Bad Battery Cables?

[Don't Trip]

So I have had this electrical ghost for almost exactly 1 year. Initial problem was that the my port engine died on me 70 miles out one day, boat only has about 60 hours on it. After 9 hour ride home in the slop, I take it to the mechanic, and nothing is wrong and he can't find a thing. Boat runs excellent for 10 months, quite few trips. About a month ago the problem reared it's head again, take it back to the mechanic and after extensive testing and starting, nothing wrong. Finally on weds. boat's port motor dies at the bait barge at 4 in the morning. Waiting for my mechanic to get to work, we dive into it first thing. Symptoms are there, so we end up finding that the port's motor negative battery cable is burnt on the underside at the block. Definite sign of arcing. My mechenic chalked it up to bad cable from the factory? Maybe the paint where the wire mounts on the block, he couldn't really put a finger on why, but that it was definitely a short which we reapired by putting on a new cable.
Has anyone heard of something like this or had it happen to them?
What was the reason behind it?

Dave

 

[DaleH]

Has anyone heard of something like this or had it happen to them?

What was the reason behind it?

Dave:

Sounds to me like sometime, somewhere, somebody 'may' have put the leads onto the battery backwards and possibly not in the right order, and then coupled with a battery switch ... and yes, I can see it possible to occur.

With a common ground between the motors (lead from one to the other) I can easily see this happening. Someone goes to remove one battery, removes that lead, now the other battery isn't grounded per se to the rig ...

That is why on my boat, each battery is sepately grounded to a common power bar that connects to the OB's negative lead. All (-) leads to the helm also originate or terminate here.

Easy for me to say 'now', but ANYTIME one gets a flunky electrical thing like that, I have learned to grab a voltmeter and perform resistance checks. You also might want to check the contacts on your battery switch. I have had a battery switch fail on me and it looked primo for all intents and purposes.