You didn't say what kind of Rv you have, how many batteries or what kind. Most new Rvs come with 100W solar panel (if not more) and a solar controller to keep the batteries charged in storage. Rvs in the past 20 years already have a battery cutoff switch which will also help with parasitic drains. All you really need is a 100w set up and a controller to float charge. If you have a motorhome you can also wire it to the chassis battery, but you may need a smart controller in case the batteries are different. A travel trailer with 1 battery is super simple.