Looks like the constraints of travel by Kayak will put the kibosh on using solar.
I see solar panels in the 100 Watt, 12 Volt range are about 1000 sq-inches; and weigh 17 pounds.
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
With the research I did for my trike-camping, ignoring the cost of the gear, the only real solution was to have enough battery power for the entire trip, or to where there were planned stops with power for recharging.
If 4hrs of PAP per night were considered enough, and $$$ was no object, the 'Z1' with multiple battery packs would be the way to go, but I think you'd end up closer to 5lbs total weight. (getting two to three nights per battery at 4 hours per night - the company has gotten 2 8 hour nights from a battery, but there are variables)
*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.
"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
This thread is a couple of months old, but I thought I'd share my experience with the Transcend 2 and the "multi-night" battery. I got it for travel to to developing countries and multinight camping trips. I use 9cm pressure, and was initially able to get two 8 hour nights. Not anymore. I was getting about 5 or 6 hours the second night until I gave up trying to use it for two nights.
In terms of humidification, I use the on head kit for waterless humidification. It works REALLY well for me. It does look a little goofy, but not having to bring all the tubes along saves a lot of space in the travel bag. As I imagine you'll need to put everything in waterproof bags or cases for kayaking, that's something to consider. On top of my head, it is louder than my regular machine on my bedstand. I use silicone earplugs, like mac's, whenever I use my travel cpap and I don't hear anything. Also prevents snoring from camping buddies from waking me up! I'm considering getting a battery from Goal Zero (they have ones with a regular wall-type outlet) I'm hoping to be able to use one of those to top up my cpap battery to finish out the second night. They also have solar power arrays to connect to their battery. The advantage, in my mind, is that could also be used for other items too.