Project:DeWalt Battery Replacement
| ProjectInfoBox DeWalt Battery Replacement (NiMH to LiPo) | |
|---|---|
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| Status: | done |
| Release Date: | October 2018 |
| Initiator: | |
| Team: | Johannes |
| Materials Used: | DeWalt cordless drill with broken battery, 3S lipo, a balancer board |
| Tools Used: | soldering iron, 3D printer |
| Software Used: | Fusion 360 |
| Approx. Cost: | approx. 10 € (without the battery) |
A DeWalt_DC740KA Cordless Drill that we used to have had a broken battery which needed to be replaced. In order to replace it, we used LiPo batteries with a custom charging curcuit. In addition to this page, the discussions during the replacement can be read on github.
Once done, you can find the repaired drill on the drilling table again!
Battery Circuit
connections between Battery and Protection Circuit:
Originally, the battery circuit was using a 20A protection circuit:
This was modified in order to support 30A:
The battery case had to be recreated. This was done using the 3D Printer. The files can be found here.
Charging Station
Since the battery got replaced, we also needed a new charging station:
The charging station is nothing special, just a DC to DC converter with constant current and constant voltage (CC/CV). The current is set to 0.5A and the voltage to 12.5V which provides a safe charging process.
Charging Curve: 
Charging: CC red LED
Battery Full: CV green LED
