Sungrow SG5K-D PV EVCC modbus not working

[michael-robbins]

Hello!

I'm trying to get EVCC working with my Sungrow SG5K-D PV inverter. It's connected with the comms dongle over wifi, and exposes a modbus interface on TCP/502. There isn't an 'internal ethernet' port or anything on this model.

I'm currently using SunGather to connect at the moment to export all the registers over MQTT to HA (and understand if EVCC is setup it offers a modbus server that this can use).

But it's not working at the moment and I'm not sure why, looking at SunGather it uses a TCP modbus client, but under the hood it looks like Sungrow actually have an encryption layer sitting over the top of the modbus connection.

The above repo uses Sungrow-Modbus under the hood, which does the lightweight encryption/decryption of the modbus packets.

Here's my meter config:

meters:
- name: sungrow_grid
  type: template
  template: sungrow-inverter
  id: 1
  host: 192.168.78.75
  port: 502
  usage: grid
  modbus: tcpip

- name: sungrow_pv
  type: template
  template: sungrow-inverter
  id: 1
  host: 192.168.78.75
  port: 502
  usage: pv
  modbus: tcpip

And here's some of the logs:

laptop:~ $ docker exec -it evcc /bin/sh
/app # evcc meter --log error,modbus:trace -c /etc/evcc.yaml
[main  ] INFO 2024/12/06 13:01:05 evcc 0.131.8
[main  ] INFO 2024/12/06 13:01:05 using config file: /etc/evcc.yaml
sungrow_pv
----------
Power:  read failed: modbus: exception '4' (server device failure), function '4'
Energy: read failed: modbus: exception '4' (server device failure), function '4'

sungrow_grid
------------
Power:  read failed: modbus: exception '4' (server device failure), function '4'
Energy: read failed: modbus: exception '4' (server device failure), function '4'

And the traces:

[sungrow_grid] TRACE 2024/12/06 13:00:58 modbus: send 00 01 00 00 00 06 01 04 13 da 00 02
[sungrow_grid] TRACE 2024/12/06 13:01:06 modbus: recv 00 01 00 00 00 06 01 84 04 00 01 00
[site ] ERROR 2024/12/06 13:01:06 grid power: read failed: modbus: exception '4' (server device failure), function '4'
[site ] DEBUG 2024/12/06 13:01:06 ----
[lp-1 ] DEBUG 2024/12/06 13:01:06 charge power: 0W
[lp-1 ] DEBUG 2024/12/06 13:01:06 charge currents: [0.5 0 0]A
[sungrow_grid] TRACE 2024/12/06 13:01:06 modbus: send 00 02 00 00 00 06 01 04 13 da 00 02
[sungrow_grid] TRACE 2024/12/06 13:01:06 modbus: recv 00 02 00 00 00 06 01 84 04 00 02 00
[sungrow_grid] TRACE 2024/12/06 13:01:06 modbus: send 00 03 00 00 00 06 01 04 13 da 00 02
[sungrow_grid] TRACE 2024/12/06 13:01:07 modbus: recv 00 03 00 00 00 06 01 84 04 00 03 00
[site ] ERROR 2024/12/06 13:01:07 grid power: read failed: modbus: exception '4' (server device failure), function '4'
[site ] DEBUG 2024/12/06 13:01:08 ----
[lp-1 ] DEBUG 2024/12/06 13:01:08 charge power: 0W
[lp-1 ] DEBUG 2024/12/06 13:01:08 charge currents: [0.5 0 0]A 

Any pointers on this? Could it be the encryption requirement on these Sungrow SG inverters modbus comms?

[andig]

I have never heard of modbus encryption. Just ask Sungrow for docs.

[michael-robbins]

Yeah Sungrow added it in a while back circa 2020 for their PV inverters (at least here in Australia, but elsewhere too I'm guessing).

See:

• https://community.home-assistant.io/t/tcp-client-for-sungrow-devices-with-encryption/420918
• https://community.openhab.org/t/sungrow-inverter-binding-or-modbus-config/139360/3

I linked above an implementation in Python of the encrypted wrapper around the modbus requests.

Could that be something that could be worked into EVCC to support these PV inverters?

[michael-robbins]

I've followed up with them (https://aus.sungrowpower.com/contactUS) and will let you know what they say (not holding my breath though)

[michael-robbins]

No real response from them. I'll leave this discussion open as it's still a valid feature request for most Sungrow inverters in AU (and elsewhere where they've added encryption ontop of the modbus layer).

There's at least 1 python implementation out there for this, so it'd just be a matter of reimplementing that in Go.

[andig]

Happy to take a PR. It does unfortunately now scale for the core team trying to duplicate each vendors obscurity efforts. They just have the bigger teams...

[michael-robbins]

Yeah totally fair, I've built something similar to evcc's solar excess charging in home assistant directly atm, but if I get desperate for evcc I'll have a go :D

[andig]

You can still integrate this using a custom meter.

[Lammiwinks]

Same issue for me! Would love this to work <3, Any iodate on your testing @michael-robbins ?

[michael-robbins]

No real update here, I've just built an automation myself in Home Assistant that manages all the EV charging as EVCC isn't compatible with these PV Inverters.

Using SunGather via MQTT I can get all the PV metrics into HA and from there automate everything easily enough.