Starter Battery Current Leak

Gary Wells

Seeing about 225 ma leaving the starter battery and I would've expected zero I guess. I'll start chasing it tomorrow but wondered if it's normal, or if not, whare a likely candidate might lie.

Thanks for any insights.

Gary W.
SM 209, Adagio



Almost a quarter amp is a lot, and more than I'd expect as "normal".  This is a lot easier to track down than the similar problem in the 24 volt system...  It has to be either the Onan or the drive engine...  or their 12 volt alternators.

Don't forget accumulated dirt making a part to ground. That would be my bet on this. And if I was putting odds, it would be one of the alternators.

But ground leaks have a way of being infinitely frustrating!

Bill Kinney
Isla Caja de Muertos, PR

Alan Leslie

I see Bill's comment about dirt accumulation providing a path to ground. 
I agree, we had that problem on the Yanmar starter motor...not your problem, but salt infused dirt around the positive terminal of the starter solenoid shorted out the start battery when the key was turned...the panel voltmeter went to zero volts!...the motor wouldn't turn over obviously.
Cleaning all around the terminals cured the problem....which was probably caused by the fact that the raw water pump faces towards the starter motor and there's generally quite a bit of salt water around when the cover plate is removed.
Given that the starter battery is only connected to the alternator and starter on each engine as well as the panel switches...they are the places to look...but my bet would be the alternators and / or starter motors and solenoids.
Good luck
Elyse SM437