Connecting a CPAP machine to a battery?

kerrlakeRoo wrote:
ktmrfs, my numbers were based off what I got from the company website, it may be high due to them going by the maximums, I dont know.
My pressure has been raised twice by the docs, DW's has half a dozen times so I would assume those pressure settings change power consumption. The bricks also show the watt ratings at 12 volts as 60 for mine and 90 for hers.

If your number is a measured number, and his unit is similar, he could use a group 27 battery and a 50 watt solar panel and would have a surplus. phone, laptop ets charging would all be helped.

I found on both my machines, the mfg ratings are way higher than actual. They usually give a consumption based on power from a 120V line worst case including inrush. since internally almost all are really running of either 12V or 24V there is a conversion loss as well.

I'd bet the 60 and 90W ratings account for the high current needed initially for the humidifier till the water warms up as well, then it drops down to a much lower number.

In any case, the humidifier, if needed, is the biggest power hog. I've found turning it off and filling it with water normally is sufficient.

and yes, I suspect higher pressure has an affect as well.

It would be interesting on your units to hook them to a kilowatt meter and see what it actually draws under various conditions.