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koossch avatar image
koossch asked

Multi RS Dual PV String voltages

Hello,

I have a question about the Multi RS Dual PV setup.
I've read both the specs and the manual but I cannot find the awnser.

https://www.victronenergy.com/upload/documents/Multi_RS_Solar/62787-Multi_RS_Solar-pdf-en.pdf

https://www.victronenergy.com/upload/documents/Datasheet-Multi-RS-Solar-Dual-Tracker-EN.pdf


When connecting 2 sets of PV Strings, do the need to have the same voltages?

For example: if I connect one string with 200 volt and a second string with 112 volt, will this be allowed?


Thank you in advance!

Multi RS
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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Koossch,

Different string voltages are allowed for the dual tracker model Multi RS.

However the minimum start up voltage for the MPPT is 120V DC, so I think one of your strings is too low.

Always a good idea to run your design through https://mppt.victronenergy.com first

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koossch avatar image
koossch answered ·

@Guy Stewart (Victron Community Manager)

Amazing, thanks!!

Just to be thorough, is there any documentation on this being allowed?

Because I have the suspicious that this Dual string support is only in the new 2023 model, right? My model is HQ2232N2UX4 and I am not really sure if this is with or without the dual pv-support

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mvas avatar image mvas commented ·

If it is a DUAL MPPT unit then you can have two independent PV strings.
If it is a SINGLE MPPT unit then you can have one PV string.

Which model did you purchase?
A Single MPPT model or Dual MPPT model?

is there a "schematic diagram" on the front cover of your unit?

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koossch avatar image koossch mvas commented ·

I guess it's the Single MPPT model, but it does have 2 PV String connectors.
Having 'the exact same' product name and only this cover-print being the difference between the old and new model is rather confusing to be honest.


This is the front:

multirs.jpeg


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multirs.jpeg (122.2 KiB)
mvas avatar image mvas koossch commented ·

Yes, sorry ... very confusing.
It is clearly a SINGLE MPPT per your schematic diagram.
You can use those two sets of input terminals as a "Combiner Box" ( ie parallel connections )
The DUAL MPPT unit would show two MPPT units in that little schematic diagram.

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Koossch and @mvas,

Apologies if my early post wasn't clear enough on this on this.

In mid-2023 the Multi RS was revised from a single MPPT tracker to a dual MPPT tracker model.

The single tracker model has this screen print schematic;

cleanshot-2023-07-31-at-173803.jpg

The dual tracker model has this screen print schematic;

cleanshot-2023-07-31-at-173749.jpg


The single tracker model is not able to efficiently operate with different voltages on the PV inputs.


The dual tracker model is able to accept and operate efficiently with different voltages on the PV inputs.


cleanshot-2023-07-31-at-173803.jpg (419.3 KiB)
cleanshot-2023-07-31-at-173749.jpg (454.1 KiB)
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GRIGORIU avatar image GRIGORIU commented ·
Can we find both products for buying or just the new one ?

And is there any catalog price difference between the two versions ?

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koossch avatar image
koossch answered ·

thank you Guy, I do understand now :)

thanks again!

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