Originally Posted by
Bezalel
I never had much luck charging USB batteries directly from my solar panel (GoalZero Namad 7). The panel's USB port only provides 5V in optimal conditions and with lower voltages most batteries won't charge. You're best off with a battery designed to charge off the solar panel like the Voltaic V39.Personally, I'd suggest a dynamo hub but if you go with solar make sure your batteries will accept a trickle charge.
This is so true. I was using a panel for about 2 month on my current trip, when I lost the connection that directly connects to my batteries. I was forced to use the USB side of things, and honestly unless you were in perfect light (never when riding a bike) nothing would charge. Usually things were discharging more than charging!