Jk Rs485 Bms10 Modbus Register 4780: Bms10 actual battery capacity

Technical Definition

The register bms10 actual battery capacity at address 4780 is used to monitor bms10 actual battery capacity on the Jk Rs485 Bms10.

• Protocol: Modbus RTU
• Data Type: U DWORD
• Unit: Ah
• 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 actual battery capacity (Address: 4780)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4780, 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 actual battery capacity"
  address: 4780
  value_type: U_DWORD
  unit_of_measurement: "Ah"

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: Measures the current total physical capacity of the battery pack. Units are typically Ampere-hours (Ah).

Troubleshooting: A value of 0 may indicate a new or faulty battery, or a measurement error. Verify battery health and BMS configuration.