Milwaukee M12 Dummy Battery AC Adapter

This is a remix of the M12 battery enclosure originally designed by CuriousTech on Thingiverse. I’ve filled in the space where the 18650 cells would normally go and opened up a few holes around the enclosure, and merged the middle part with the top. The idea is to make a dummy battery (basically an AC adapter) so you can run your M12 tools straight from the wall. You’ll just need your own 12V power supply to make it work.

 

This setup is best for low-power tools like entry-level drills, radios, or work lights. Once you get into more power-hungry tools, it starts to become less practical since the PSU's become more big/expensive/loud and you'll need thicker wires to handle the load as well. I’d say staying under 6 amps is ideal—power supplies are still pretty affordable at that level, and 18 gauge wire, for example, is still nice and flexible.

 

Print Settings

• Print both pieces upright
• No supports for the bottom piece
• min. 3 walls
• 3 bottom layers
• 4 top layers
• 10% or higher infill

 

Required Hardware

• A 6.3 mm female spade connector for each of the +/- terminals.
• A pair of wires, preferably in the 18-20 gauge range. I've used a length of speaker wires (as pictured)
• A 10k ohm resistor to act as the internal thermistor, and optionally a piece of metal strip to increase the contact surface area. One leg should be crimped/soldered to the neg terminal.

 

Additional Materials

• I am currently working on a tutorial video. Follow the link here. The video will be made public on May 3rd, 2025.

 

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