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Jk Baterry Modbus Modbus Register 4638: Cell 15 Voltage

Technical documentation for Modbus register 4638 on Jk Baterry Modbus. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register Cell 15 Voltage at address 4638 is used to monitor cell 15 voltage on the Jk Baterry Modbus.

  • Protocol: Modbus RTU
  • Data Type: U WORD
  • Unit: mV
  • 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 Cell 15 Voltage (Address: 4638)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4638, 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: "Cell 15 Voltage"
  address: 4638
  value_type: U_WORD
  unit_of_measurement: "mV"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

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

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


💡 Engineer's Insight

Analysis: Voltage of Cell 15. Units: Volts (V). Represents individual cell health.

Troubleshooting: Potential open circuit, poor connection, or cell failure. Check physical connections and cell performance.