The Phillips System One operates on 12 volts. That is absolutely the way to go. Never get a CPAP for RV use that requires AC power unless you never plan on camping without a hook up. As the data shows and as is also shown my the CPAP manual, 110v operation will use much more power than 12v operation. In addition an inverter would be needed to supply 110 from batteries. Inverters waste power in the form of heat. Many even waste more heat operating a fan to cool the inverter. Avoid the use of an inverter whenever possible.
Humidifiers relay on a heater next to the water tank. Depending on the device and setting they can use much more power than the CPAP itself. There is another potential drain that is even bigger. Many CPAPs now have a heated tube from the unit to the mask. Those are huge, huge power hogs.
