Power Bank under $10

We’ve all experienced that unique feeling of helplessness and anguish that only a dead cellphone battery can bring. Cut off from the internet and contact with others it becomes impossible to navigate, and what the heck are you supposed to do while sitting around waiting for the bus/train/plane.
how with nothing more than a few tools (3D printer, soldering iron and glue gun), a cheap powerbank module and some 18650 cells(from laptop battery), you can make your own smartphone powerbank.


Here