I needed a lithium-ion battery for my Bluetooth speaker project, but I only had an 18650 available. So I designed and built my own battery holder.

This is a print-in-place design that requires no metal plates, springs, or other additional components. You simply insert the wires directly into the holder, and it’s ready to use. It’s also compatible with both standard 18650 batteries and protected ones.

Although the print profile is optimized for PLA, I recommend using PETG to achieve greater flexibility and durability.

It’s also useful for learning electronics through hands-on projects and experiments.