Travel CPAP that will run on 12V - 2016 update? ;-)

[Shorty]

I use a Devilbiss Intellipap 2 with humidifier when travelling, runs on native 12v and I run it all night every night whilst asleep, no mains or inverter power just on the 12v house battery in our small motorhome.
I also have a Respironics system one D560 (think that's the model) with humidifier and it also runs direct on 12v but seems to use more power than the Devilbiss plus it has a much bigger footprint.

[Sleepster]

I wonder what compelling reason Resmed Engineers had for designing their units to run on 24V rather that 12v ....

I've never verified this, but I was told that ResMed's blower motors are heavier duty.

I have taken apart both a ResMed S9 and a Philips Respironics System One. The ResMed motor is indeed heftier.