16 Volts is overcharging, and continued use will quickly destroy the battery.
The first guess would be bad wiring to the regulator, or maybe a bad regulator.
Before you do anything, check the water level in the battery - if you've been
running like this its likely down. If everything looks OK, you should check
with a digital meter to verify the voltage. Normally, regulators are set for
14.2 to 14.5 volts, and anything over 14.7 is considered overcharging. If it
really is 16 Volts, don't continue running it.

BTW, at 16 volts you should be able to smell the battery "cooking."





"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?