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Engine Electrical Issues in 2007 RT (isolator?)

4CsonCmpr
Explorer
Explorer
I purchased a 2007 Roadtrek 210 and within 24 hours I was sitting on the side of the road unable to move. I expected issues purchasing a 10 year old RV, especially electrical and battery... but not that soon!
Something was left on that drained the house batteries which in turn put extra strain on the alternator which stopped functioning. I watched the battery light on the dash and the voltmeter just drop as I drove.
The house batteries will only charge from the engine because they had dropped below 10V so plugging in or using the generator to charge was useless (as I watched the Tripp Lite inverter flash the code that says the batteries are too low to charge).
I have the older battery isolator so the alternator auto charges the engine and house batteries. (Not sure if there's a 13V charge that needs to be present on the engine side before charging house batteries begins or if this is only valid for battery separator designs??)
After replacing the engine battery and alternator and turning off all breakers and switches for the house, the in-dash voltmeter was around 12 and the battery warning light was still lit which confused my mechanic and I. We also disconnected the house batteries but that did not make a difference.
We tested the voltage at the battery while running and it was about 12.7.
We tried two different alternators with the same result but they both had built in regulators (brought the first one back to Autozone & it passed their load test so it WAS working!) so we sent the original out to be rebuilt.
We are also charging all the batteries to rule that out.
We think we checked all the fuses.
How can I check the isolator to make sure it is still working correctly?
If the isolator is the cause, is it better to replace the isolator or try to change over to a battery separator?
I can't wait to drive my new RT home so thank you in advance for any help!
-David
2 REPLIES 2

4CsonCmpr
Explorer
Explorer
Thank you Scott!
My mechanic bypassed the isolator and I was able to drive home with 14V on the dash meter and no battery light. There was a connection that was crimped onto a wire in the main harness that was loose and causing the relay to go on and off. He took that out and cleaned the cable.
I'm thinking I might go the same route as you mentioned and put in a battery separator so I can charge either way.

ScottG
Nomad
Nomad
That is exactly how it looked on the volt meter when my diode based isolator died.
I replaced it with a solenoid type relay from NAPA ($20) and never had a problem again.

Here's one on Amazon: linkaroonie
Make sure the one you get is 100% duty cycle.