Use Relais of Cerbo GX or Mult

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thomas-k asked May 27, '23

Use Relais of Cerbo GX or Mult

Hi,

i do have a Cerbo GX, managing a Multiplus2 and Pylontech-Battery with help of Smartmeter.

System is up and doing ESS-Job nice eg. take surplus power my seperate PV pumping into Home-system (Yes System is Grid-connected).

At 10am my Battery is already full -> now i like to turn on other consumers...

Cerbo GX does know form Smartmeter that eg. -3000W are consumed = they are pumped into Grid.

I like to set a rule " If total Smartmeter is < -3000W then switch RelaisX ON, ... > -2900W = OFF".

I'm fine to use one of the 2 Cerbo GX relais or the one of Multiplus2... or telling via WIFI eg. to a WIFI-controlled plug would also be fine (not pulling wires is nice).

:) what i do not want to do is to drill into wonderful programming languages or using back-door / jail-break aproaches.

... i did search on this topic... "Generator-Functions seems to work only with positive Powervalues"

Is there maybe an "Assistant" who can perform this mindblowing challange of switching a relais based on available Information, follwoing simple if-then?

Regards,

Thomas

ESS Relay

2 |3000

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Modifications Space

Node Red Space

Answer 1 · 2023-05-27T10:22:21Z

Alexandra answered · May 27, 2023 at 10:22 AM

@Thomas K.

What you want seems simple but is not really possible through simple set up without some programming. You would need to look into node red. It is available on Venus OS large (you tube)

With node red, you can use sonoff or shelley relays to switch loads on and off, so is easy to integrate into wiring. I have not tried smart meter switching, but do it (currently) based on SOC and loads in the house.

So maybe so research on whether your smart meter has a pallet available in node red already? I am not a programmer by any means but have managed. There is so much already freely available on git hub to copy and paste in that really all you need to do is look for what you want there and watch a few youtube videos.

2 |3000

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Answer 2 · 2023-05-27T11:56:48Z

thomas-k answered · May 27, 2023 at 11:56 AM

Hi Alexandra,

thanks for the fast answer!

Seems i have to go into the dirty work of programming in a new language and learning all the strange surprises the victron-base-system holds... no i do not think victron is bad here, just experience tells that all controllers hold wired things.

For me it is strange that victron has not established methods where you can use things which are anyway already present in system. "If then" you learn in 2nd hour of programming, as it is a very very basic need.

I did not get your comment on "smart meter switching" (maybe i phrased my question missleading)...

For me this EM24 smart meter is a Datasource to Cerbo GX, it does decide nothing, only Cerbo GX decides and gives instruction eg. to Multiplus2.

But maybe you meant it in the sense of "using smart meter information for switching"?

Regards,

Thomas

1

2 |3000

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Alexandra ♦ commented · May 27, 2023 at 02:20 PM

I meant I have not used a smart meter information to trigger switching as I don't use a smart meter in my system at all.

But generally using solar production based values as triggers is fairly complex (unreliable) from what I have sort of looked at.

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