Most RV lead-acid batteries self-discharge about ½% a day, maybe more or less, depends on temperature, faster in hot conditions, slower in cold. So after 6 months or so they are pretty much dead. The draw from detectors and LED indicator lights
would discharge a battery
in about a year or ten, except it would already be dead from self-discharge. Think of your household smoke alarm going for a year or two or three on a tiny 9 volt battery
about 1/1000th the size of your rv battery
I don't worry too much about such small loads. On the other hand I keep my stored Scamp
on a time switch controlled battery minder ( one hour per day ) so it's always topped off. What do you folks think?
Btw, batteries have longer service lives at cooler temperatures, so bringing them indoors for the Winter may not be a good idea. Just keep them charged and leave them outside.