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njordan avatar image
njordan asked

Expand Multiplus II single phase with another Multiplus II.....howto/possible ???

Dear all,
i have an ESS with a single Multiplus II and zero-feedin over all 3 phases. Battery is a 10kWh stack of Pylontechs. Works great but for several reasons i would like to add another Multiplus II for the second phase.

The following questions come up while i'm planning. Thanks for expertise to help me think through it, especially understand how it would work "togehter".

# Regarding configuration. As my Multiplus does also the charging of the battery (not via 48V MPPT charger!!!), how would the two Multiplus coordinate the charging. Like of now L1 provides 35A maximum, would then be the charging load split up 50% 50%...so L1 would be 35/2 A and L2 woudl also have the same 35/2 A. Does the VenusController know that its two Multiplus and organize it by itself??

# In terms of Zero-FeedIn.....if e.g. a load is on L1...of course L1 Multiplus would compensate. The same would happen for L2 (i guess). But how would it work for L3, who of the two would provide the compensation.......or in general both phases would compensate whateve comes in.

Like if L1 = 500W load .........at night L1 from Multiplus would provide 250W and L2 would also provide 250W....

Thanks a lot,

Norbert


multiplus in parallel
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4 Answers
njordan avatar image
njordan answered ·

hey, is anyone please so kind to help me understand my next steps and how this would work technically. Many many Thanks

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Alexandra answered ·

@njordan

I think you don't totally understand 3 phase and parallel power.

In a three phase system, if 250w is on L1. Then inverter on L1 process 250W of power. L2 is on a different phase it cannot provide out of phase power.

In a parallel system not inverters should contribute and are wired to the same point, you do not add loads to one and not the other.

In your post you mentioned 3 phase but have tagged your post as parallel. They are not the same thing.

What does happen is phase compensation (in three phase) which means some phases can charge while another discharges. Zero feed in means no pages feedback to the grid. This only applies to AC PV. If you do t activate DC feed in it does not feed in.

You need to read and watch more information on Victrons ESS attempting a system like this will not have support from Victron if you are inexperienced. Go to Victron professional make an account. And read the manuals.

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njordan avatar image
njordan answered ·

@Alexandra first of all thanks for you reply. sorry for the miswordings, it seems a wording misunderstanding. sure i know what three phases mean and that parallel in terms of electric connection means something different.

Let me try to explain so its not confusing anymore.

If i'm using two MultiPlus2 on only two phases. like L1 and L2. AND my system is a pure charge/discharge setup because other AC inverters do feed into my home. So my Multiplus do zero-feedin and take all overhead that is not used in my household.

Will both Inverters work togehter if its night and my houseinternal load is L1=2000W....means that L1 provides 2000W from Multiplus, OR L1 will provide 1kW and L2 will provide 1kW????


Furthermore, how is the charging done during the day......will both inverters take all "overhead"! that would else run into the public energy network? so again if there runs - 2kW outside my house back to the network and my two inverters would grab this amount. Will L1 take the 2kW and charge into battery or will L1 provide 1kW and L2 provide 1kW into my battery??


Thanks for clarification,

Norbert

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Alexandra avatar image Alexandra ♦ commented ·

@njordan

On a three phase system, if L1 has a load of 2000watts, that inverter on that phase supports the load. L2/L3 won't be contributing to the load at all.

If it was a parallel system (as in two inverters on one phase) then the inverters would share the load.

Do you have AC solar on your home, that why you mentioned feedback? Is it compatible with Victron equipment?

Yes, you can charge on one phase and discharge to loads on another in a Victron system.

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iammotorhomeless avatar image
iammotorhomeless answered ·

@njordan
Sorry, I too am a little confused. I know some houses run 3 phase power. But they wire it so that a third
of the house is on each phase, like this image

1699661428614.jpegis this how you are set up ??

If so, is your single Multiplus II just conected to 1 phase and powering 1/3 of your loads.
lets just say it's on the Red Phase.
You could add a second one to the Yellow Phase.

but the 1st one would still just power the Red circutes and the 2nd one would just power the Yellow circutes.

I have never seen this done, and I honestly don't know if you could connect both units up to the same battery.
Or if you could even control them both from the same Venus Controller, as they would be working as two separate systems



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