9-pin laptop battery connectors carry multiple voltages, ground references, thermistor signals, and SMBus communication for smart battery authentication and capacity reporting to the laptop motherboard.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | V+ | Battery positive high voltage | PWR |
| 2 | V+ | Battery positive | PWR |
| 3 | ID | Battery pack identification | I/O |
| 4 | SMB_CLK | SMBus clock for smart battery | BUS |
| 5 | SMB_DAT | SMBus data for smart battery | BUS |
| 6 | GND | Ground | GND |
| 7 | GND | Ground | GND |
| 8 | THERM | Thermistor temperature sense | ADC |
| 9 | GND | Thermistor ground | GND |