🔦 DIY Makita Battery Flashlight – Build Your Own Cordless LED Work Light
Sometimes the best DIY projects start with parts that have been sitting in a drawer for years. Instead of buying another cordless flashlight, I decided to build my own using a Makita-compatible 18V battery and some spare electronic components.
The idea was simple: take an old LED lamp, add a DC-DC converter, design a suitable enclosure, and turn everything into a portable work light.
🛠️ Components Used
- 38V LED lamp
- DC-DC boost converter (18V to 38V)
- Makita-compatible 18V battery
- Power switch
- 3D-printed enclosure
- Wiring and mounting hardware
⚡ How It Works
The flashlight is powered directly from a Makita-style 18V battery.
Since the LED lamp requires a higher voltage, I used a DC-DC boost converter to increase the voltage from approximately 18V to 38V.
Before assembly, the converter was calibrated to provide the required output voltage. This allows the LED lamp to operate from the cordless tool battery.
Important: The LED module must have a suitable current-limiting driver. A voltage setting alone does not guarantee safe LED operation.
🖨️ 3D-Printed Housing
One of the interesting parts of this project was making the enclosure.
I used some existing designs from Printables and created additional custom parts to make everything fit together.
The housing holds the electronics, LED lamp, switch, and battery connection in one compact assembly.
🔧 Assembly Process
- Prepare the LED lamp and DC-DC converter.
- Calibrate the converter for the LED module.
- Prepare the Makita battery connection.
- Install the power switch and wiring.
- Fit the electronics into the 3D-printed enclosure.
- Assemble everything and test the flashlight.
The video shows most of the process in timelapse, so you can quickly follow the complete build.
♻️ Reusing Old Electronics
The best part is that the DC-DC converter had been sitting unused for almost 10 years. Finally, it found a useful purpose!
Rather than purchasing a ready-made flashlight, I was able to reuse old components and create something practical.
⚠️ Safety Notes
- Check the LED module's required voltage and current.
- Make sure the converter can handle the LED's power requirements.
- Use suitable wire thickness and insulated connections.
- Avoid short circuits on the battery terminals.
- Add appropriate battery-side protection and a fuse.
- Never leave an improvised battery-powered device charging or operating unattended.
🔗 Useful Links
🛒 12V Battery Charging Control Board – XH-M601