DeWALT 20V Battery Reset: 3 Methods
How to reset a dewalt 20V battery
I would suggest you could use the following 3 methods to reset the dewalt 20V battery.
1) Reset using another healthy dewalt 20v battery
To reset the bad dewalt battery, identify the B+ and B- terminal on the dewalt battery. Connect B+ to B+ terminal and B- to B- terminal. Let them stay connected for around 15 seconds to jump start the dewalt battery.
2) Reset using another 18V or 20V battery from other brands
If you do not have another 20V dewalt battery, you could consider to use another tool battery with voltage range of 18V to 20V. Same step as above, identify the positive and negative terminal of the battery and connect to the B+ and B- terminal of the dewalt battery. I have used a milwaukee m18 battery in this video.
3) Use a DC power supply to reset
If you only have a DC power supply, you could use it to reset the dewalt battery too. Set the voltage to 20V and current to 1A. Connect the positive terminal of the DC power supply to B+ and negative terminal to the B-. It should have reset the dewalt 20v battery.