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ScotchJones · 10-22-2014, 08:05 AM

99 Sig.

I just recently changed out my batteries. I had two deep cycle being used for starter batteries that I switched out for starter batteries.

I recently hit the road on a cross country journey. 6 hours in the trip, I smell sulfur and my coach cuts out...house batteries were boiling over. Called a tech out and he replaced the alternator and 1600 bucks later I was on my way...so I thought. 15 mins later, engine cut out. I managed to jump it and drive Ito a different tech who noticed the battery matenience wire was disconnected. He hooked it up and all was good until that night when I had to put the lights on. The volts start dancing between 10 and 12, lights were dimming, then I hit a hill and it was done. I'm really at a loss here. Any ideas?

450Donn · 10-22-2014, 08:11 AM

It appears the problem started with your changing the chassis batteries. So I guess you need to go back to that point and start searching for what might have gone wrong. One battery mis wired, maybe a bad battery? Who knows but you really do have to go back and start over

twinboat · 10-22-2014, 08:39 AM

It sounds like your Alt. output wire is hooked to your house batteries ( a way to maximize house battery charging ) but your Alt. voltage sense wire is hooked to your start battery. As the start battery runs down the alt senses the low volts and puts out lots of current to the house batteries, overcharging them.

There should be a combining device between the 2 battery banks that may not be working, causing this problem. My M/H has a solenoid under the hood that clunks and connects, when I turn on the key, combining the batteries. I also have a solenoid near the house batteries that clunks when I hit the boost switch, but it does not make a connection. It is bad.

You need a volt meter and a good understanding of 12 volt systems, to check out these things.

Were the deep cycle batteries bad or did you just change them because they were deep cycle? Deep cycle batteries can start engines, if the cranking amps are there.

charliej · 10-22-2014, 08:54 AM

You said you have two batteries, are they connected correctly in series or parallel depending on voltage of the battery?

wa8yxm · 10-22-2014, 10:43 AM

IT sounds to me like you farkled the battery swap out.

There are some rules about taking pictures.. But the sulfur smell was very likely the batteries gassing big time This can happen if you seriously over charge them, This is most likely to happen if you hooked batteries in parallel when they should have been in series.
But if you did that. I'd be surprised if it started.

Alas this is one where I'd need eyes, and meters, on to tell you more.

ScotchJones · 11-07-2014, 04:23 PM

Found the fix. Basically what happened is that the alternator blew, sent a massive surge to the isolator which literally destroyed it. Without the isolator working the alternator continued sending power to the house batteries until they boiled over. Mechanic said I was lucky to break down when I did cause the batteries could have literally blown a hole in the back of my coach. Moral of the story, make sure to maintain the alternator. A $200 replacement could have saved me a $2700 fix. Ouch!

Thanks for all the input, was actually quite fun camping on the side of the road on the Trans Canada Highway in the middle of the boonies.

Papa_Jim · 11-07-2014, 07:07 PM

Glad you found the problem. Strange. Usually when the isolator blows, it stops charging one or both banks of batteries.

Where on the Trans Canada highway did you have to take up residence?

Jim