Hi all. New to the forum. I've been trying to educate myself on the RV electrical system. This thread is great!
Problem: My chassis battery was dead the other day, even though I had it plugged in to shore power; Use switch was ON. (Coach battery was fine)
So today I went to my RV and located the Isolator relay under the hood. Took some voltage readings in an attempt to isolate the problem (no pun intended
). Sorry for the long post but here's everything I measured:
1. Engine OFF. Not Plugged in to shore power. 'Use' switch ON. House battery 13.0V. Truck battery 13.0V. Isolator relay not engaged. This is just my baseline so yes I know this step is unnecessary.
2. Engine OFF. Not Plugged in to shore power. Use switch OFF. House battery 13.2v. Truck battery 13.0v . Isolator relay not engaged.
3. Engine OFF. Plugged in to shore power. Use switch ON. House battery 14.0v. Truck battery 13.0v. Isolator relay not engaged.
4. Engine OFF. Plugged in to shore power. Use switch OFF. House battery 13.0v Truck battery 13.0v. Isolator relay not engaged.
---- Started the engine----
5. Engine Running. Not plugged in to shore power. Use switch ON. House battery 15.0v. Truck battery 15.0v. Isolator relay engaged (energized and equal readings on both large posts).
6. Engine Running. Not plugged in to shore power. Use switch OFF. House battery 15.0 . Truck battery 15.0V. Isolator relay engaged
7. Engine Running. Plugged in to shore power. Use switch ON. House battery 15.0V. Truck battery 15.0V. Isolator relay engaged
8. Engine Running. Plugged in to shore power. Use switch OFF. House battery 15.0V. Truck battery 15.0V. Isolator relay engaged
-----
Since the isolator relay actually does function and allows charging from Chassis --> Coach (but not the other direction) my guess is this is a bad BIRD?
Thanks!
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2014 Thor Four Winds 32'
Thor Forums
