18650 Lithium Ion 4-Cell Battery Pack

thingiverse

I designed this unit to accept 4 lithium-ion cells, 2 in series, 2 in parallel, specifically for powering a night light. The cable end is engineered to be epoxied securely into place, while the other end clips on and off - occasionally requiring a screwdriver to release it. This design has been proven to withstand extreme conditions, such as popping open, even when subjected to intense impacts. I personally test this unit by strapping it to my mountain bike frame and riding down steep trails at night in the famous north shore mountains of British Columbia. The unit's durability is also demonstrated by its ability to withstand heavy rain and mud, typical of Vancouver's temperate rainforest climate. I use protected lithium-ion cells from Orbtronic (https://www.orbtronic.com/18650-protected-battery-3500mah-lithium-ion), which are longer than unprotected cells at 68.9 mm.