The amp rating describes your RV's shore-power connection, and it is easy to read it as a target the battery has to hit. It is not — it is a ceiling. On a battery, the station's output is what limits you.
30 amp RV
One 120V leg, about 3,600W
Usually one air conditioner. A 3,000–3,600W station covers most of what the RV could draw from the pedestal anyway, so a single AC plus the fridge and lights is realistic — for as long as the battery lasts.
50 amp RV
Two 120V legs, about 6,000W each
Up to roughly 12,000W in total, usually split across two ACs and the rest of the coach. No portable station in our database comes close, so on battery plan on running one AC, not two.
Connecting a 50 amp RV to a station. The common route is a 50-to-30 amp adapter into a station's RV-style outlet, which limits the coach to what that one connection and the station can supply. That is fine as long as you manage loads — one AC at a time, and no electric water heater or microwave while it runs.
240V split-phase stations. Some home-backup units in our list offer 120/240V output. Whether that can feed a 50 amp RV inlet directly depends on the outlet type and the manufacturer's guidance. Confirm it in the manual; do not improvise an adapter for a split-phase connection.