18650 Dummy Battery

This is a 3D-printed 18650 dummy battery designed to replace a standard 18650 Li-ion cell and allow a device to be powered from an external battery pack or power source.

The dummy battery uses M3 screws at each end as electrical terminals. Electrical connection to each terminal can be made in one of two ways:

Using a spring steel battery contact tab secured under the M3 screw to provide compliant, pressure-based contact with the device’s battery terminals

Using a ring (eyelet) wire connector secured under the M3 screw for a rigid electrical connection

Flat washers may be added as spacers to fine-tune terminal height and ensure reliable contact with a wide range of battery holders and spring contacts.

Polarity is clearly marked on each end of the dummy battery to prevent wiring errors.

This design was created for a LoRa radio project, but it can be used with any device that normally operates from a single 18650 cell at 1S Li-ion voltage (approximately 3.0–4.2 V) and can be used in