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Jkbms Modbus Modbus Register 4140: JKBMS charging overcurrent protection

Technical documentation for Modbus register 4140 on Jkbms Modbus. Data type: U DWORD. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register JKBMS charging overcurrent protection at address 4140 is used to monitor jkbms charging overcurrent protection on the Jkbms Modbus.

  • Protocol: Modbus RTU
  • Data Type: U DWORD
  • Unit: A
  • 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 JKBMS charging overcurrent protection (Address: 4140)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4140, 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: "JKBMS charging overcurrent protection"
  address: 4140
  value_type: U_DWORD
  unit_of_measurement: "A"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Jkbms Modbus]

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


💡 Engineer's Insight

Analysis: Sets the maximum current limit during charging to prevent overheating. Units: Amperes (A).

Troubleshooting: A value of 0 suggests the protection is disabled or not configured, risking battery damage.