The BMS Main 2.1 headers are shown in figure below.

The BMS Main 2.1 headers

Pin | Name | Description |
1 | GND | Ground |
2 | V+ | Supply voltage 9-30V |

Pin | Name | Description |
1 | RS485_A | RS-485 line A for communication with BMS Logic |
2 | RS485_B | RS-485 line B for communication with BMS Logic |
3 | +5V | Supply voltage for BMS Logic |
4 | GND | Ground |

Pin | Name | Description |
1 | +5V | Supply voltage for the current sensor 5V, max 50 mA |
2 | GND | Ground |
3 | Vcs | ADC input (current sensor output) |
4 | Vref | ADC input (current sensor reference signal) |

Pin | Name | Description |
1 | +5V | Supply voltage 5 V, max 50 mA |
2 | GND | Ground |
3 | Vhs | ADC input (humidity sensor output) |
4 | Vts | ADC input (temperature sensor output) |
- P8 – header of relay 1

By default, relay 1 is used to control the discharging contactor.
Pin | Name | Description |
1 | V+ | Switching voltage (up to 55V, max 2A) |
2 | NO | Normally open contact |
- P9 – header of relay 2

By default, relay 2 is used to output the “Allow charging” signal.
Pin | Name | Description |
1 | V+ | Switching voltage (up to 55V, max 2A) |
2 | NO | Normally open contact |