Stray voltage!

[northshoreone]

I'll try to make a long story short...bow thruster was leaking a bit and had it taken out and rebedded three years ago. Found at the time it wasn't bonded to the boat..IE eating zinks! I bonded it at the time...still eating zincs faster than it should. Just pulled the boat again after having it bottom painted, new zincs all around at the time which was two weeks ago. I needed some stabilizer work done..... The zinc up front eaten like crazy in only two weeks!! Measured voltage on the ground was 4.5 volts!!! I had two elect. guys on it for 4.5 hours and are scratching their heads... I turned the breaker off to the thruster charger for now.
The thruster is an add on Westmar 48 volt and a separate line was run from the panel just for it.
Any suggestions for finding the issue is very welcome....I know it wont be easy tracking down stray voltage...
Thanks

 

[davidwigler]

4 volts or more is not just stray current. Try grounding all of your DC battery banks together including the 48 volt.