– is Negative terminal
+ is Positive terminal
TH is Thermistor for temperature monitoring
C1 is junction between cell groups (for balancing)
Pin 1 to 7 is for makita tool to identify
Makita 18V Battery Interface & Pinout Wiring Diagram
– and + = 18V
– and C1 = ~3.7V
+ and Pin 1 = 0V
+ and Pin 2 = 18V
+ and Pin 3 = 0V
+ and Pin 4 = 18V
+ and Pin 5 = 0V
+ and Pin 6 = 18V
+ and Pin 7 = 18V
– and Pin 1 = 18V
– and Pin 2 = 0V
– and Pin 3 = 18V
– and Pin 4 = 0V
– and Pin 5 = 18V
– and Pin 6 = 0V
– and Pin 7 = 0V
– or + and TH = should be 10 KΩ (25 °C)
Why read ~0 Ω?
TH is tied to pack negative (or positive) in the Makita design. Some manufacturers route the thermistor (TH) return to the pack common (often NEG). If the TH terminal is a direct connection or shorted to that return on the pack PCB, a multimeter will read ~0 Ω.
+ and Pin 1 to 7 = 0 Ω
– and Pin 2 = ~235 KΩ
– and Pin 4 = ~305 KΩ
– and Pin 7 = ~230 KΩ
– and Pin 1, 3, 5, 6 = 0 KΩ
TH and Pin 1 to 7 = 0Ω
