Danger! Rewiring battery cables is dangerous and potentially hazardous if not done carefully. Take precautions before proceeding, and never touch both black and red wires together with a soldering iron or by cutting

Battery Cable

The battery cable is of decent length for most projects. Unfortunately, we need to cram things into very tight spaces. The stock cable is just too long to fit into the 3D printed case. So we'll desolder the cable from the battery, trim the wire short and rewire it back to the battery. 

Rewiring Battery Cable

I started by carefully removing the layer of kapton tape that's over the voltage and ground pads on the battery. You can also peel back the tape if you'd like to preserve it. I added a fresh piece of kapton tape back over it but if you don't have any, go with the ladder. I secured the battery to my work surface using blue mount tack. Using the tip of the iron, I carefully heated up one pad (not both at the same time!) and slowly pulled the wire away. Then, repeated that process for the second wire. With the cable now free, I cut the wire down to 35mm in length. Strip and tin the two wires. I attached them back to the battery. Follow the + and  labeling on the battery for the voltage and ground connections. The cable is oriented to accommodate for the enclosure.

Kapton Tape

If you don't have any kapton tape on hand, I suggest getting some as they can be handy for future projects. I normally use it to insulate exposed pads on the bottom of PCBs. This helps prevent things from accidentally touching and shorting out. This stuff also handles high temperatures. It's used a lot in different applications like aircrafts, spacecrafts, and x-rays. You'll find this stuff  in electronic manufacturing and 3D printing.

Seal Exposed Wire

Make sure to double check your wiring and ensure the solder joints are solid.

Connect Battery

Now we can plug in the battery to the GEMMA M0. Double check the polarity and make sure the connections are routing correctly – positive to positive, negative to negative. The GEMMA M0 has + and – symbols near the male JST connector. 

Battery Position

The battery cable folds over and fits underneath the GEMMA M0. Notice the wires and solder pads are facing away from the PCB. The 150mAh battery is just the right size to fit under the GEMMA M0. This little package is now ready to install into the enclosure. 

This guide was first published on Aug 09, 2017. It was last updated on Aug 09, 2017.

This page (Rewiring Battery) was last updated on Aug 06, 2017.

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