I use a CPAP machine while sleeping. My DH just finished setting up a d/c system so we can go camping. He tested it with a d/c oscillating fan and it ran just fine. But when we hooked up the CPAP machine, it did not work correctly. Although the pressure read as being correct, it was not as much pressure as I am used to. Also the CPAP display kept blinking on and off. I use a ResMed Airsense 10 and we bought the d/c power cord that is made for that machine. It is connected to the battery bank via a cigarette lighter type plug connected to a fuse box (like the oscillating fan we tested). ResMed said they cannot help us figure it out d/t liability or something. Can anyone offer any ideas as to how we might troubleshoot this? I really want to get out there and camp! Also, my machine is old, will need to get a new one soon. Anyone out there boondocking, what type of CPAP are you using? Thanks for any suggestions.
Running CPAP on DC, need help
- Thread starter SusanC33
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highdesertranger
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Welcome Susan to the CRVL forums! To help you learn the ins and outs of these forums, this "Tips, Tricks and Rules" post lists some helpful information to get you started.
Most of our rules boil down to two simple over-riding principles: 1) What you post should provide good information (like your introductory post), and 2) Any response to someone else's post should make them feel glad they are part of this forum community.
We look forward to hearing more from you.
Well I don't use a CPAP but several members do. Hopefully they will chime in. It's hard to say what the problem is. Can you tell us about your 12v to 120v system. What are you using for a battery(s)? Inverter? I would start by hooking a volt meter up to it and see what happens when you are running the CPAP. If you need a new CPAO anyways they make battery operated travel ones.
Highdesertranger
Most of our rules boil down to two simple over-riding principles: 1) What you post should provide good information (like your introductory post), and 2) Any response to someone else's post should make them feel glad they are part of this forum community.
We look forward to hearing more from you.
Well I don't use a CPAP but several members do. Hopefully they will chime in. It's hard to say what the problem is. Can you tell us about your 12v to 120v system. What are you using for a battery(s)? Inverter? I would start by hooking a volt meter up to it and see what happens when you are running the CPAP. If you need a new CPAO anyways they make battery operated travel ones.
Highdesertranger
do a search on youtube. I have the same CPAP and anything I want to know Is on YT. Rather than "feeling" the DC pressure, go into the internal machine reporting (find out how on YT). It will tell you what pressure the CPAP is running at if you're on DC. Then you can adjust the pressure (also on YT) to your liking,
Sounds like a DC supply problem, either voltage is low, the current capacity is low, or a combination of both, maybe due to the cigarette lighter plug, those rarely work as well as we want them to...
You may have to cut the cigarette lighter plug off and hardwire the cord to your DC supply or fuse panel.
You may have to cut the cigarette lighter plug off and hardwire the cord to your DC supply or fuse panel.
Malamute
Well-known member
Check the power use info on the machine (not the power cord or converter pack on the cord), and the 120v house current power supply and find output volts. If your machine operates at 12 volts or less there shouldnt be an inverter needed, that would be to use the 120v house current power supply on 12 volt, which is very inefficient.
As mentioned, check to see that your plug is working correctly. If it is, check the output of your DC power cord with a multi- meter tester to see if tis putting out the correct voltage. If it has a DC power cord it may work on straight 12 volts which would be the simplest thing for mobile use/ If its less than 12 volts, try another power cord with step down voltage capabilities to give the required voltage from 12 volts.
As mentioned, check to see that your plug is working correctly. If it is, check the output of your DC power cord with a multi- meter tester to see if tis putting out the correct voltage. If it has a DC power cord it may work on straight 12 volts which would be the simplest thing for mobile use/ If its less than 12 volts, try another power cord with step down voltage capabilities to give the required voltage from 12 volts.
B and C
Well-known member
I use a cpap (without humidifier, they suck a lot of power) on my 250 Ah battery bank. I have never noticed a pressure difference between the house and the van. At the house the power brick that plugs into the wall just converts the AC to 12 VDC.
What battery capacity are you trying to use?
What size are the wires going to the 12V power port?
Is the battery at 12.7 VDC when you start using the machine?
Answering these question's will enable us to more fully answer your question's.
What battery capacity are you trying to use?
What size are the wires going to the 12V power port?
Is the battery at 12.7 VDC when you start using the machine?
Answering these question's will enable us to more fully answer your question's.
To help determine if the problem is with the battery, your new 12v cord, or something with the CPAP running off 12v, perhaps try your new setup on other 12v supplies like one on your car dashboard. If it works there, then it’s likely something about your new battery setup.
