This is a usb charger I've been experimenting with that runs off variable voltage inputs in the range of 5-32 volts. Inside is a DROK LM2596, three diodes, a 40mm fan, and a USB A jack breakout with resistors for charging iPhones. (weve figured you out, apple) Right now I have some solar panels configured so I can directly power my 5v devices from the sun. The regulator can probably provide amps for two or three USB A outs instead of one. I printed it in PLA and used a 3mm-0.5 Tap with m3 hex nuts and bolts.