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matt1309 avatar image
matt1309 asked

Multiplus ii grid and generator

I'm guessing the answer is buy a quattro.

However I have a client that's inherited a small 2kw generator but already has a multiplus ii 10kva ess system which was installed a few years back and they don't have the money to remove the current system to replace with quattro


Are there any more affordable options given its going to be rarely used?

I didn't think a transfer switch on acin with grid and generator as inputs would work due to grid codes set on multiplus for the ess system that's used most of the time. Is there some sort of regulating device I could install on generator so it confirms with grid codes?

My next guess was maybe dc chargers on generator output and go straight to battery. Probably couldn't get one big enough without it being pricey but skyla looks cheaper than whole new system at least, but I imagine I could parallel some smaller ones if it is?


Multiplus-IIESSGenerator
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offroadflow avatar image offroadflow commented ·
Maybe you can program an assistant to stop grid feeding when on generator?

Else the idea to charge the batts directly works too...if the energy does not get fed into the grid...

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Alexandra avatar image
Alexandra answered ·

You can get a grid code to accept a generator if the generator can provide stable power on the input in the grid tolerances.


The real issue is the undersized 2kVa on a 10kva. Usually that is a fiddle even on grid code other with huge tolerances.


Input current limit would need to be lowered to about 6-7A though when used. Or possibly lower depending on generator service condition. This can be done with node red (and then a swap in the GX for the input what the grid input is.)


You are better off though with a dedicated grid/inverter charger. Even a 48v 3kva Multiplus will charge higher than the generator can provide unless turned down. 70Ax48V= 3300w.

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matt1309 avatar image matt1309 commented ·

Thanks @Alexandra


I like that idea. I might give that a test see how we get on. auto transfer switch on ACIN with grid and generator. Then program node red to limit current massively when transfer switch is turned on.

I did try show around for something small enough and struggled.


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derrick thomas avatar image derrick thomas matt1309 commented ·

If you install an ATS you can use a small relay to trigger a digital input set to External Transfer Switch using guimods. You can set separate AC input current limits for grid and generator and the GX device will switch between limits accordingly.

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