Thor Forums - View Single Post - What Charges the House & Chassis Batteries When

Oneilkeys · 03-04-2018, 03:37 PM

Quote:

Originally Posted by Jeff H

Answers:
1. I can't tell if USE mode works as I see no response when Coach is under engine power.
2. Yes, the 100 Amp breaker is closed and voltage is present at the breaker to the Coach batteries.
3. Yes, I'm very sure the power is present as everything works as required under Shore power.

Ref#1 You know if the USE/Store works if, when the coach is unplugged and the engine is not running and the switch is in the USE position, you have 12v power to the coach. If the coach batteries are charged and you have no power to the coach either the USE/Store or the 100 amp breaker in the battery box is open or bad. (As long as the wiring is OK.)
Ref#2, if the 100 amp breaker to the coach batteries is closed and has power to one side but the voltage is not getting to the coach batteries, then that breaker is bad - and that could be your whole problem.

Before you replace the BIRD or Trombetta, I would unplug from shore power and turn on the engine. Then check the voltage on both sides of the Trombetta. Volt meter positive to the engine pole side of the Trombetta and negative to ground. It should read above 13.5v. Now do the same thing to the coach battery side of the Trombetta. If it reads less than the Engine side (12v or so) then the Trombetta is not opening as it should. Either the BiRD or Trombetta are bad or the BIRD is not sensing the voltage of the chassis battery.
If the voltage at the Coach side of the Trombetta is the same as the engine side, then the BIRD/Trombetta are working correctly.

Ref#3.just because everything works in the coach under shore Power does not mean the the USE/Store and/or the 100 amp coach battery breaker are working correctly. The converter/charger is supplying the power to the coach. If on shore power, the voltage on the coach batteries is not above 13.1v then the voltage is not getting from the converter/charger to the batteries thru either the USE/Store or the 100 amp breaker.

So, if you read the same voltage on both sides of the Trombetta with the engine running, the BIRD/Trombetta are good. If that is so and you do not read the same voltage on the coach batteries, either the Use/Store or 100 amp breaker is bad.

Just trying to make sure that you don’t pay $200 for a BIM, when the BIRD/Trombetta are good and either the Use/Store or 100 amp breaker are your real problem.