Luke: "The GoalZero Guide 10 Plus solar charger/battery setup worked great. It charged what needed to be charged (iPhone, Spot Messenger) and could likely have charged the sat phone as well, had we remembered the correct attachment.
Some plusses: it's pretty light, it's durable (as in, I didn't manage to break it), it's weather resistant (stood up to some light showers), and it looks cool. I still use the battery pack as a day-to-day backup phone battery.
Some minuses: it's pretty finicky (there are quite a few cables to deal with, thus the forgotten adapter), and the GoalZero batteries don't play nicely with the Spot Messenger. What I mean is that even with a freshly charged set of AAs from the GoalZero, the Spot still thought it was operating on low batteries. Why the GoalZero batteries weren’t powerful enough to drive a 'full charge' signal I don't know. I do know that this was happening even with fully charged GoalZero batteries, as I retested it myself later after the trip.
That being said, I heartily recommend GoalZero’s stuff – this setup was the first 'field-charging' rig that I have used that actually works!"