I’ve run several different CPAPs off my RV 12v system for several years and never noticed a difference in pressure, but maybe I am not very sensitive to it.
As a backup, I always have a small Ryobi inverter with a fully charged 4 or 9ah battery so I can switch to AC power in a pinch.
I’ve run several different CPAPs off my RV 12v system for several years and never noticed a difference in pressure, but maybe I am not very sensitive to it.
As a backup, I always have a small Ryobi inverter with a fully charged 4 or 9ah battery so I can switch to AC power in a pinch.
I've been looking into CPAP usage and one of the YT channel I watch is a gentleman in Canada. He does a lot with electronics in his ambulance build, and has his CPAP hooked up, on DC I believe. I have a ResMed 10(?) as I recall off the top of my head. I emailed him about it and this was his response.
"You can get a 12VDC to 24VDC 10 amp step up convertor on Amazon for around $30 CDN. When i run anything electrical or electronic i never exceed 50% of the product rating.
I run my 24" monitor and charge my laptops with 12VDC to 19VDC converters for over a year now. I actually disconnected my inverter I haven't used it for 9 months.
Let me know if you have any questions about connecting it i can do a drawing for you is needed."
Check out his YT channel. Contact him with any questions. He is super nice and helpful.
His channel is Healthy Adventuring in Pallet-Ive Care.
The other option, if you have the budget, would be a portable power station (Jackery, etc) to have dedicated for such use. This would be a bit more $$$ overall, but for simplicity, may be something to think on.
"You can get a 12VDC to 24VDC 10 amp step up convertor on Amazon for around $30 CDN. When i run anything electrical or electronic i never exceed 50% of the product rating.
I run my 24" monitor and charge my laptops with 12VDC to 19VDC converters for over a year now. I actually disconnected my inverter I haven't used it for 9 months.
Let me know if you have any questions about connecting it i can do a drawing for you is needed."
Check out his YT channel. Contact him with any questions. He is super nice and helpful.
His channel is Healthy Adventuring in Pallet-Ive Care.
The other option, if you have the budget, would be a portable power station (Jackery, etc) to have dedicated for such use. This would be a bit more $$$ overall, but for simplicity, may be something to think on.
My CPAP cord has a brick that converts 120 volt AC to 12 volt DC. So I bought a cord from Amazon with the correct DC plug on the end and just made a 12 volt extension cord to go straight to it. The fuse is in the 12 volt plug. I have a ResMed dreamstation.
I wish my ResMed was a 12v device. I'll have to resort to a buck converter to punch it up when I get to that point.
If you're blessed to have a 12v device, that will do it.
If you're blessed to have a 12v device, that will do it.
mpruet
Well-known member
Are you sure that you have 12 volt system and not a 6 volt?
user 29855
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I have a Respirex unit, and a 12 volt power supply for it. Using an inverter to change 12 volts to 110 volt ac is very inefficient, especially with the cheaper units found on Amazon and Ebay. This unit converts 12 volts to 18 or 24 volts (I don't remember which) using a more efficient method called boost. The description is philips respironics DC adapter. Search Amazon, you'll find it. Make sure it's compatible with your model. I've had mine for about 5 years, and use it every single night. I paid $89 for mine.
BlueMarkOhio
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Some CPAP machines have the polarity reversed in their DC power connections. Who knows why. You may need a special power cord or even a specific DC to DC converter to make yours work. Check the faqs and forums for your particular machine to find the right combo.
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Many (most?) CPAPs cannot run the humidifier when on DC power - it is too much of a power drain and even if it runs, it could cause brownouts.
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Looks like the ResMed Airsense 10 requires a 12v to 24v dc to dc power converter to run on battery, so I'm guessing the problems the OP is seeing is due to undervolting. Here is an example of such a device (not an endorsement): https://www.amazon.com/KFD-Airsense-AirCurve-Machines-Replacement/dp/B07P6H994Q
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Many (most?) CPAPs cannot run the humidifier when on DC power - it is too much of a power drain and even if it runs, it could cause brownouts.
.
Looks like the ResMed Airsense 10 requires a 12v to 24v dc to dc power converter to run on battery, so I'm guessing the problems the OP is seeing is due to undervolting. Here is an example of such a device (not an endorsement): https://www.amazon.com/KFD-Airsense-AirCurve-Machines-Replacement/dp/B07P6H994Q
