Cell Phone Battery Charger, 5 V - 2 A, Dual USB, 18650 Battery

Yet another, 18650 battery, cell phone charger, among the many. In a "Thingiverse" of a million battery chargers, this is but one, simple design that puts good use of some recycled parts...and hey, it works.

I used two old 18650 batteries from a laptop that was obsolete. I used nuts, bolts, screws, old battery box parts to make up the rest.

Other than that, the charger part is at this location: https://www.ebay.com/itm/5V-2A-Power-Bank-Charger-Board-Charging-Circuit-Step-Up-Module-D