CPAP Battery Power

I have a Resmed Elite II Cpap and am traveling into an area with NO electricity for 6 nights. Will a deep cycle 12v battery power the unit (no humidifer) that long on a single charge?

It will take a large deep cycle battery to power a CPAP for six nights. If your pressure is set for about 1o cmh2o, your CPAP will draw about one amp. If you sleep seven hours a night, you will need about seven amp hours per night, times six nights is 42 amp hours. You don't want to completely discharge the battery, so figure a 50 amp hour or larger battery.

An Optima Yellow Top D34/78 is 55 Ah, 10"L x 6 7/8"W x 7 13/16"H, weighs 43.5 lbs, and costs $184.37 from amazon.com. You will also need a charger and a proper cable for your CPAP.

I use a 105 ah deep cycle battery, and if it's properly charged it lasts 6 or 7 nights. Even with a deep cycle, you don't want to drop much below 50% so for the 42 ah of load (calculated above by bearded_two) I'd recommend 80 or 85 ah at least, and with a bit of extra just in case (longer sleep, higher pressure or even cold temperatures) you're getting close to 100 ah. I tend to be conservative with my battery (it wasn't cheap) so I'd rather have a bigger capacity than I reckon I'll need, and discharge it less deeply.

ColinP and bearded_two are taking good care of you, Dave.

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