Long term storage Solar Setup question

I am planning to be away for 6+ months from my rv... what do most ppl do with their solar setup? do you guys just keep it powered on to charge your lipo4 batteries or shut off everything? I heard if u keep your batteries constantly topped up it will lose charge and so you should turn on something at least like a interent router or something to have your batteries power something while solar is on? I have 3x 300ah lith batteries in series with 400watts solar