electrical problem 02 ss

[wannagobak]

have replaced the battery, but every time we leave the boat overnight the battery drains, have checked that no switches are left on, nothing appears to be running

check that your auto bildge in not stuck on. Often caused by gunk in the pump

[silvtongdvl]

Leave the boat "where" overnite. In the water??? If so it could be your autobilge pump. You might want to check your packing, rubber boots over the exhaust and any thru hull fittings under the water line for leaks.
With that said - if its in your garage - you have a ground short somewhere. The tower light - wiring is the biggest suspect here. I have seen the wiring get nicked with bolts, wiring attached to packup plates for the tower, or just poor grounds. Again the bilge pump switch.
Using a test light or ohm meter that has DC - you might be able to trace the drain.
~S~

[OUI]

It's doubtful that it's your bilge pump, not enogh amps to drain the battery over night. Depending on the age of the boat you may have a voltage regulator problem - sticky contacts will drain the battery in nothing flat. Run you boat and look at the amp meter on the dash if it's jumping around that's probably the cause.

boat is stored on a lift (high and dry), amp meter on dash doesn't jump around