What is pulling down the battery?

We had same problem in past. The guys here are correct. Lots of little demons in modern RVs. You can install toggle switches on things like the radio. A friend even put one on the CM detector which you could have turned on when you are in camper and turn off when not there. New refrigerators have these little fans inside there and they also eat power. Our advice is go with 2-6volt batteries of a real good brand and get a solar panel. That is what we are going to do on our new camper. Also, if you are using Interstate battery, get a better brand. We also found that if you let your battery run down too far or dead, it seems to "damage" it and after that won't hold a charge. Our last 12v battery (Interstate) the shop where camper was awaiting repairs well they left switch on and it went dead, then we went on a trip and accidentally let it go dead and after that would not hold a charge.