Solar panel to charge Anker power bank for Backcountry CPAP use

did you see https://backpackinglight.com/forums/topic/cpap/

that has some info about cpap that might be useful

Thanks Jerry.  Not bothering with the CPAP probably won’t kill me for 5 nights.  I’ve always slept fine (ecept on backpacks, just the way it is) but my sleep test was done because of elevated pulmonary artery pressures (Presumably really because of severe aortic regurgitation, thus the valve replacement).  My AHI was around 36 on the sleep test. Central sleep apnea.  My cardiologist would prefer I stay on CPAP to decrease vagal tone because of heart rhythm issues after the surgery. AHI on CPAP usually 1 or less according to the machine.

Airmini at pressure of 14 draws less power than full size machine, probably 7-10 watts.  I can live without humidification when on trips.

Gotta look into the lighter weight battery Kevin mentions in the forum you linked. Maybe see what solar panel he uses.

My very general tip is to be very cautious about the “power” promoted by the solar panel manufacturers. My experience has been that it is wise to “over-size”.  I acknowledge that does not sound very “light” but the heaviest thing in your pack is the item that doesn’t work, or work adequately.

Personally, even living in the sunny desert southwest US, I’m skeptical of the value of a solar panel strapped to a pack, particularly a light solar panel. The percentage of time that it’s correctly oriented to the sun and unshaded has got to be low.

If you like taking a multi-hour break around lunchtime, then sure!

Personally I would take an extra 2 batteries. 🤷‍♂️ But I have only done 2-night trips since getting my CPAP.

Random note – my AirMini takes 24W, not 65W. Are you sure you’re not getting data about a full-size AirSense? I can send you Amazon links to the setup I use (no solar panels) if you would like.

The airmini needs 24 volt input.  I think 65 watts input as well..  I use this adapter:

20V PD USB-C Power Supply for ResMed AirSense 11 Air 11 Airmini 65W 20W ResMed CPAP Charger DC Coverter Cable by FLGAN. Can search for it on Amazon (how do you post links that work on this forum, btw?).

Its usable with an Anker wall charger as well wita usb c output.  More compact than the brick that comes with the Airmini.
I may just take an extra battery. At a little over a pound each :(

maybe manually set the CPAP to minimum pressure – 4 – and it will consume less power.  If the resultant AHI as reported by the cpap is acceptable.

heart valve replacement and AHI of 36 is pretty severe – I can see how in your case you definitely want the cpap

there are previous threads calculating how weight wise, solar panel doesn’t make sense unless you’re gone for more than a week.  Otherwise, it weighs less to take extra battery

I may lowera tahe pressure of the cpap to increase battery life.  My prescribed pressure is 14 but it takes time ramping up from a start of 4 and it seems fine.  Not even sure how accurate pressure calibration is above 8500 ft. As long as I keep breathing!

Pretty convinced now tahe solar panel thing probably not worth the weight and hassle.  More batteries and try to save more weight elsewhere in the kit.

Alex- I’d like to see the Amazon links to the setup you use.  thanks

Sure!
Here is the cord:

CASIMY DC 24V Power Cord… https://www.amazon.com/dp/B0BQL6JHH2?ref=ppx_pop_mob_ap_share

and here is the battery (I’m sure bigger and heavier than yours). Longest trip I’ve taken with it was 2 nights and it was still at 2/4 bars at the end, including recharging my satellite messenger which I accidentally left on overnight.

Talentcell 24V Lithium ion… https://www.amazon.com/dp/B07SWBS55F?ref=ppx_pop_mob_ap_share

I should mention, I think my pressure range is 6-10 [units, I forget the units]. I think I left it on APAP where it automatically adjusts the pressure within the range, though it would be more efficient at a constant pressure.

2-night trip I slept at 9200’ and 11,400’.

try manually setting the pressure to lower levels and look at the AHI that it reports.  Lower the pressure until AHI is too high.

hold the rotary dial button and home button down for several seconds to go into service mode.  Then set the starting pressure and end pressure to the same value.

my apnea doctor told me to do this.

Then she retired so I went to another, that was a PA, and she said that was illegal and reprimanded me severely.  She set it back to the recommendation from the sleep test.  And that I absolutely had to take my cpap with me backpacking.  When I got back home I put it back to manual mode.

A third apnea doctor told me that was fine as long as the report AHI was below 5.  And between 5 and 15, it’s not critical to use cpap for health, just patient comfort

I have mild sleep apnea so not real applicable to your case.

These are just questions for your apnea doctor.  Like, how high can AHI be and still be healthful.  Don’t follow medical advice from anonymous internet people : )

Here is a good tutorial about solar charging on trail. Note that the author frequents deserts and does not use a sun umbrella, so his solar cells get a lot of sunlight. YMMV (and probably will).

https://www.joshbukoski.com/solar.html

Wow, thanks Bill! I frequent deserts but AM a sun umbrella user. I’ll give it a shot I guess!

