I have been dry camping with a CPAP since I was diagnosed 7 years ago. All the methods described above should work. I installed two 12V Deep Cycle batteries under the bed that are dedicated to powering my ResMed unit with the humidifier. If necessary, I will run my Honda 2K generator during the day to recharge those as well as the RV batteries. The dedicated batteries are hooked up to a battery charger/maintainer that will have those batteries fully charged and ready for my next trip. There should be no reason for someone to run a generator during quiet hours/overnight to power their CPAP. Happy Dry Camping to you!