fgs-energie avatar image
fgs-energie asked

Generator Relay assistant used with grid


how does a system with a Multiplus work if I connect on the AC INPUT a grid and I upload the generator relay assistant to start using that connection at like 20% SOC and finish using it at 80% ?
There shouldn't be the need for a second assistant like ESS or like using a flag, right?

Can it be a simpler solution if someone doesn't want a GX device with the full capability of the ESS ?Thanks,


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3 Answers
Alexandra avatar image
Alexandra answered ·

@FGS Energie

Yes use the generator assistant as the AC ignore assistant, if they dont want to use Vitrual Switch.

You dont need a gx

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JohnC avatar image
JohnC answered ·

Hi @FGS Energie

Yes, you can do this without the complexities of ESS. Instead of switching a relay like you might do to start a genset, you use the 'Ignore AC' in it's place. That's controlled by the General Flag Assistant, so you switch the General Flag, which you define to Ignore AC. Sounds more complex than it actually is to do, but once you have a go it should come together easily.

You'll need to be aware of the state of the AC relay, and make sure you're not switching off when it should be on. If you get tangled up with that, come back..

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fgs-energie avatar image fgs-energie commented ·

Thank you @JohnC for your quick response.

If i got it right, it should be like this and that's it?
This will simply activate the AC INPUT on a Multiplus (now it's just a demonstration using a Quattro) and run the electricity from the grid conncted to it until there are 52V ?

I mean, I really enjoy controlling everything using a Cerbo GX but not every client can afford to spend that money so I would really like to find a cheaper yet satisfying solution for their needs.

Many thanks,



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JohnC avatar image JohnC ♦ fgs-energie commented ·
Nope. You need to switch General Flag. You're not actually starting a genset, you want to switch IgnoreAC. The Gen Asst should actually mention this when it opens. I want you to learn this, but I can produce it for you if you insist.

And having a GX won't do this, it's a Multi/Quattro function.

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fgs-energie avatar image fgs-energie JohnC ♦ commented ·

Alright @JohnC so let me see if I get it:

- general flag user assistant: set it to Ignore AC Input

- gen start and stop assistant: set as above (44-52V)

The inverter works like purely off-grid until a flag is triggered at 44V since the gen assistant kicks in. Then through the grid the inverter charges the battery at 52V. At this point the grid has finished is job and the flag is switched again.

Basically the flag allows the inverter to kick in or out the AC Input by means of the Voltages set in the other assistant.

Did I get it right? It seems a bit complicated by logically correct to me..


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JohnC avatar image JohnC ♦ fgs-energie commented ·
@FGS Energie

I think you're getting it, but you started off talking switching with SOC, and you may find working with V's needs some refinement. You could probably use both with 2 instances of the Gen Asst.

Define the General Flag first. To IgnoreAC.

Then you need to consider that your starting status is having AC on. Usually it's possible to 'Invert' the logic somewhere, so keep an eye out for that. Keep it logical and in order for what you want to do.

If you get stuck on the 'inverting' thing, it's possible to use Programmable Relay Asst to force General Flag. So you can start (and finish) with the status you want.

Once you get your head around how this stuff works, it gets easy. Don't give up yet.. :)

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joker-sk avatar image
joker-sk answered ·

im also trying to set it up like this and according the manual, however, should then in VRM be the generator marked as "autostart" or not?

And secondly, "grid lost" alarm is sounded when the MP is ignoring the grid? why?


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