Originally Posted by Bond
My understanding is if anything happens to be left on it will run the batteries down.
True, but usually when one is done camping for the weekend, the heat is turned off, things are packed up, and there is a drive home, when the unit goes into "sleep" mode, that's when you "turn off" your battery. The furnace fan usually only runs for about a minute or so, so that is some fast packing, unless you forgot to turn off the furnace and just killed the battery. Either way, things happen and you've learned a lesson. Now you can be an educator to those who don't know any better!