Forum Discussion

CVD's avatar
CVD
Explorer
Jan 11, 2017

24 Volt CPAP

I just picked up a new 24V CPAP machine (ResMed AirSense 10). This replaced a 20 yr old machine that I ran off AC at home and 12V DC in the RV (used the 12v TV outlet in the bedroom). Two questions:

1) Short of buying the $85- DC converter from the manufacturer (link below), is there an easy/inexpensive way to get 24V to this machine from a 12V outlet?

http://www.cpap.com/productpage/resmed-dc-converter-airsense-aircurve-10-machines.html

2) I have a cheap 400w inverter ($50 from Costco) that I use to charge misc devices. It certainly isn’t “pure sine wave”. Is a CPAP machine something that will be harmed by a non pure wave pattern? I used to think not, but this new CPAP machine is web enabled, transmitting info to my doctor. Much more sophisticated than my prior machine.
  • horton333's avatar
    horton333
    Explorer
    Jan 11, 2017
    My wife's CPAP machine worked fine on a cheap MSW unit, as will most noninductive loads. It will use more power than PSW, the wall wart ran noticeably warmer before I wired in a larger PSW unit for general usage and that is consistent with my laptop when I used to bring it.
  • Shadow_Catcher's avatar
    Shadow_Catcher
    Explorer
    Jan 12, 2017
    Looks like you will need 90W and there are DC DC boost converters that include a volt and amp meters. They are available through Amazon.
    I use the converters for other purposes and carry two (I had one fail).
  • ktmrfs's avatar
    ktmrfs
    Explorer II
    Jan 12, 2017
    here is what you want.

    http://www.batterypowersolutions.net/product/resmed-24v-power-converter

    extremely high quality stuff. available on amazon and other sources. This is what I use with my resmed airsense 10. WAY WAY better than running an inverter and it's additional power loss.
  • Stefonius's avatar
    Stefonius
    Explorer
    Jan 12, 2017
    I went around and around with the same choices for my S9. In the end, the best solution turned out to be buying the $85 DC-to-DC converter from ResMed. I added a 12v outlet in the bedroom of the RV that is direct-wired to the battery and now I can boondock in peace and happiness.
  • horton333's avatar
    horton333
    Explorer
    Jan 12, 2017
    Why so many suggestions to buy something when he has what he needs already?
  • 2oldman's avatar
    2oldman
    Explorer II
    Jan 12, 2017
    horton333 wrote:
    Why so many suggestions to buy something when he has what he needs already?
    Apparently he doesn't want to part with $85. Is that what you meant?
  • horton333's avatar
    horton333
    Explorer
    Jan 12, 2017
    2oldman wrote:
    Apparently he doesn't want to part with $85. Is that what you meant?

    $85 for the fancy DC to DC or a couple of dollars for the cheaper ones it's one more thing to buy and have in the trailer IMHO. Just wonderin' - no biggie but I would use what I already had and here that is the MSW unit.
  • CVD's avatar
    CVD
    Explorer
    Jan 12, 2017
    OP here - Yes (to Horton333), I already have something that will work (400w inverter, plugged into bedroom 12V outlet). As others have said, that is inefficient (converting 12v DC to 120v AC to 24V DC), but it should work. I was concerned about the lack of PSW inverter hurting the CPAP - doesn't sound like that will be an issue.

    Another Yes (to 2oldman), I'm reluctant to part with the $85 unnecessarily. I'll try the inverter for a couple days next week; might end up getting that DC converter.

    Thanks to all for the feedback,
  • horton333's avatar
    horton333
    Explorer
    Jan 12, 2017
    BTW CVD, I just checked - should have earlier doh! - my wife's machine is the same unit you mention. ResMed AirSense 10 (also says Elite below the AirSense 10 label).

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