Simple 3d Printed Li-Ion Battery Connector (18650/21700)

I was looking to connect a circuit to a Li-Ion battery. However, soldering is quite difficult on these cells and spot welding not accessible to all of us. So I decided to make a simple 3d printed cap. It is press fit and holds the wire in place. Print twice and chose the correct .stl file for your cell size.The .stl files for 18650 and 21700 cells can be found for free on thingiverse.

I recommend using ABS+. It is easy to print and more robust to temperature and UV than PLA or PETG. Put a blanket on top of your printer if you do not have an enclosure.

• ESUN ABS+
• .stl files
• wire
• tape
• multitool

• Choose .stl file according to the cell size
• Print twice per cell
• I recommend ABS+, but PLA and PETG should work too
• Use at least 20% infill and 0.2 resolution.
• Support is not needed when printed bottom down.

• Strip the outer Insulation of a wire
• Twist then fold the blank wire. It should fit nicely into the cap.
• Use a small piece of tape to stick the blank wire to the battery terminal. Black wire goes to the negative terminal, red wire to the positive terminal.
• Push the 3d printed cap over the terminal. The wire runs through the cut out. It is press fit, so you might have to push hard.
• Repeat on the second terminal. Use tape to stick the longer wire to the battery.

The connector should work now. You can test using a multimeter oder voltage tester.

I hope you enjoyed this instructable! Feel free to like and share.