You will probably need multiple options.
The Biolite stove mentioned - IU saw a review and it said that it doesn't put a lot of power out.
Charging off of disposables - saw a review that said that each AA battery adds less than a bar to the average cell phone.
I suspect the dynamo would take an awful lot of spinning to charge a phone any significant power. What do they say - 10 seconds of spinning gets you a minute of light out of an LED? LEDs draw just about nothing.
I used a cheap solar panel to recharge AAA batteries on a 10 day trip I did, so we could keep a VHF going. Had 2 sets of batteries, so charged one while used one. Had charger in clear dry bag on back deck. Just barely made it. Another day or two of fog and I would have been out of power.
I suspect SPOT doesn't meet your need of posting to Facebook - yeah, you can post short OK messages, but not photos and such.
If I was you, I'd go or a solar system in clear dry bag. Something like the product mentioned. But I would also get a second option (disposable battery one, or the dynamo) as a backup.
First Need Purifier
Classic Freestanding Rack
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