Jk Rs485 Bms10 Modbus Register 4648: Bms10 cell voltage 21

Technical Definition

The register bms10 cell voltage 21 at address 4648 is used to monitor bms10 cell voltage 21 on the Jk Rs485 Bms10.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: V
• Access: Read Only

How to Read (Python pymodbus)

Use this code snippet to read this specific value via RS485:

from pymodbus.client.sync import ModbusSerialClient

client = ModbusSerialClient(method='rtu', port='/dev/ttyUSB0', baudrate=9600)
client.connect()

# Read bms10 cell voltage 21 (Address: 4648)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4648, count=2, unit=1)

if not result.isError():
    print(f"Raw Value: {result.registers}")
else:
    print("Error reading register")

client.close()

Integration (Home Assistant)

Paste this into your configuration.yaml:

- platform: modbus_controller
  name: "bms10 cell voltage 21"
  address: 4648
  value_type: U_WORD
  unit_of_measurement: "V"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Jk Rs485 Bms10]

    PLC -- "A+ (D+)" --> Device
    PLC -- "B- (D-)" --> Device
    PLC -- GND --> Device

💡 Engineer's Insight

Analysis: Voltage of BMS10 cell 21. Units: Volts (V). Final cell voltage reading in this sequence for monitoring.

Troubleshooting: Investigate open circuits, sensor failures, or a completely discharged/failed cell. Verify connections and cell health.