How to Charge Rechargeable Batteries Via a Micro USB Port in a Portable USB Charger Answered
I recently made one of the Altoids box USB chargers that have been popping up all over the site and it turned out great, but now I'm looking for a little more of a challenge, so for my next endeavor I'd like to make a portable USB charger which uses rechargeable batteries that can be recharged while still in USB charger through a micro USB input (like how you plug in a phone to charge the internal battery). I've seen a few projects that use solar panels to achieve a similar result but (perhaps just due to my own limited knowledge) I couldn't figure out how to make it work with a micro USB port.
Also, if possible, I'd love to be able to use the 18650 (EFest IMR) as the rechargeable battery/batteries. I have a few of them that I use for e-cigarette mods and they hold a good amount of juice so why spend more money on rechargeable batteries when I already have some. But if using more conventional batteries would make things easier then that's not a problem at all.
I can't wait to hear the community's input on this. And to those who are the knowledgeable ones in this field, don't feel obligated to say everything entirely in layman terms for my benefit - what I don't know I will look up; how else are we supposed to learn new things anyway? Thank you for your time and for any help you can offer!