Multiple OpenDTU-OnBattery in a single household

[rradkov]

Currently, I have two microinverters (HMS-2000-4T) installed on the roof and one HMS-1000-2T installed on the balcony. Both are manage from a single DTU, with DLP activated for zero export with Shelly EM.
I want to add 3 more inverters (2x2000-4T and 1x1600-4T) to the existing setup.

The problem is that the garage, where I plan to install the two 2000-4T inverters, is quite far, and OpenDTU won’t be able to manage them. The same applies to the BBQ area (1600-4T).
I have a good Wi-Fi signal in both the garage and the BBQ area. My concern is that if I have three DTUs managing the inverters, it could lead to excessive energy being produced or fed back into the grid.

Is there a way to establish communication between 2, 3, or more DTUs so that they synchronize only when needed, based on consumption changes or are you planning adding this functionality in the future?

[gitisgreat2023]

Which Shelly do you have? If you have one which supports API Gen 2 or higher you have a powerful possibility with the Shelly scripting.

Basically the solution with the Shelly scripting is that it generates several "virtual power meters", which every DTU uses in its feedback loop.
The Shelly gets the current production value of each DTU via MQTT, it measures already itself the current in/export. Then it chops up the overall demand over the different DTU's, each DTU gets then the "virtual power" value presented.

However it will involve some coding in Shelly. And it is not trivial for me currently to make it robust against issues (for example a single DTU cannot be reached anymore). At the moment I abandoned this approach, because of these robustness issues.

If you know how to deal with error handling in modular javascript I'm happy to help you out with the Shelly code.

[rradkov]

Could you please elaborate on the topic?

[schlimmchen]

The problem is that the garage, where I plan to install the two 2000-4T inverters, is quite far, and OpenDTU won’t be able to manage them.

I think you should test that first. If WLAN is fine, the sub 1GHz channel should have no problem reaching the same spots.

[rradkov]

Well the distance between the DTU and the garage roof will be around 40-45 meters. Distance between the DTU and the BBQ will be around 20 meters also.

[schlimmchen]

So? 20m are no problem, I am sure. Even 50m should be totally fine, especially in the sub 1GHz band.