Real-time dynamic feed-in adjustment from Victron Multiplus II using Node-RED and MQTT

Modifications
, , ,
1

Hi everyone,

I have a Victron setup with a Multiplus II, Cerbo GX, and 42 kWh of battery storage. Most days, my batteries are fully charged before 1 PM, and I often have excess solar production.

I’m exploring the idea of compensating a neighbor’s consumption by injecting exactly the amount of power they are using at any given moment — even if that means drawing from my batteries when there’s no sun. I would place a consumption meter at the neighbor’s house, which sends real-time data via MQTT. Then, using Node-RED on the Cerbo GX, I would dynamically adjust the feed-in power to match their current load.

Technically, I know Node-RED can control the feed-in level. But I have three main questions:

  • Is the Multiplus II designed to handle rapid, continuous changes in feed-in power?
  • What is the response time between a Node-RED command and the actual change in output from the Multiplus?
  • Is anyone using a similar setup, and are there known limitations or best practices for this use case?

Any insight from others who’ve tried something like this — or understand the technical limits of Victron’s feed-in control — would be greatly appreciated.

Thanks!

2

the ESS assistant for the Multi is designed to handle continually changing power levels. However, Power changes should not be rapid as this can lead to system instability.

3

Thanks for the feedback.

Due to the power meter limitations, the neighbor’s consumption value will be sent about every 5 seconds so I don’t think this is a problem in terms of power exporting changes, right?

Still I can get a good result as our grid, in Portugal, imposes that the real consumption is the difference between importing/exporting calculated on quarters (15 minutes).

Now, when you say:

Power changes should not be rapid as this can lead to system instability

The “rapid” here is how fast I require changes or how big I request them (e.g.: change from 500W to 3kW)?

4

Yes, the key to system stability is limiting the rate of power changes, and if you are connected to the grid, this is normally limited by the grid code standard. updates should be in the order of about 20s min, and changes limited as required.