look into the goal zero systems. they have a lot of options for expedition use. im sure there are other brands as well, but this is the one I am familiar with and its available at lots of places.

 

Go for the largest size panel you can easily work with.

 

You might search on 'solar' by @IveofIone

I believe he has mentioned Renogy folding solar panel.

Jay

 

I picked up a 70 watt suitcase solar kit for about $200. If you can get sun for enough hours a day it should work for you. It's small enough that I can actually unfold it in the boat and connect it to the trolling motor battery while I'm using it during the day.

ACOPOWER 12V 70 Watt Foldable Solar Panel Kit

 

How many Watts does your CPAP draw?
How many hours per night?
How many nights?
How many hours per day to you expect to be able to get a full-sun charge?

With that info, you can choose the battery capacity and how much PV panel you'll need.

 

I deal with that issue with my wife's machine when camping. Hers is quite intolerant of the voltage dropping below about 12.4 v. I've found it really reduces the power consumption if you can turn the humidifier function off.

 

Do you have to put it in a dry bag when on the water? Just wondering...

 

I have the GoalZero Sherpa 100 battery and Sherpa 20 solar panel. It was enough to keep my drone and camera, and cell phone batteries fully charged every night on a 4 day trip down the John Day. CPAP probably draws more power. I think I could have kept my batteries charged indefinitely with my system.

 

Oooh really? That's interesting to know. Can I borrow yours for a 4 day trip?? Speaking of which I don't remember seeing any of your drone footage from the JD

 

If you don't know what the power consumption is this Kill A Watt would be a good start in determining what you would need without going overboard. (26$ at Harbor Freight)

Also, the comment about turning off the humidifier is a good one as heating the water is a significant factor in the current draw.

 

Here's one little bit of the video.

 

So cool! We tried to do it this year mid July, but there wasn't enough water so we had to cancel.

 

I too run a small goal zero and its been great the last few years. Charges my phone and speaker in a couple hours of good sun. Thats really the only electronics I run on the river so I'm not sure what the total output could be. I'd call it splash proof but I keep it in the dry box since it isn't very flexible. It does fold up to the size of a sheet of paper though.

 

This:

https://www.inspiresleep.com/

One of my fishing buddies has it and it works great. At least he does not wake up the cabin anymore

 

Very nice video, and interesting discussions about charging. I might have to think about one of those solar systems.

 

Not suitable for CPAP, obviously, but I've had good luck bringing along a lithium jump-starter batter with USB ports for recharging multiple phones, etc.

 

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I'm a Canadian and just sent a query on whether that's available for me in Canada. Seems too good to be true. I've got sleep apnea and scored about 70 for the amount of times I stop breathing during sleep. The mask and hose are just terrible and I just don't sleep very thorough thru the nite but I felt that was the only solution I had. Hopefully it's an available option for me here..

I wear one as well and usually give it a 'good night cussing' as I don it each night and at a few more profanity laced moments thru the night.
I checked my zip code for doctors and was surprised to see only one listed for a rather large population. I must admit that it made me a bit skeptical.

 

I recently acquired a Renogy 200w suitcase for camping. You couldn't take this thing in your raft, it's too big and heavy, but maybe you can apply this data. I also have a battery monitoring system on the travel trailer, so I can see exactly how many amps are going in and out. With good sun, the 220w suitcase will put about 50 amp-hours of charge into my batteries in a day. If you knew what the CPAP was using, perhaps you could scale that number down for a smaller panel.

 

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Check through this guys site for plenty of solar power info: