Support for SH25T (or other models that only have a WiNet-S port and no additional internal port)

[chultquist]

Hi,

I'm looking at buying a SH25T Sungrow inverter and would definitely want to be able to control it via something like Home Assistant. However, from the docs I've found (for e.g. page 47 of https://www.memodo.de/media/pdf/a6/3b/cc/memodo-wechselrichter-sungrow-shxt-user-manuel-en_87f641d1f13017d5e4d1c78c5eeddf83.pdf) it seems like it only has a WiNet-S port and no additional internal LAN port.

Does anyone know if Modbus TCP works on these models (either over a wireless or ethernet connection through the WiNet-S port)? Or any tips on how I could find this out?

The PDF I mentioned earlier suggests that Modbus TCP is meant to work over ethernet through the WiNet-S port (see the "LAN function" section on page 69).

A related question is whether it's possible to use the LAN and WLAN connectivity of the WiNet-S for these models at the same time. The docs say "it is not recommended to use both communication methods at the same time", but doesn't say why...

I found #277 where another user indicated they have had success with the SH20T which sounds promising, although not with enough details to answer the questions here.

Thanks,

Carl

[little-penguin88]

Hi Carl,

it does work with the standard WiNet-S2 via WiFi. (I did not test yet but assume LAN would work as well) Just enter the IP of the Wifi adapter which shows up as "espressif" in your router most likely.

However some of the registers seem to be not existing in the SHxxT and some are missing like the 3rd MPPT. But general Modbus TCP connection does work

[chultquist]

Great - thanks @little-penguin88

[Gnarfoz]

The manual hosted by that shop is a bit outdated, the Sungrow homepage has a current one: https://ger.sungrowpower.com/productDetail/3024
It probably doesn't differ in this matter, though. It only has one port, for the WiNet-S2 dongle. The dongle offers WiFi and Ethernet.
Use Ethernet if you can, otherwise use WiFi. What would be the point of using WiFi and Ethernet at the same time?

Apart from that, the SHxT series is covered by the same Modbus documentation as the SHxRT series. Meaning, this project here should work on both. However, SHxT's are still a bit rare, so there's not much user feedback regarding this.

[Gnarfoz]

I doubt that would make a difference. Can you read the register with any other Modbus client?

[little-penguin88]

Ok, this is definitely not what I expected... We are looking for 0x1396 and 0x1397 registers. And you can't read them as single register nor as pair. But if you read also some register before or afterwards with one command it does work....
So reading all 6 Mppt registers and split them would work.

[Gnarfoz]

That's... Super weird and unexpected. 😳

[ahd71]

Observation related to that weird behavior. In HA version 2024.4.0 something changed which caused my data from sungrow to not fully work. While isolating the problem I noticed that some registers that suddenly couldn't be read in sequence was fine read isolated. Later claimed to be resolved but my workaround to remove a bunch of by me unused registered is still on place so cannot confirm.

[Gnarfoz]

Well is there a way in HA to read 12 bytes beginning from 5010 and split it to the 6 INT values to have the MPPT3 voltage and current read out?

Resurrecting this because I just stumbled over it:
The HA Modbus integration actually has such a feature, it's called virtual_count!
It's only available on int/uint/float16/32/64 registers.

It does look like it'd be worthwhile to use this for adjacent registers with identical scan_intervals instead of polling a bunch of stuff one by one.

[Gnarfoz]

@chultquist As pointed out by someone involved in the discussion about @little-penguin88's observations regarding MPPT3, another option would be to (ab)use the "logger" (COM2 A1/B1) ports with an RS485 converter to basically re-gain the dedicated Modbus interface, bypassing the WiNet-S2.

[chultquist]

👍 thanks, @Gnarfoz. Good to know and I'll give that a try once we've done the install if Modbus TCP doesn't work well enough for me.

We're still a month or two off actually getting this installed, so will only be able to come back & confirm then.

[Gnarfoz]

Perhaps there's a new firmware update out by then that makes these registers accessible individually. :-)