Ernie, the best way to test a batter is with a load tester that uses a
carbon pile, but only shops would have that equipment. Autozone used to test
your battery for free with one, maybe they still do.

The voltmeter test is a good one to use on a battery, without the engine
running. Another poster said that the "voltage will settle down" after a
while....this is called a surface charge, what you get from a battery just
after it has been fully charged. It'll throw the VM test off. To remove the
surface charge, crank the motor for 15-30 seconds.

Another good test for a regular lead-acid battery is the electrolyte test.
It's a glass eye-dropper, you check each cell individually, and that way you
can tell if you have any bad cells. I can't remember the pass/fail,
something like if there are two cells that are bad, then the battery is
trash, or if two adjacent cells are bad....I can't remember. But the
electolyte test will tell you if your battery is bad.

Drew


"Ernie" wrote in message
. ..
Is it normal for the battery gauge to read 16 when the boat is in
operation? The gauge only goes up to 18. The battery will be a year old
next month. Should I be concerned?