If powering a microwave, the inverter must be fairly large; like at least 1,500-Watt unit. In any case, is it really that different than plugging a motorhome into a 1,000 Watt inverter-generator to power TVs and the like? It’s a little different, but requires turning off most things in RV like A/C, water heater electric, refrigerator electric, etc. Biggest difference I see is having to turn off converter; but in some cases the converter has to be turned off also with small generators to keep from overloading the generator.
I have a small portable inverter and have plugged the 30-Amp cord to it with an adaptor for testing purposes. From electrical standpoint it wasn’t much different than when I connect to my portable generator — except generator can handle larger loads.
For what it’s worth, I would also turn off the motorhome’s generator to be safe, particularly if equipped with automatic start.
As others have stated, I would wire in a permanent installation for repeated use. For a one-time event, I’d try it. Keep in mind batteries will likely run down faster than expected.
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