My RV has roof-top air conditioning units. The generator will run 2 units. I would like to convert the RV to a mini-split system with 2 air handlers. They require 220V, and draw 25 amps; however my Onan generator is 120V.

I can convert from 120V to 220V with a transformer, right? What is the proper transformer spec.?

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    For sale - 110V generator. Wanted to buy - 220V generator. – Ecnerwal Apr 27 '19 at 12:52

You almost certainly don't want to do that. You'd need a transformer that can handle over five kilowatts, and will probably be too big to hide on your RV (I've seen similar ones for over a thousand dollars, almost two hundred pounds, and that are a 20" cube.)

But, if you change your generator from a 110VAC to a 220VAC, you'll have to figure out another way to power your local 120VAC appliances. Maybe you'll need a 220VAC to 110VAC transformer, but the power requirements for that would be far lower than for what you're asking.

If these min-splits are meant for RV use in the US, then the manufacturer will have dealt with exactly this problem again and again and again. Call them and find out what they suggest.

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  • North American 240VAC generators are virtually all set up to provide 120VAC, same as the North American Grid. (120/240 is more accurate for the actual grid supply here than 110/220) – Ecnerwal Apr 27 '19 at 18:09

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