Dewalt 20v to Ryobi 18v Tool Battery Adapter

Using off the shelf parts and minimal tools to use one brand's batteries on another's tools, while retaining cell protection

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I own a metal fab shop and have invested heavily in the Dewalt 20v and 60v tool lines, including purchasing a large number of batteries as I abhor tripping on cords and sometimes work on the road for extended periods of time.

Recently Ryobi has come out with some tools in their 18v lineup that I wanted to add to my shop, but didn't want to start purchasing new batteries, so I got to thinking about making an adapter.

When DeWalt released their 20v to 18v adapter I knew I could make that work. Lithium Ion batteries need protection from over discharge conditions and after taking apart a DeWalt 20v battery and tool, I found that the protection is in the tool, not the battery. On the other hand, Ryobi retained the same form factor when introducing Lithium Ion batteries so I suspected their cell protection must be in the battery. I opened one and found out I was correct.

I detail the process of building the adapter below and one youtube at 42fab

Once I had determined that the Ryobi 18v tools were just looking for an 18v source and not using any authenticity checks to make sure they had a real battery (as most newer tools do), it seemed like there was nothing standing between making this project a reality other than drilling holes, soldering wires, and a bunch of epoxy.

The only really tricky thing was getting the wires connected as the wires coming off the DeWalt 20-18v adapter and the ryobi battery are rather short, but once that was done, I tested everything and it worked, so I used a good amount of epoxy to attached the 20v/female part of the DeWalt adapter to the shell of the gutted Ryobi battery and it worked.

  • 1 × Dewalt 20v to 18v Adapter Knockoffs work too, but genuine is built better
  • 1 × Gutted Ryobi 18v Battery Found in recycling bin
  • 1 × Heat Shrink Tubing
  • 1 × Solder
  • 1 × Epoxy

  • 1
    Step 1

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