Camping with a CPAP (xpost to CPAP)

I've been reading up on this a bit, and I'm trying to come up with a solution. I like to tent camp in the middle of nowhere, with no electricity. I'd like to take my cpap with me. I understand I won't be able to use the humidifier or heated hose with this setup. But I'm basically thinking I could get a deep cycle battery. I already have a trolling motor power box that has a cigarette lighter outlet on it. I also have the cigarette lighter cord for my dreamstation. I realize this will be heavy, but I never set up far from the truck.

My question is has anyone done this? My concern is the battery, and discharging gas. A tent seems far from airtight, but is there still a danger? I think I could run the cord outside the tent if need be. Any other ideas?