We gather some charge data FYI. Check what other CPAP users told:
Phillip Respironics REMstar System One 60: 5 nights (38Hrs) with humidifier/ heater off.
Phillip REMstar System One 50: 6 nights (50Hrs) with humidifier/ heater off.
Resmed S9: 6 nights with humidifier/ heater off.
5 nights at a pressure setting of 11 for a total run time of 33 hours and 37 minutes. (heater and humidifier setting is not told).
ResmedAirsense 10: 6 nights with humidifier/ heater off.
3 nights (20Hrs) with pressure 8.6psi, humidifier on#4, heated hose off.
3.5 nights with pressure 10psi, heater/ humidifier off.
26-28 hours/ 3.5 nights: auto ramp pressure set at 5-12, climate line tube temp OFF, and climate control humidity OFF.
Nearly 4 nights using it 7.5-9 hrs per night with typical pressure settings plus humidity at 3, No heater. Took it down about 25% per night - then ran out about 3 hrs short of a forth full night sleep.
5 nights camping with my ResMed Air 10 (humidifier off/ PSA 11/ 9.5 hours per night).