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paul-c-olin avatar image
paul-c-olin asked

Multiplus - PV panels at 700V DC at STC.

I am about to install PV panels on a house I purchased.

Depending on the size of the panels and of the installer it will be something like 16 or 18 panels.

The possibilities of the Multiplus II GX seems to suit me well.

Except the DC supply voltage, which goes for 48V DC nominal.

But there is no way to wire my panels in a diagram that suits this voltage, it will rather be a series string od 700V DC at no load STC conditions, or 2 packs in parallel yielding 350V DC.

So, from the Multiplus II GX tech specs, I will have to use the diagram at the bottom right, kind of what's called an AC battery (but with grid a connection).

The sole thing in grey on the diagram is the PV converter (700VDC or so to 400V AC 3f in my case). I did not find any simple PV inverter on the market that does just what their name stands for; they all have battery connections, or balancing stuff etc... all things that are already inside the Multiplus. The only thing that could be included in the PV inverter I am looking for would be a decent MPPT.

Victron does not seem to have such a thing in their catalog (which explains the grey tint ) .

Has anybody any advice on this??


Paul Colin


multplus 2 gx
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Alexandra avatar image Alexandra ♦ commented ·

@Paul C olin

No diagram attached?

Short answer Victron does not have a 700v mppt. Highest is 450v in the RS MPPT range and that is also based on battery float voltage X 8. You can use uneven string on it. So that is an advantage.

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paul-c-olin avatar image
paul-c-olin answered ·

Thanks for answering.

I will have a look at the RS MPPT range.

But what does X means? Seems to say something about the battery voltage?

multiplus-iigx-diagram4.png


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Alexandra avatar image Alexandra ♦ commented ·
The GX means there is a monitoring device inside that can report to the VRM.

You can get the Multiplus II without a GX, and then add a Cerbo as the GX as well.

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