My brother in-law has a 5500 onan genni that is a 50 amp. Is it possible to wire it in to an older 30 amp 4k onan powered rv? I'm not an electrical guru. I would think higher amp breakers and maybe a bigger/different convertor? Has any one done this? Thoughts, suggestions?

If I recall correctly the Onan 5500 has a 2 circuit output, 1- 30, and one 20 amp circuit with seperate circuit breakers, many manufacturers (even WW) don't even connect the 2nd circuit unless there is a second AC unit. You could install it if it fits but you must put in a second circuit seperate from your existing panel or AC unit to take advantage of the extra capacity.
uses more gas, more noise, definately more weight.

Not sure the point of putting a 50 amp gen in a 30 amp rig. Unless you want to run a welder, microwave, A/C, all at the same time.

Not sure on this one, but is a 50 amp gen 220? Is a 30 amp gen 110?

Usually when you plug a 30 amp rig into an RV space the 30 amp plug in is only 110 and the 50 amp plug in is 220 is it the same for Generators?

It's actually for a customer of my brother inlaw. Just tried to keep the post short. The guy bought the 5500 out of a repo without knowledge of 50 or 30 amp units.

I'm thinking amp draw and wire size in the coach may be an issue.