It is always good to check your boat battery because no one wants to be stuck in the middle of a lake with a dead battery. It is also a good idea to test and keep a reserve battery on your boat at all times. There are a couple of ways to test a boat battery but here are the two most common.
Use a DC Voltmeter
One way is to buy a DC voltmeter to test the battery. First, you will need to disconnect the battery cables. Second, measure the voltage using an accurate DC voltmeter. Last, compare the value with the values below: (Accurate testing depends on the battery not being charged or discharged for 6 hours, preferably 24 hours.)
- 100% 12.73 volts
- 80% 12.50 volts
- 60% 12.24 volts
- 40% 11.96 volts
- 20% 11.66 volts
Load testing is another way to test a boat battery. The device for performing a load test is available at most auto part stores. The amp load for testing should be recorded on the battery by the manufacturer. The load tester puts the battery under stress as if the boat were running and providing an amp reading. If you have a 500CCA battery, the load should test at 250 amps to indicate voltage with load. Reading should be over 11 Volts. Otherwise battery is not able to provide enough power to crank boat. The battery will need charged.