Bill,

As I pointed out previously the other loads combined with the AC may be pushing the inverter to its limit. I suspect the inverter is overloaded. My refrigerator combined with the current draw from one of my AC units would put the inverter at the limit.

I will not go so far as to suggest the inverter was damaged by the loads, but the inverter was being asked to operate at vitually 100% capacity. Unfortunately I do not know how Royale wired the inverter. On my coach I have the same inverters with separate leads for power input, one for the charging circuit, and one for the pass through power. I have a third set of wires for power back to the isolated inverter circuits in my 120 Volt AC panel. The supply leads are on a dedicated 50 amp circuit breaker. All supply and output leads are #10 wires. My point is that I could probably step my 2500 watt inverters up to 3500 watt without rewiring the coach.

If yours are similarly wired you probably could make a change without pulling new wires. I know my remotes are common to several inverters so I could likely make the inverter change and retain the remotes. This is something you need to investigate to see what your options are.

The two failures you have had are unrelated. One is a failure that prevented you from by-passing any power, and the current failure seems to be a failure only affecting the voltage of the inverter output, but not affecting pass through voltage (if I am reading your post correctly). I think it is just coincidence.

I don't know your skill levels so be careful if you do what follows. If I recall the Royale inverters are accessible. If I had the problems you describe I would access the inverters, and switch out the wires so you are literally reversing the workloads of the two inverters. Then I would run the AC and see if the other inverter pukes. It may mean you just had two coincidental problems, unrelated to inverter loading. I suspect however the inverter is being pushed too hard. If the second inverter also fails you know the answer.