If you use power tool like drill, impact driver, impact wrench…you must be very familiar with brand like DeWALT, Milwaukee, Makita, etc.
I own several pieces of DeWALT tool, mostly 20V.
There could be different types of DeWALT 20V battery, XR, non XR and Flexvolt.
In this post, I use a normal type of DeWALT 20V battery to create the pinout wiring diagram of this battery.
B– is Negative terminal (Overall negative terminal, no junction terminal)
B+ is Positive terminal (Same, overall positive terminal)
ID is for tool to identify the battery (I believe dewalt tool or charger would read this pin to get its resistance value to know what type of battery it is being connected)
TH is Thermistor which used in temperature monitoring, the dewalt tool or charger won’t work if the thermistor resistance value is not within the acceptable range.
C1 to C4 is junction between cell groups (There are 5 cells connected in series, each cell must be charged in balance)
DeWALT 20V Battery Interface & Pinout Wiring Diagram
For my battery measurement this time, I only use a low capacity dewalt 20v battery (2.0 Ah).
It only use 5 pieces of 18650 battery cells connected in series to give the total output voltage of 20V.
I also used a digital multimeter to measure the voltage and resistance value between the pins.
Here are the data I measured from the DeWALT 20V battery.
B+ and B- = 20v (Overall positive and negative terminal)
B+ and TH = 0v
B- and TH = 20V
B+ and ID = 0V
B- and ID = 20V
B- and C1 = 4v (One cell, 4V)
B- and C2 = 8V (Two cells, 4V+4V)
B- and C3 = 12V (Three cells, 4V+4V+4V)
B- and C4 = 16V (Four cells, 4V+4V+4V+4V)
B+ and TH = 10KΩ (25 °C), ~8KΩ (Current Temp) When I measure the thermistor resistance value, it shows only around 8KΩ, which is due to to my room temperature that time. I believe it is a thermistor that would read 10KΩ when at 25 °C, which is a common thermistor type for most of the tool battery.
B- and TH = 0Ω
B+ and ID = 0Ω
B- and ID = 1KΩ – DeWALT tool or charger would read this resistance to know which type of battery it is connected to. For example, the dewalt tool or charger know it is connected to a normal and original DeWALT battery when reading this pin. If fake dewalt battery is connected to the tool, it might not have this ID pin, or this pin does not read 1KΩ and the tool or charger could refuse to work as this is not a recognize original dewalt battery.
Here is the top view of the DeWALT 20v battery.
The model of the battery is labeled at the bottom of the battery.
This is a DCB203 model of dewalt battery.
Also, there is a date the printed in the battery to show the date it is being manufactured as shown in the image above.
There are 2 rows of pin (middle parts), the lower row are the junction cell pin for charging balance as mentioned previously.
I removed the battery cover and put them side by side so that you could see it clearly.
The big red wire is the positive terminal while the black big wire is the negative terminal.
If you are interested to reverse engineer the dewalt battery, you could get more details about its battery management system.
