Start here: Direct USB Charging Battery
This is obviously OT on DIY, the best fit would be electronics.
So, Close, Select "This question belongs on another site in the Stack Exchange network" and the only option I'm presented with is
"belongs on diy.meta.stackexchange.com discussion, support, and feature requests for this site"
My guess is that the belongs on another site option is to recommend a mod migrate the question. But Meta is not where it should end up.