Tool Battery Adapters with Blinker Board

Note: As with any electronics project, please do your research on best practices and follow all safety procedures. :)

These tool battery adapters allow you to power many different electronic devices with your power tool batteries. The battery adapters come in 3 versions to fit the Milwaukee M18, Makita M18 and DeWalt M20 style batteries:

Milwaukee/DeWalt battery adapter

Makita battery adapter

Great for making anything you want portable (within reason). I made a portable floor lamp and a portable essential oil diffuser. Both can be easily carried around the house and used in areas where we don’t have available outlets.

The floor lamp was simple. I just replaced the bulb with a DC light bulb and connected the power cord to the Milwaukee battery adapter. I then screwed the battery adapter to the wooden base of the lamp.

For the diffuser, I used a DeWalt battery adapter. This one took a few extra steps but was still pretty simple. Since our diffusers run on 24 volts, I needed to use a boost converter to up the voltage a bit.

These are very popular with our Amish neighbors and are most often used to power their diffusers, run buggy lights, lanterns and charge headlamps, phones etc. These adapters have a small “Blinker Board” on the underside. This device keeps the battery from over-discharging. When the battery reaches about 16 volts, it will blink 2 times and then stay on for 4 or so extra minutes. Then it blinks 5 times, stays on for about a minute more and finally shuts off. The blinking is designed so that when you are using these for lights, you know when to get another battery ready (this is especially important for the buggies around here, since when they are out on the roads at night, they can be almost invisible without their LED lights).

It is also possible to have the battery just shut off when it gets low and not blink at all. Do this by bridging the two triangle solder points (SP2) on the board.

Blinker Board specs

Max draw 4 amps

P1 = positive [+] wire in (from battery)

P2 = positive [+] wire out (to device being powered)

P3 = negative [-] wire in (from battery)

P4 = negative [-] wire out (to device being powered)