How old is the RV you just purchased?
How big is the "house-battery" bank? One, or more batteries? Group 24, or larger?
To use the inverter both it and the "House-battery" disconnect switch must be "on" (note! monitor panel will not function without batteries connected and charged). Exception is that plugging into shore-power will allow the converter/charger to power both 120v,ac, items and outlets along with the 12v,dc, circuit (panel will work). BUT! The batteries are not connected yet so no charging taking place.
The batteries may not have been charged recently. If they have been allowed to discharge too many times they may no longer hold a charge and will need replacement.
