I just learned all of these lessons about the house battery and the use/store switch after having the RV for over a year. Found the house battery was dead after doing some work on the RV. It stays on shore power all the time but the switch wasn't in the "use" position. I assumed that I could use the battery level indicator to monitor the batteries in every scenario. It showed 100% on the indicator but the battery was dead. I'm guessing that I was seeing the chassis battery?
Apparently, it's best to turn the use switch on before connecting to shore power to ensure that it's in the correct position.
I added this small panel to monitor the house batteries. It's connected right to the house wire at the relay. It also gives us a USB charging port at the table.
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