You plug into AC at the RV park. It is either 110 30 amp or 220 50 amp. It goes into the converter and you get 110 out of the outlets inside the RV. It is also converted into DC and that runs some of the stuff in the RV plus it charges up your batteries. When you unplug the power line your RV runs on the batteries, which are DC. If you want the TV to work, you need 110 so the converter changes the DC back to AC at 110 volts. If you do not use anything that uses AC then it will not matter but that is unlikely.