Hi all, The Venus OS supports the integration of PV inverters via TCP Modbus if the PV inverters support Sunspec. I have two suggestions for this that offer additional benefits and, according to my research, shouldn’t require too much development effort. Feature Request 1 Support for Sunspec PV inverters via Modbus RTU The logic can remain exactly the same. Only the underlying connection changes from Modbus TCP to Modbus RTU. Feature Request 2 Support for Sunspec starting at register 50000 Currently, the Venus OS starts searching for the Sunspec header via TCP Modbus starting at register 40000. However, there are devices that implement Sunspec starting at register 50000, which is acceptable according to the Sunspec standard. What do you think? Thanks Dabbelju

Kan het zijn dat de Sunspec regeling geen rekening houdt met max grid-feedin? Edit: Sorry for the Dutch, I added English below: Can it be that the Sunspec management ignores max grid feedin?

I had an (experimental) setup with a Sunspec-compliant inverter on AC-out. It was correctly discovered by GX. PV management and communication was verified by me by using Node-Red (PV inverter / Power Limit) as well as playing around with the Grid setpoint. But I noticed that the PV is not adjusted downwards to comply with my settings/ESS/Maximum feed-in. It also did not adhere to the limit (amps) set in Settings/ESS/Peak Shaving/Maximum system export current (per phase). It was my first attempt to have a Sunspec inverter being managed by GX-device, so maybe I did something wrong?

@mpvader Basically I do agree. On the other hand, most TCP Modbus sticks, or even those via LAN, do nothing more than convert RTU to TCP Modbus. I’ve seen some implementations where the STCP Modbus interfaces represented a bottleneck. It’s certainly not Victron’s job to solve the manufacturers’ problem. Perhaps it’s still worth considering.

Has anyone experience with connecting a Sungrow Inverter? It’s a SG10RT with WiNet-S LAN Dongle.

Where, in Node Red, did you find the “limit calculated by venus OS”? I couldn’t find it myself.

Hi, it is part of the Victron PV Inverter Node. [image] [image]

Hmm, not here: [afbeelding] Nevermind, don’t want to hijack your topic

mhhh MQTT does not sound like sunspec modbus tcp connected inverter. Anyhow…if limiting is supported it needs to be enabled for the inverter in question. And also a Limit needs to be configured in ESS to make the limit calculation work. [image][image]

Ah, it must be modbus connected. But then VenusOS already manages the power limit, doesn’t it? Why setting the limit youself, too?

Support of Sunspec Inverters via Modbus RTU and extended Sunspec Support

Beta testing Venus OS beta testing

Desperado 14 November 2025 17:31 19

Hmm, not here:

Nevermind, don’t want to hijack your topic

House Consumption shows 0 W after adding Huawei SUN2000 to Victron ESS

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Support of Sunspec Inverters via Modbus RTU and extended Sunspec Support

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