CPAP system backup/camping power

[PNPmacnab]

I just cut the cable from the 120V AC adaptor. You could put a 3 pin plug on each end to connect it back together when AC is available. I have not found an off the shelf cable that will work. A HP plug is similar but has a plastic spacer on the end which tells the machine the plug isn't fully inserted. There are boost converters that can adjust 12V to 24V and that is adjusted to 24.0V DC. The plug has three connections. Outside barrel, inside barrel, and center pin. Believe outside barrel is neg and inside is positive 24V. Center pin is 3.3V supplied thru a resistor.

In the above mod the two resistors are in series with the center pin connected to the junction of the voltage divider.

[coarsegoldkid]

I checked my old paperwork. My Autoset 10 has a 24V supply. To operate off exact 24V and fool the machine into thinking it has an 85W supply pack, the center pin must look like a 3.3V source connected to a 2.7K resistor. Only two resistors are needed to do this. The Thevenin equivalent is a voltage divider with a 33K resistor to the +24V and a 3.3K resistor to common. These values are common and close enough that the exact 1% resistor values are not needed.

I'm trying to visualize this. Some how one still needs to get to the center pin. Is there a cable one must hack?

[PNPmacnab]

I checked my old paperwork. My Autoset 10 has a 24V supply. To operate off exact 24V and fool the machine into thinking it has an 85W supply pack, the center pin must look like a 3.3V source connected to a 2.7K resistor. Only two resistors are needed to do this. The Thevenin equivalent is a voltage divider with a 33K resistor to the +24V and a 3.3K resistor to common. These values are common and close enough that the exact 1% resistor values are not needed.

[SunEagle]

Did you ever price out a 30 Ahr LFP battery? That would have eliminated the need for a cart and the charge efficiency of LFP would have let you use a smaller capacity battery than the 65Ah Optima. Also, LFP doesn't self discharge like lead so it would stay fully charged between uses.

Back when I built that system I had not learned enough from others what not to do. Going with an LFP battery would have made my system much more portable and easier to use.

[Ampster]

I built a small solar/battery system that can easily provide power for my CPAP all night long. It includes an 80watt folding panel, 15amp PWM CC, 65Ah Blue top Optima battery and a 300watt inverter. I use a hand cart to move it around and the battery sits in a box that has terminals, 2 cigarette plugs and a power level indicator. I can get about 200wh out of the system at night and get the battery recharged during the day. Total cost was about $500 which I doubt you can find prepackaged anywhere. My only issue is that I should have gone with a 100watt panel for that 65Ah battery.

Did you ever price out a 30 Ahr LFP battery? That would have eliminated the need for a cart and the charge efficiency of LFP would have let you use a smaller capacity battery than the 65Ah Optima. Also, LFP doesn't self discharge like lead so it would stay fully charged between uses.

[coarsegoldkid]

I have found a DC to DC converter on Amazon that's for the Airsense10. Apparently it up converts to 24vdc for the A10 and massages the 12vdc to 12vdc for S10 machines needs on the ID resistor in the connector of the unit..Purchase the female cig lighter / jumper cable at the same time as it's not included. This non-OEM converter is less than half the cost of one from Resmed. Going this route is easiest. Now for the battery. Input DC: 12V-24V~12A Max Output:24V 3.75A 90W ;--Please confirm the specifications and plug size before purchasing!If you can't make sure,pls feel free to contact us
Compatibility: ResMed Airsense 10 Series: AirSense 10, AirSense 10 Elite, AirSense 10 AutoSet, AirSense 10 AutoSet for Her CPAP Machine with HumidAir Heated Humidifier; Fits Resmed CPAP and BiPAP Machines S10 370001 +24V 3.75A 90W; ResMed AirCurve 10 Series CPAP and BiPAP machine: AirCurve 10 S BiLevel Machine, AirCurve 10 VAuto BiLevel Machine with HumidAir Heated Humidifier

[SunEagle]

I did start with portable power station as that is the proper terminology. I included the marketing hype name as some people are more familiar with that term. Thank you for the statement about disconnecting the CPAP during charging. It most likely would not be a problem, but when dealing with an expensive machine people rely on, it is good practice.

I built a small solar/battery system that can easily provide power for my CPAP all night long. It includes an 80watt folding panel, 15amp PWM CC, 65Ah Blue top Optima battery and a 300watt inverter. I use a hand cart to move it around and the battery sits in a box that has terminals, 2 cigarette plugs and a power level indicator. I can get about 200wh out of the system at night and get the battery recharged during the day. Total cost was about $500 which I doubt you can find prepackaged anywhere. My only issue is that I should have gone with a 100watt panel for that 65Ah battery.

