I bought one of these a coujple of years ago and have always felt its recharge speed when using the solar panel was so slow as to make me question if it worked. I am going away and so checked on what people thought. Here are my notes and links. …
The charging speed is very slow, this video measures a full charging period in days. The comments on the amazon sales page suggest that it’s better than nothing if one has no availability from the grid so for short outdoor camping/hiking holidays it could be good, particularly as a fully charged bank will charge up my phone several times, although if you have more than one device, it may not be good enough. Having written this, I took it away on a trip and put it on the window sill, it was over 3/4 full and took three days to fully charge, in line with the video linked to above.
Here’s a negative review, Should I buy a solar power bank? but I also found the more evenly expressed article, “why, what and how which introduces the concept of having the device in two parts, a power bank and a solar charger. I also think these people have something to sell.
For me the big lesson for today is that solar charging is very slow. I assume it’ll get better, but I am not sure it has yet but my bank is couple of years old. This is not yet going to save the planet.
It caused great interest at Tallinn airport, where I was told, it is only just permitted on aircraft as hand luggage. Probably designed to be so, but glad I was able to keep it; they made me throw my OJ away,
Another point us that mine came with both USB B & C charging ports; using USB B for the first charge of the bank was an incredible long period, 10’s of hours if I remember correctly. This could just be because its a big battery and has a lot to fill.