Second independent Multiplus possible

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dmq asked Oct 20, '21

Second independent Multiplus possible

Hi,

I have installed a single V MP II 48 3000 on phase 1 (AC IN) of a 3 phase AC system. The system is connected to two Solar Charger and a Pylontech Stack.

Is it possible to connect another V MP completly indenpendent from the 1st installation (own GX, own Battery) or will they identify / interfere each other?

Thanks in advance,

dmq

Multiplus-II multiple inverters

2 |3000

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Answer 1 · 2021-10-20T18:50:45Z

Alexandra answered · Oct 20, 2021 at 06:50 PM

@dmq

If you are running it as a stand alone system with all its own associated devices it will be fine.

It really also depends also on how you are wiring it into your DB board as well.

If it is on another phase completely feeding other loads that is fine.

Needing to program for three phase or split or parellel systems implies (that there is a need) that all units are feeding what is classed as one load electrically and so need to be synchronised.

2 |3000

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Answer 2 · 2021-10-20T19:34:25Z

dmq answered · Oct 20, 2021 at 07:34 PM

Thank you @Alexandra - in my case I would like to feed in to the same L1 phase and the loads are also the same as in the first installation. Is that an issue / problem (beside of the "Schieflast")?

Another option I am thinking of would be to connect the 2nd installation to AC Out 1 of the 1st installtion - would there be an issue regarding regulating the power-generation of the 2nd MP by i.e. shifting the frequency? The 2nd installation should be much smaller MP 12/500.

Thanks again.

6

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shaneyake commented · Oct 21, 2021 at 03:51 AM

Having the second setup on the output of the first is called cascade. This is not supported by victron at all. It is possible to do but a lot harder than it is probably worth.
I have done something similar but wouldn't recommend it. There is so many edge cases where something will go wrong. The second unit does not understand the frequency shifting. You have to implement your own control system to get it working reliably.
https://shaneyake.blogspot.com/2021/09/micro-grid.html

So for having them on the same phase but not cascaded that is totally fine and will work. If you need to do zero feed-in that becomes harder.

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shaneyake shaneyake commented · Oct 21, 2021 at 06:05 AM

To clarify you can not connect the outputs of the Mult's together when they are running as independent/stand alone. You would have to split your loads so that each inverter is only powering some of the loads.

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dmq shaneyake commented · Oct 21, 2021 at 06:09 PM

Thank you @shaneyake - I can not access "your" (?) blog post (I am confronated with a google login) - but your hints help me.

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shaneyake dmq commented · Oct 21, 2021 at 06:19 PM

Sorry, Here is the correct link https://shaneyake.blogspot.com/2021/09/micro-grid.html

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Matthias Lange - DE ♦ commented · Oct 21, 2021 at 05:02 AM

If they are on the same phase on the output and supplying the same loads you have to program them as a parallel system.

https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

In that setup you can only have one GX device and the Multis should/have to be on the same battery.

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dmq Matthias Lange - DE ♦ commented · Oct 21, 2021 at 06:10 PM

Thanks Matthias!

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