seen a lot of talk here about the usual Norcold etc 12V fridges. But these almost need a second battery to be useful when parked. I am more interested in one that works off propane as well. Much better IMO for camping since they will run for days off a small propane tank. Seem pretty inexpensive too, about $450 for one in the 35 qt range that I have seen. Can be moved around etc, even come with wheels. I would think this would be a pretty attractive solution. Any experience with these, anybody?