Jerry, as a physician I can say the PA who told you it was illegal to adjust your machine was full of air pressure herself.  I’d tell her to call the cops.  I have gotten into the clinical settings of the airmini before. Maybe I’ll try the airamini at a loawer setting at home and see how ita goes.

Thanks for the link , Bill.  I’ll look at that ASAP

Alex.  As I mentioned above I got this power cord that allows powering the Airmini through a USB C output from a power bank or wall charger instead of being limited to a barrel connector.

https://www.amazon.com/Supply-AirSense-Airmini-Charger-Coverter/dp/B0BV1J88GV/ref=sr_1_3_sspa?crid=1IJJOQAL8P4UH&dib=eyJ2IjoiMSJ9.To4xgIBGx9mtSZgK4s-mGZJOYwEcxstx3r1WkSpsFYlEXxl-B0zwLxCn7Utq0_YkbzVZ4UgvGBmDPhIbmJ-00UO9BeMDOa6DeGw1VakTKPOmxvBAFYYcjI8PsHzeI3f7m7xAVcX8I4VNzhtCM7S8g-2tgrmrsUsHeWh-S4IJIfepm3vlBB83xqQunCqb06NnSgW9USgEIxCBVYsb7SKY-LqkiXY0nJfgtSaK3zZ_e4XmHnY9u1kQHYsOEuX4eKqyCG0tLBdxg98IFmJasIYkoevwAnvJC_IUUDsgrmufKNk.qhfltAmbAGvvtPimldpcRIOar86ssHvXgS8Yw1zuoaM&dib_tag=se&keywords=resmed+cpap+charger+dc+converter+cable+by+flgan.&qid=1718392367&sprefix=resmed+cpap+charger+dc+coverter+cable+by+flgan.%2Caps%2C289&sr=8-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

I think what she was referring to, was that to qualify for insurance, you’re supposed to use it successfully for a period of time.  During that period, you probably shouldn’t screw with the settings, although “illegal” is a bit strong

Medistrom has a 50w solar panel that works well.  This is what I use backpacking.  The Medistrom battery, while reasonably light is way to expensive.

Thanks! That looks awesome and I would go that way if I were starting over! Maybe I will still go that way, seems way more versatile to equipment changes.

Has the OP thought about renting a llama? Or hiring a horse packer to carry the bulk of the weight while hiking? I’ve run into folks who hired a packer out of Reds Meadows. They would hike with day packs and meet the packer at a prescribed campsite. Alex, after all you’ve been through, lugging even more weight from cpap equipment, plus the panel or battery, is really asking a lot on a first hike. In any case I hope you do a modest one or two night shakedown trip before this big hike. I’m a nightly cpap user who luckily managed to sleep well enough out hiking. I don’t  have central anea however. Once I developed atrial fibrillation (now not an issue post ablation) I continued to hike, but scaled things back.  It took  me several years to bow to reality–MY reality, not yours necessarily! Again, looking for a way to lessen the weight (a llama!) while carrying everything you need first time out may offer a different approach that works. Think outside the box!

edit: I once ran into the son of a famous photographer who hired a guy out of Bishop to help carry his own camera equipment. Another possible route.

Actually Abraham is the OP and I’ve actually been on 3 trips (not long ones) lugging my CPAP and batteries. See my latest trip report from the Trampas Lakes, 40 lb. total pack weight for two nights for me and the dog, sigh.

Apologies,  I meant to address Abraham! with the heart issues etc.

Jscott, appreciate the concern but I’m not going to rent an animal to carry my stuff.  It’ me or nothing.

The new heart valve is doing what it should, acting as a competent aortic valve and not a leaky one.  Done a lot of walking, some inclined treadmill and will do some hiking in Yosemite next week.  Had a couple episodes of afib soon after surgery (common, I was told) but none since (knock on wood).

The sleep apnea thing is an annoyance, mostly with all the cpap chores.  I sleep fine (except on backpacks, since forever) but don’t expect more than the  burden of extra pounts of cpap gear I have to shlep.

How I’ll do at high altitude remains to be seen.  I would spend some days at higher altitude (such as in Mammoth) for more acclimation.  Will it be enough? Not sure.  I told the leader of the group I’m going with I’m willing to turn back the first day if the climb is too much for me.  Not gonna be a hero.

Inspired by this post, I got the power cord Adam is using and a power bank with a USB-C output. A question in my mind – how much efficiency is lost by conversion from whatever USB-C puts out (looks like 5-20V) to the 24V needed by the AirMini? I will test eventually, just wanted to see if any engineering types had intuitions for about what percentage loss we’re likely to see.

Necro-thread:

Boosting from 20V to 24V is between 85% and 95% efficient, depending on the device.

I chose to order one of those cable/converters and also to get a Zopec Explore Mini battery pack. Slightly more expensive than some random Anker, but good Philips cells and an auto sensing DC out with the right short cable, and likely better customer support. Oh, and it works as a UPS, too.