[Carl n Susan]

The Level Up and inverter, amongst other 12V devices, need battery power. At 11V or less, the batteries aren't doing it. You are on shore power so the converter should be producing 13.4V or so. That should be charging the batteries but it sounds like it is not. ut the converter can't produce enough amp at 12V to run anything significant (LED lights will work but not high energy draw devices like hydraulics. The inverter duns directly off the batteries and if it say low voltage, the converter in not charging the batteries. Which is what you have determined.

The output of the converter runs through the disconnect battery switch in the convenience center (be sure you can not remove the key as that is the position which allows the 12v to pass), through the two 50 amp self resetting circuit breakers into the batteries.

You need to use a voltage meter and check the power along the way. Be sure to check the converter to ensure it is producing 13.4V or so and the reverse polarity fuses haven't been blown (if the battery display shows full charge I suspect the fuses are OK).

There are only a few places where the flow can be interrupted and a voltage meter will find it easily.

There have been few reports of the left 50 amp circuit breaker failing and not allowing the 12V current to flow.