Hi Dan- We LOVE the Jay Flight especially in comparison to the Hideout. The Keystone was a nice unit but was simply too small in the bedroom and bath. And the 3 slides on the Jayco compared to 1 slide on the Hideout... well it's Jed Clampets hillbilly cabin compared to their Beverley Hills mansion
as for the battery question, no there is not a cutoff built in. It should run off your camper battery with no problem. Item #1 for your "tick list" for the dealer to check.
On a different note, I will give you this warning: you need to take the battery out of its case and drill some drain holes in the bottom of the case. The case has two air vents in the lid which allow water into the case but there is no where to go. I was getting ready to take mine out and was surprised to see it standing in water to the top of the battery case. Put a note on the forum and found out it is a common problem.
Hope you enjoy the unit.