CPAP battery usage

Discussion in 'Boondocking' started by Gafrus, Sep 10, 2019.

  1. Gafrus

    Gafrus New Member

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    Does anybody know how much power a CPAP machine uses? My dad will be coming with for a 2 night trip and I'm wondering how much of a difference it will make in battery usage.
     
  2. GreyFox

    GreyFox Well-Known Member

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    Considerable - but how much it affects your battery reserve depends on the specific model of CPAP he has, whether he needs to run the humidifier or not, how many batteries you have, the type & size of batteries you have, and details about devices you want to also run yourself, none of which you've told us.
     
  3. Gafrus

    Gafrus New Member

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    Hmm, I don't know details of the CPAP but describing it as "considerable" is really what I was wondering. I didn't know there was a humidifier option and it sounds like that will go through a battery fast. I plan on using the trolling motor batteries out of my boat and have up to 3 of them. I think I'll just bring one with an inverter dedicated for his CPAP. Thanks!
     
  4. Bradley E Dixon

    Bradley E Dixon New Member

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    They use a "significant" amt of power to run. By that I mean high amp/hr draw. If you have a INTERSTATE DEEP CYCLE battery this is what they are rated for:

    interstate amp hr.JPG


    Most CPAP machines, depending on pressure settings, are between 30-60 Watts. That's like a light bulb. 30 Watts translates to 2.75 amps from the battery through an inverter. 60 Watts becomes a 5.5 amp draw


    Since both my wife & I need/use one you I guestimate that both our machines are pulling somewheres around 11 amps at peak for about 6-8hrs of sleep. That doesn't include any other 12v power draw(s) - fans/furnace/light etc.

    As you can see by the chart - more amps/per hr - battery sustainable power outputs drops.

    We just run our generator thru the night

    I'd also watch for humidity levels in the camper. CPAPs don't work particularly well in a high moisture environment. We found we had to run the A/C on low or dual 12v fans (the ones that attach to the overhead bed arm(s)) with some flaps open.
    The machines will literally "drown" out and make the wearer feel like he/she is under water (not a nice feeling to wake up to) if the interior humidity gets high

    My 2cents..
     
    Last edited: Sep 10, 2019
  5. Gafrus

    Gafrus New Member

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    Wow, thanks for all the info Bradley! I don't have a generator but I do have up to three SRM27's available. Maybe I'll just bring all 3 this time until I see what happens.
     
  6. BikeNFish

    BikeNFish Well-Known Member

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    To run a CPAP all night, I HIGHLY recommend that you use a minimum Group 27 battery and use a battery charger to recharge it. The humidifier must be turned off.

    Both my DW and I have CPAPs. I use two Group 27 batteries hook up in parallel and a 800 watt inverter to run both CPAP's for 8 hours. It takes a minimum of three hours to recharge the batteries. I use a generator to recharge if there is no shore power.
     
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  7. SteveP

    SteveP Well-Known Member

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    It's really hard to say without knowing more details about the cpap machine, whether or not you can turn off the heater/hmidifier, if Dad would even be able to sleep with them off. If your SRM-27s are in good shape one would probably work for two nights, but since more are available why not use them. I don't think you need all 3, one for each night would probably be more than sufficient.

    If this is going to be more than a one time thing you might try running on a single battery both nights to get a better idea of how far you can stretch it.
     
  8. BikeNFish

    BikeNFish Well-Known Member

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    HERE is another thread that has a lot of information about running a CPAP in the pup.

    And did you know that the outlets do NOT work on battery power? Only on shore power.
     
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  9. dbhost

    dbhost Well-Known Member

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    The answer is, it depends. What CPAP machine does he have? What are the settings? Will he be using the humidifier?

    The more battery the better. Your Dad may not have one, but travel CPAPs use less space, and power. Mine has a heat / moisture exchanger that takes no electricity to use instead of a humidifier...
     
  10. Ironmonger

    Ironmonger New Member

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    I've used a CPAP for over a year now. I can turn off the humidifier and breathing tube heater, and it cuts the power consumption significantly. The CPAP req's 24VDC. I was able to get a 12VDC to 24VDC adapter, and I use an extension cord that connects directly to my battery. I just have a normal deep-cycle battery. I bought a used Honda 2KW inverter- type generator; I run it for an hour or so in the afternoons to top off the battery. I just got a used solar panel & controller, so I'm not sure how well that will work. I haven't had any problems yet.
    The adapter:
    https://www.amazon.com/gp/product/B07P6H994Q/ref=ppx_yo_dt_b_asin_title_o03_s02?ie=UTF8&psc=1
    12VDC Extension cord:
    https://www.amazon.com/gp/product/B019H3MI6E/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
     
  11. dbhost

    dbhost Well-Known Member

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    How are you connecting to the battery? Is it just the onboard battery tied into the PUPs wiring with a 12v port?
     
  12. dbhost

    dbhost Well-Known Member

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    Okay so here it is, what I am using for travel / camping now...

    Z2 standard travel CPAP which lists 20w power consumption. 1.66... amps normal operation, 35w 2.91 amps peak operation.
    https://www.cpap.com/productpage/z2-travel-cpap-machine

    My home / main CPAP is a Resmed AirSense 10 is rated at 90w peak, does not list normal operations. That's 7.5 amps...
    https://www.cpap.com/productpage/re...y1_vKr8fBUo0G9ucIBoX-eoOv8s2zupBoCVFgQAvD_BwE

    My old Respironics System one lists 60w with the humidifier, I can't find where it lists, but I am pretty sure it is around 30w with the humidifier turned off...
    https://www.cpap.com/productpage/respironics-pr-system-one-remstar-plus-cpap-cflex#specs-tab

    Long story short, the Respironics gets 2 days, or at least close to 2 days (nights) off of my Everstart jump box. My Z2 standard does it easily, and my AirSense 10 with the humidifier struggles to make 1 night work.

    They don't list the battery on the jump box, but I can't imagine it is much more than about 20 amp hours.

    The TV for the PU is still a work in progress, so in the mean time, I am working on putting together the following.

    Group 27 deep cycle battery.
    Camco marine battery box.
    12V power port cable with alligator clip ends to connect the CPAP to the battery.

    I will still charge my battery with the Harbor Freight tailgator generator but will need a low amp charger. Due to the limited output of the HF generator, I don't want to exceed the 6amp output of the generator, so I will use a 5amp battery charger.
     
  13. Ironmonger

    Ironmonger New Member

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    I tried connecting to the camper's wiring system, wouldn't work. I bought an extension cord that has a female 12 V socket on one end and two clamps on the other (like jumper cables). I use that to connect to a 12 V to 24 V adapter that connects to the CPAP. So far it's worked great. I've got links to Amazon for these things in another post should you be interested.
     
  14. Desertfunguy

    Desertfunguy New Member

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    I have been using CPAP for about ten years. I used to backpack and rough camp right out of my bag. I bought a tent trailer, to let myself keep enjoying camping, but still enjoy the tent feel. I have several power sources for my CPAP and this has morphed over time. I bought a very cheap unit that has no humidification and is very lightweight for travel. I actually bought two of them to have a backup. I carry a small lithium deep cycle style battery about the size of a motorcycle battery and a 400 watt inverter. It is a 40 amp hour capacity battery, and it lasts three nights without any additional charge. The trailer has two group 27 batteries in parallel and 200 watts of panels on the roof. I also have a 2000 watt Pulsar generator for ultimate back-up when dry camping. I bring a lightweight marine grade charger to keep my lithium battery hot. This has worked great and I could dry camp for a week with no issues.
     

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