I find that the auto setting does not switch to battery. It seems to flip between propane and shore power and if it finds neither of them, the check light comes on and you have to turn the fridge off to reset. And if you can't access the fridge when the pup is closed, it makes it hard to switch it. Like hondaman, we got the 277 due to the ability to get to the fridge.
if you have the pup opened up the day before the trip and you have shore power, I would turn the fridge on. Switch it to battery just before you close it up, the converter will work to supply the fridge dc power as long as you are plugged into shore power at your house. Once you hook up the tow vehicle, the power then comes through the battery.
HTT: "EscapeII" 2016 Shamrock 23WS (current)
PUP: "Escape" 2010 Rockwood HW 277 (gone)
TV: "Bruce" 2011 Dodge Durango V8 Hemi Crew
Just us gals (me, Sis and our daughters)
Traveled 19520 miles and 209 nights in 7 years and counting