[Equipment] Building An Ultra-Light CPAP For Backpacking? Possible?

[fortywinks]

Getting ready for a 4-week backpacking trip in the Sierra Mountains in California so I need the lightest possible CPAP device that uses the least power. The lightest commercial one I've found is more than 6 lbs with battery and solar charger—so that's a no-go.

Has anyone experimented with making their own low-tech machine for this purpose? I've been using a regular CPAP machine for 8 years so I can pretty much tolerate any kind of airflow. I'm not a light sleeper.

The part I need help with is thinking it through. Since I'll be asleep, I'll have no idea whether it's helping or just making noise and that's where you experts come in. 

I have a spare CPAP blower motor, what would be the therapeutic effects if I hooked it up a regular CPAP hose at one end and a battery to power leads? Would a 1-way valve help? Would I need a speed control? 

This piece of equipment only has to last 4 weeks so longevity is not going to be a factor.

[Gideon]

You would need a speed control that senses pressure and adjusts to maintain that pressure. My original CPAP, a total brick had a screw to turn to manage the pressure. Actually all you have to do is maintain a single fixed pressure assuming the intentional mask leak is there, so a POT to tweak pressure.

[Crimson Nape]

I came across these PDFs in another thread from March 2019.

Easy to build and affordable CPAP device for adult.pdf
and
Another PDF including pictures, schematics and code
Here is the thread: http://www.apneaboard.com/forums/Thread-...t-DIY-CPAP

[Sleeprider]

The problem is not the CPAP itself. The Resmed Mini is very light and compact until you add in an adequate battery and especially a solar panel. I'd say the O.P has done his homework because 6-lbs is on the bleeding edge of lightweight complete systems that can run for weeks. I'd be interested in hearing what the 6 lb setup is. That is actually very good compared to what I have seen.

It's hard to get away from the nearly linear relationship of weight to power capacity in any give battery chemistry, and while we have thin-film solar panels, they have to have enough capacity to recharge a Li-Ion batter, while traveling from place to place with the panel draped on the pack. Add in cords, mask, tube and charger controllers, and 6 lbs starts looking really good.

[SarcasticDave94]

Is it possible a LiFePO4 battery type may do it for you? Example of one that is suited for amateur radio usage that is 12V at 12Ah is 3.3 pounds and $124 for battery only. Within the radio use battery section, they have 12V from 3Ah to 300 Ah. And they have different voltages too such as 24, 36, 48 Volt deep cycle LFP. They have solar chargers and controllers as well. If it is interesting, look up the website Bioenno Power.

[Sleeprider]

I can source Li-ion with less weight and more capacity that lithium iron batteries, but the lithium iron has the advantage of safety. Speaking from personal experience, the LiFePO4 batteries are destroyed from deep discharge. I own a Shorai on my motorcycle that didn't go a year.

[fortywinks]

A screw? That’s the kind of low-tech thinking I was hoping for.

[fortywinks]

Is it possible a LiFePO4 battery type may do it for you? Example of one that is suited for amateur radio usage that is 12V at 12Ah is 3.3 pounds and $124 for battery only. Within the radio use battery section, they have 12V from 3Ah to 300 Ah. And they have different voltages too such as 24, 36, 48 Volt deep cycle LFP. They have solar chargers and controllers as well. If it is interesting, look up the website Bioenno Power.

[SarcasticDave94]

That battery was a sample. As is it may not be the right battery type after all.

[Bubba in NC]

Pretty good discussion of the available machines in this thread
http://www.apneaboard.com/forums/Thread-...r-8-000-ft

Given the length of your trip I think you're definitely looking at a rechargeable battery and solar recharging. I've got an AirMini.
The AirMini ( 2/3 #) needs 5 AH per night at a pressure of 8 per the ResMed battery guide. The Medistrom 24 Lite weighs 1.3 lbs and I can get about two nights out of it at my pressure of 10. This charging solution is about 2.8# [Commercial Link Removed] Search Amazon for, Solar Panel Medistrom Pilot 12 Lite. It does take 7-9 hours to fully recharge the battery, so I'd think at least two nights worth of storage would be good. Your itinerary (if you have one) might matter. Days in a row of hiking all day and setting up camp at dusk might not give enough time to recharge. 

That's about 5# but you'd probably be at your 6# number when it's said and done. (masks, cords, case, etc.)

Also I assume money isn't a big issue if you can afford to take that long a vacation
I'd ballpark about a grand for the whole setup. I caught a good deal on the AirMini (~$530) and I like it. 

What was your 6# solution?

-----
Moderator Action: Commercial Link Removed

To maintain our status as an educational organization, the only commercial links allowed in this forum are to CPAP-related manufacturer websites.  This is stated in the Apnea Board Rules with details given in the Commercial Links Policy section.

-----