Single 18650 External Battery

thingiverse

This is a small, portable, rechargeable external battery that utilizes a single high capacity 18650 cell to output power through a USB port for uses such as charging a phone, or anything that takes 5V. The design is very simple, a single 18650 battery is wired to a mini 5V Step Up converter which can be found here (https://www.amazon.com/gp/product/B07D3SQYKJ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1). It takes power from the battery and steps it up to 5V which is outputted via USB-A and recharged by micro USB. A single Red LED shines through the shell brightly, and is easily visible outdoors, when it is charging, the LED flashes red, and when it is full it is solid red. When discharging, like when charging a phone, the light will be solid red, and flashing red when the battery is low. I use a 3450 MaH 18650 which is enough to charge my phone fully before the external needs recharging. Assembly is just wiring the negative of the 18650 up the side of the cover, where there is a small groove, and I glue it shut once everything is working.