Looking for info on the battery isolator function

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Looking for info on the battery isolator function

Post by TerryB »

I am a new to the BF community having recently purchased an ‘05 30’ RSB and I am looking for input regarding the battery isolator circuit.

I read in the owner manual that the isolator exists to ensure that the engine batteries are not drained by the coach when off grid. However, the documentation is vague and I have a couple of questions:

1. Does the isolator relay operate automatically or is it a manual operation?
2. Where is the relay located on the coach?

During a recent outing I experienced a complete drain down of both battery banks. I was connected to 120v power at the time, but my charger/converter was accidentally turned off. I found and corrected the issue that caused the c/c to be offline, and now my focus is on understanding why I lost both battery banks. Any insight is greatly appreciated.

‘05 30’ RSB
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Re: Looking for info on the battery isolator function

Post by whemme »


The battery isolator relay operates automatically. When you start your coach engine, the relay closes so that the chassis battery and the coach battery(s) are connected in parallel and are charged together by the engine's alternator. When the engine is off, the relay opens and the chassis battery and the coach battery(s) are now isolated from each other. Yours may be stuck in the closed position - that may explain why the chassis battery depleted at the same time as the coach battery(s) when your charger/converter was left shut OFF.

I do not know the physical location of the isolator relay. I would follow the cables from the + terminals on your coach battery(s). One of the cables should lead you to the isolator relay.

You might also want to post this question in the General and Technical Information, Questions, and Responses section on this forum where a lot more people will read it.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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