They are lighter in weight than the Faye dice evil hat sells, but they are good.
USB / DC / Solar Lithium Ion/Polymer charger - v2
Aug 02, 2017
Adafruit is pricey, but the best
This thing is great. Just make sure you mod it to put out 1000 mAh to charge a battery. Check the manual on the Adafruit site for the details on this. Also, get a 6v solar panel that's rated at 5 Watts or better. Otherwise, you will be waiting forever to charge anything.