It runs on AC, Propane and DC but uses a good amount of power on DC. I tried running it on DC one sunny afternoon in western Oregon while driving East thinking the 160 Watt solar panel could handle it. It couldn't, by the time I stopped my batteries were at 66% so I switched it back to propane. I also had frozen gel packs in the freezer and refrigerator box. Now, when it is running on propane I switch off the Auto mode out of fear that if the propane stops working it will drain my battery trying to keep cool.
Don't know about the Americana (DM2663), but the older one in my 2014 will not automagically switch to battery, only back and forth between AC and LP. Battery is a manual swap, which is good. Might try it under controlled conditions to verify yours.