Originally Posted by Wanderer
Apparently there is a Propane Sensor that draws power off the batteries and
will eventually run your batteries down IF you do not remove a cable from your batteries. In my case I lift the battery cover up remove the wingnut and two cables from the negative post. Prior to doing this and the trailer sitting several months it drawed both batteries down enough that there was not power to operate individual lights.
The propane sensor, the smoke detector, and the circuit board for the refrigerator (if you leave the fridge on propane) can all be parasite loads - electrical loads that draw your battery down, even when you think that everything is turned off. These can be eaisily overcome by disconnecting the battery, (they sell inexpensive battery disconnects that do what Wanderer does without creating a potentially dangerous arc), a small trickle/float chargers (requires 120v), or a small solar battery charger (TT can't be stored indoors or in the shade).
Some RV fridges have a fridge switch that is supposed to limit / eliminate condensation around the fridge door. This works well, but it's actually a heating strip that does this, so not only does it "steal" electricity, it requires more propane to overcome the heat being produced.