Vitamin D for mobile phones and other devices
The sun is good for almost everyone in some way. It gives energy for people and devices. There have been solar cells in the world for a long time, not to mention solar power plants.
But this trekking season, there are good, efficient, not too expensive solar cells available and accessible to everyone.
Varuste.net's solar cell selection includes devices of GoalZero, for example. They are an excellent choice for people like me who are not very technologically oriented but want to have easy-to-use devices that they can use without reading through any user’s manuals. Plug and play, as they say.
I bought a solar cell for myself so that I can charge my mobile phone battery (in case of emergency), GPS devices, etc. on longer trips when I have no access to mains current. I also go boat a lot, and with the solar cell, I can use a chartplotter application found on my tablet (serves as a spare navigator) on sunny days.
Besides solar cells, there are also great power banks on the market. They can be charged with a solar cell, too: when it is sunny, you charge the power banks so that they can be used as portable chargers when it is not sunny. Unfortunately, the unsunny days are quite a familiar phenomenon for people like us, living in northern latitudes.
In summary:
You can read about technical features on product pages or in technology magazines, but my empirical test has proved that cells will charge even if the sun wasn’t shining out of a clear blue sky. It just takes a little bit longer. And when the sun is shining, you just need to remember to take good use of it. Simple, easy, and practical.
Charge power banks full before the trip, so that you don’t need to start charging them with solar energy right away.