[Tiara Open] 2000 3100 no dock AC power, what would draw my house batts down from 12v to 9v?

[Matta0413]

Have you load tested the batteries? How old are they? The only things that should be wired directly to the batteries are the bilge pumps. If your battery switches are off and your batteries are going from 12 to 9 volts over night I would start with checking the batteries. Also, if you have the same Balmar Alternators that I do just running the motors at idle at the dock will not charge your batteries. Need to be above 1000 RPM.