I have cruised with several different machines. The one I like best is the Everest. It is very small and you can purchase an integrated lithium battery. It provides for me, at 12psi, about 10 hours of running per charge. If you use the integrated heated humidifier only about 5 hours. You can buy a 12 volt power supply and charge it from the house batteries during the day. Total usage nightly is about 5AMP hours. I've had it for 4 years and very pleased with the unit and use it as my every day device. I purchased it from cpap.com, you must have a prescription, and was very happy with their service.