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EW11 RTU-over-TCP fails with current PyModbus / Home Assistant 2026.8 #2

Description

@DrawsACircle

Hi,

I'm trying to use this integration with a Deye inverter through an Elfin EW11 RS485-to-WiFi gateway.

Hardware / software

  • Inverter: Deye SUN-8K-SG05LP3-EU-SM2
  • Home Assistant: 2026.8.0
  • Gateway: Elfin EW11
  • EW11 firmware: 1.50.0
  • EW11 IP: 10.0.0.35
  • Baud rate: 9600
  • Data bits: 8
  • Parity: None
  • Stop bits: 1
  • TCP server port: 502
  • Deye Modbus SN currently: 4

Solar Assistant is connected to the same Deye Modbus bus and is communicating successfully.

RTU-over-TCP

When selecting rtutcp in the integration, setup fails with:

AsyncModbusSerialClient.init() got an unexpected keyword argument 'method'

This looks like a possible compatibility problem between the integration and the PyModbus version included with HA 2026.8.

TCP mode

I then tested transport tcp.

With the EW11 serial protocol set to None (transparent mode), the TCP connection is established and the EW11 shows traffic in both directions.

However, the integration fails with:

Modbus Error: [Input/Output] No response received after 3 retries, continue with next request

followed by:

Modbus Error: [Connection] Not connected[AsyncModbusTcpClient 10.0.0.35:502]

PyModbus logging shows that data is actually received:

Cancel send, because not connected! >>>>> extra: unexpected data:
0x0 0x3 0x2 0xbc 0x0 0x32 0x5 0x92 ...

and repeated messages such as:

No response received after 3 retries, continue with next request

The EW11 status page confirms that the TCP client connects and that data is exchanged between the network and serial interfaces.

My assumption is that the EW11 in transparent mode is passing Modbus RTU frames over TCP, while the integration's tcp transport expects Modbus TCP framing.

rtutcp therefore appears to be the appropriate transport, but that path currently fails because of the AsyncModbusSerialClient(... method=...) error.

Could you please check the rtutcp implementation against the PyModbus version used by Home Assistant 2026.8?

Thanks!

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