If your TT has a Smoke Detector, Propane / Carbon Monoxide alarm, 12V (or Propane) Refrigerator setting, Radio / Entertainment System, interior lights, Break-Away Switch, Propane Heater, Water Pump.....etc....these are 12V powered systems....and.... you are at risk of a) accidentally leaving the device on - or - b) continual drain while 12V source power is available / connected....
By law...some of these devices MUST be ON when power / voltage is present.
Disconnect your battery (and turn off your propane source) when your vehicle is stored / not in use.....