EmsTechLabs Logo EmsTechLabs

Marstekvenus Lilygo T Poe Pro3 Modbus Register 30303: Marstek Battery Wifi Signal Strength

Technical documentation for Modbus register 30303 on Marstekvenus Lilygo T Poe Pro3. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register Marstek Battery Wifi Signal Strength at address 30303 is used to monitor marstek battery wifi signal strength on the Marstekvenus Lilygo T Poe Pro3.

  • Protocol: Modbus RTU
  • Data Type: U WORD
  • Unit: dBm
  • 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 Marstek Battery Wifi Signal Strength (Address: 30303)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=30303, 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: "Marstek Battery Wifi Signal Strength"
  address: 30303
  value_type: U_WORD
  unit_of_measurement: "dBm"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Marstekvenus Lilygo T Poe Pro3]

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


💡 Engineer's Insight

Analysis: Marstek Battery Wifi Signal Strength. Measured in dBm. Indicates the quality of the wireless connection for data transmission.

Troubleshooting: Zero or low signal strength indicates connectivity issues. Check router proximity, interference, and device Wi-Fi settings.