Add condition : Stop the generator if production > consumption

Q&A and troubleshooting
, , ,
1

Hi all,

In an isolated site off grid, I would like to:

prioritize the shutdown of the generator when:

  • solar production (PV charger) is higher than consumption (critical load only wired) for more than 1 minute. With a if SOC is higher than 3%.

Restart the generator when:

  • SOC is lower than 3%.

how can I do it in the simplest way please?

I have a CERBO set to Stop/start generator

My goal is not to waste time waiting for the condition: “stopped when battery SOC is higher than” (14% in my case). And reduce battery cycling.

2

Hi pwacquiez,

First thing that strikes me is the SoC of 3 to 14%, I don’t know what kind of batteries you have, but it’s probably bad for their lifespan to stay so low, even for lithium LFP. Battery cycling should be though while designing the system. You should think of your genset as a way to maintain your batteries at an acceptable state more than a “emergency power source” because we usually, we try to work with much higher SoC than you do, better have it not need it than need it not have it :wink:

To answer your question, you can use nodered to make more complex automation, it shouldn’t be too difficult.
Youtube has a lot of ressources about that, and also chatgpt could be a big help with that.

3

The comparison finally works between production and consumption in watts. it was already work for a novice in Node Red. :grimacing: :sweat_smile:

can you tell me how to indicate a physical machine (MP2) to do an action (ON-OFF generator on AC IN) please?

also, I searched in the documents, but I did not find how to merge Node Red with the pre-defined condition parameters in the remote console.
I simplified what I want to do:

If: the solar production (PV charger) is greater than or equal to the consumption of the house (AC OUT 1 on the multiplus2): for more than 1 minute = bypass the SOC condition parameter of the battery

If: the solar production (PV charger) is less than the consumption of the house (AC OUT 1 on the multiplus2): for more than 1 minute = no longer bypass the SOC condition parameter of the battery

4

I know it can be hard when you never interacted with it, but did chatgpt help you in any way?

I’m not sure to understand what you mean by physical machine… if you want to control the relay on cerbo, you can use the “relay control” node, you just have to send a msg.payload containing 0 to open or 1 to close the relay of your choice.

I’m not sure either but if you want to get the pre-defined conditions from the cerbo, you might have to use MQTT requests, but really i’m no expert. There is probably a way to do what you want, but it could be harder than you think if you want to mix the pre-defined parameters with your nodered programmation.

Maybe someone else could help you further but I can’t, sorry my friend.