One time they made me stop and shut it off while traveling thru the Chesapeake Bay Tunnel but the next time down that way they didn't. I ran into a fellow this past weekend camping that didnt have a propane option on his refer, it was a house unit whirlpool inside of a Forest River Cross Country Edition fiver, about 40 foot long with 4 slides. It runs off his 4 dc batteries up to two days before he has to fire his generator up to charge the batteries back up otherwise he is on electric all the time with a unit that size. I had an old truck camper once that was 3 way with a DC option. Those units are expensive these days so you rarely see them.