3s 18650 tripack endcap with integrated loop for zipties or velcro straps

thingiverse

I was left with plenty of salvaged 18650s that I needed to use for my R/C planes, specifically to build compact 3S battery packs. To achieve this, I designed a triangular endcap that securely holds three 18650s in series. The design features an integrated loop, allowing you to easily attach it to whatever you need using velcro or zipties. My Panasonic 18650s fit perfectly, but keep in mind that other brands might be slightly fatter, so scale up the design by about 1% as a precaution. I highly recommend securing the caps in place with a flexible adhesive like Sikaflex (or regular silicone) to protect your wires, balance leads, and cells from shorting out due to water or other environmental factors.