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My Inverter%203 2Kw Modbus Register 4545: Back To Battery Source Voltage

Technical documentation for Modbus register 4545 on My Inverter%203 2Kw. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register Back To Battery Source Voltage at address 4545 is used to monitor back to battery source voltage on the My Inverter%203 2Kw.

  • 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 Back To Battery Source Voltage (Address: 4545)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=4545, 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: "Back To Battery Source Voltage"
  address: 4545
  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[My Inverter%203 2Kw]

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


💡 Engineer's Insight

Analysis: Voltage threshold to switch back to battery source, in Volts (V). Defines battery discharge cutoff.

Troubleshooting: Zero may indicate an immediate switch to battery or a fault preventing battery power sourcing.