[PNPmacnab]

I run my A10 off a 12V battery at my camp and a 12 to 24V boost converter. Don't know where you got 19V. However, it likely has internals that would run that low. I used one of those $6-7 adjustable boost converters and set it to 24V exactly. That cable is special and a standard HP cable will not work. Maybe if you ground the plastic end off. If you notice, pulling the plug out slightly causes an error to be displayed on the screen that the plug is not fully inserted. The center pin requires a 2.7K resistor to a 3.3V source. Do not power the center pin directly. It designates a 85W supply. There is an easy thevinin equivalent using two resistors from the 24V. I could look it up if interested. I just cut the DC cable on the AC power pack. You can just wire up a three pin connector at the cut and have both worlds. I never did that because these packs are only $10. Still have it if an emergency should happen. I even have mine on a digital timer so it turns off in the morning should I leave early and forget to turn it off. That can be a really rude alarm clock if I sleep late.

[BoloMKXXVIII]

I did start with portable power station as that is the proper terminology. I included the marketing hype name as some people are more familiar with that term. Thank you for the statement about disconnecting the CPAP during charging. It most likely would not be a problem, but when dealing with an expensive machine people rely on, it is good practice.

[Mike90250]

Please stop using the phrase "solar generator". Such a thing does not exist. A generator is a revolving magnetic field. Just because Marketing Bozos use it, does not make it right.

A note of caution about using a solar powered charger, Many will produce 15V to the 12v battery, in order to charge the battery faster in the limited solar hours. Your CPAP will not likely be operating during that time, and so you should un-hook the 12-24V adapter until bedtime, when the system will be closer to 13v.
I'd advice you to use the factory converter cable, and let it be responsible for the proper operation of your machine.

[BoloMKXXVIII]

I would like to run my Resmed Airsense10 off a small solar system essentially a solar generator at my cabin. The Airsense10 comes with a power brick AC120 to DC19dvc converter. The Airsense10 is labeled 19 Volts input. However, Resmed sells a 12vdc to 24vdc converter for car camping. This suggests to me that the Airsense10 will operate on 24 vdc. That being the case I should be able to build either a 24vdc or 12dvc LIPo battery and charge with a controller off a panel. If a 12vdc then I get the Resmed DC to DC converter. If 24DVC I run it straight off the battery. What do you think?
What I like about building the battery from discrete cells is if later I decide to build a cabin size solar system I'll buy more cells and panels plus the rest of the kit to make more capacity and run the cabin on AC.

If only it were an issue with voltage. I don't know what the CPAP manufacturers do, but I was unable to make anything work but their "official" cable. Matching voltage and amperage did not seem to be enough. I would go with their official car cable and build around it. A pre-built portable power station (solar generator) would probably be cheaper than building one yourself. Just make sure it has a regulated 12 volt output. Most do not.

[coarsegoldkid]

I would like to run my Resmed Airsense10 off a small solar system essentially a solar generator at my cabin. The Airsense10 comes with a power brick AC120 to DC24dvc converter. The Airsense10 is labeled 24 Volts input. However, Resmed sells a 12vdc to 24vdc converter for car camping. This suggests to me that the Airsense10 will operate on 24 vdc. That being the case I should be able to build either a 24vdc or 12dvc LIPo battery and charge with a controller off a panel. If a 12vdc then I get the Resmed DC to DC converter. If 24DVC I run it straight off the battery. What do you think?
What I like about building the battery from discrete cells is if later I decide to build a cabin size solar system I'll buy more cells and panels plus the rest of the kit to make more capacity and run the cabin on AC.

[BoloMKXXVIII]

I use a Respironics CPAP (with 12v cord) and when camping I do not use the humidifier. I used to use a 80Ah AGM battery but it was difficult to move around without killing my back. I built a 20Ah 12v LiFePo4 battery pack and have managed to run 3 nights without having the low voltage limit cut off power (set for 11v). I admit I do not sleep long (camping or otherwise) and only use 8" pressure. I found attaching a single 100w 12v solar panel to the battery via a PWM controller keeps the battery topped off during the camping trip. Knowing I have at least 3 nights even without the solar panel gives me comfort.

[PNPmacnab]

Humidifiers and heated hoses are a super big drain, I turn them both off. That drops me down to 6-7 AH a night. I don't really miss the humidity for four months since it is not a dry area. Also built my own power pack to boost 12 to 24 which is on a timer so it doesn't run all day, a very rude alarm clock should I sleep late.

[Buck Rogers 2000]

I've used a Goal 0 Yeti 400 (not lithium) for my CPAP. With the humidifier on, it drained 60% of the (AGM) battery in one night. If you have a solar panel large enough, with enough sunlight, theoretically you could boondock for quite a while. Of course, turning off the humidity would stretch it out quite a bit. Note: If you're interested in this unit, I don't recommend Goal 0 lithium units. Their batteries aren't user replaceable, they incorporate PWM controllers and their input power is throttled.