21700 powerbank- 20000 mah dual output/input

21700 power bank for charging phones, electronics, and for powering USB devices. The USB-A ports are 2 amp output apiece and the USB-C ports are 2 amp inputs and if you plug them both in you can charge the power bank twice as fast when it needs charged. 

Material list:

This print

4- 21700 cells( I used Samsung 50E)

2- charging/discharging modules( same as my 18650 power bank module from amazon

4- #4 x 1½" pan head sheet metal screws

2- #4 x ½" pan head sheet metal screws

4- #2 x ¼" pan head sheet metal screws

Included stl files of module housings with two styles of eyes so you can put a carabiner or loop to hang it up.

Remember Lithium cells are dangerous! Only build if you have adequate knowledge and experience with lithium cells! Also solder your wires first to the modules first then hook to your battery. :-)