Running CPAP While Boondocking

[Super Thirty]

Thanks for the info. We are planning a trip and we are expecting to have to boondock more often. We have not boondocked since DW got the CPAP machine so we are going to try it out a few times before leaving on our trip. I was wanting to accommodate the use of her CPAP.

[harryn]

So in rough numbers, it pulls about 100 watts, which is pretty typical of a CPAP with humidity. This of course can be optimized but it is still going to be closer to 100 watts than 25.

10 hours x 100 watts = 1 000 watt - hrs.

In 12 volt terms, and assuming that you are using AGM or flooded batteries, with 50% usable capacity:

1000 watt -hrs / 12 volts = about 100 amp hours of 12 volt battery capacity.

Since you can only use 50%, then

100 amp-hrs x 2 = 200 amp-hrs of 12 volt capacity EVERY night that needs to be available and recharged from "something".

Assuming that you need some power for other things, then this would "indicate" a need for around 400 amp-hrs of AGM or equivalent battery capacity.

[harryn]

Assuming that your 400 amp-hr pack is adequate for your more general needs, then a solar system with roughly 400 watt name plate capacity would be about right,

How close is your RV to having 400 amp-hrs of battery capacity and 400 watts of solar?

If you have 1/2 of that, she is going to be miserable.

[Super Thirty]

I’m not sure off the top of my head. I’m on the road and would have to look to be sure. I ordered the dc converter for her machine from CPAP. Once it arrives I’m going to test it at home before travelling. If I need more battery capacity it’s easier to deal with here than on the road.

[Super Thirty]

Just thought I’d update this post. I purchased a DC adapter for DW CPAP and tested it out. Was just the ticket. Thanks to all who shared their knowledge.

[Super Thirty]

Just a further note. We got more information from this forum than we got from the place where she got her machine.