– is Negative terminal
+ is Positive terminal
tool is for tool to identify the battery
NTC is Thermistor for temperature monitoring
charger is for charger to identify the battery
C1 to C4 is junction between cell groups (for balancing)
Bosch 18V Battery Interface & Pinout Wiring Diagram
– and + = 18V
– and tool = 0V
+ and tool = 18V
– and ntc = 0V
+ and ntc = 18V
– and charger = 0V
+ and charger = 18V
– and C1 = 3.7v
– and C2 = 7.2V
– and C3 = 11.1V
– and C4 = 14.8V
– and tool = ~7 KΩ
+ and tool = 0 Ω
– and NTC = 10 KΩ (25 °C), 4.6MΩ likely measuring across protection circuitry, not directly across the NTC
+ and NTC = 0 Ω
– and charger = ~ 100 KΩ
+ and charger = 0 Ω
