is completely charged.

1. Before measuring the open-circuit voltage, the surface charge must be removed from the battery. Turn on the headlights for fifteen seconds, then allow up to five minutes for the battery voltage to stabilize.
2. Disconnect and isolate both battery cables, negative cable first.
3. Using a DVOM (Digital Voltage and Ohm Meter) connected to the battery post, measure the open-circuit voltage. Refer to the Open-Circuit Voltage table. This voltage will indicate the battery state-of-charge, but will not reveal its cranking capacity. If the open-circuit voltage reading is 12.4V or greater, perform the load test.