jeibre avatar image

3-phase 230V

Reading the manual for Multiplus 2 and the appendix for three phase connection, it seems that it describes a 3-phase 400V grid (L1, L2, L3, N and PE). In a 3-phase 230V grid (L1, L2, L3, PE), what am I doing with N? And do I still need three Multiplus 2 to feed back to grid in 3-phase?

Multiplus-II3 phase
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5 Answers
Paul B avatar image
Paul B answered ·

you have to have 3 phase and Neutral for incoming power and you get 3 phase and Neutral out from the inverters

If you want full 3 phase control then you need 3 x multi/Quattro inverters

you can connect PV to a single phase, but the outputs from the pv would only go to that one phase's electrical loads. There are a few diferant ways to do this Grid Tie or MPPT direct to the battery

for that matter you could just put one inverter in on one phase and run all the single phase stuff off that one inverter. and the PV only to that phase as well

ONE battery bank is used for all the inverters and the MPPT regs that charge the batteries from the solar are the most efficient way to go. usually they are around 15% more efficient then Grid Tie inverters. as these convert DC to AC then you convert AC to DC to charge the Batteries then convert DC to AC again. lots of overhead in the type of situation

using direct battery charging is DC directly to the batteries (with small MPPT loss) and then DC to AC only one step to the loads

Most inverter and Solar configurations can be setup and catered for,

The agent you are buying the gear from would be able to advise the best setup to suit your situation

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jeibre avatar image
jeibre answered ·

Thank you for answer! First: I have one battery bank and MPPT regs to charge it directly from PV. Good to see that you recommend that! But what you say about 3-phase, does it mean that we can not establish a 3-phase system here in Norway? We have a 230V IT grid which supplies the house with 3-phase L1, L2, L3 and PE. Taking out current between L1-L2, L1-L3, L2-L3 for the different loads in the house. Or is it possible to divide PE to create both PE and N from PE?

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As far as I know this is not supported, but let's call in the man who knows for a Victron answer:

@Johannes Boonstra (Victron Energy Staff) help!

Is it possible to connect like this in principle? (Will not connect double wire in MP, but use separate cables (3 x 2) all the way from the grid to MP)

img-0628.jpg (1.7 MiB)

No you don't want to do that.

When the unit's go into inverter mode the Neutral will be connected to earth.

Every Manual will tell you the units are not suitable for Delta connection. I don't know what will happen in practice, but I wouldn't want to try it...

I don't know if other brands support this wiring, is it possible to change the house wiring to 1 phase? or would that overload the grid connection? this way you could work with one (bigger?) inverter.

It is maybe possible to use a transformator 230v-400v and in that way create a 3-phase 400V grid in the house. But will the Multiplus then be able to feed back to the main grid through the transformator?

I don't think that should be a problem, but please check with official Victron support and an electrician if changing the house wiring has any consequences.

It shall not be easy... A trafo uses about 5-6kwh a day, more than I will feed back. Have to forget that solution.

But we are thinking about an other. What if we use the connection I sendt you at AC in, but separate the AC out by not connect the Multiplus AC out together. That give us three different singlephase-systems on the loads that of course must operate independent of each other. It should not be any problem with connect the battery to all three at the DC-side and as singlephase system, each of the Multiplus can feed back to their own phase. Even with the restriction of feeding back at 16A per phase, I can feed back 16A to each phase and like that get the most out of my 7KW at the roof in sunny days.

The connections on AC in, should in this case in principle be the same as me and 2 of my neighbour connected one Multiples each to the grid phases L1, L2, L3 and Ground. That will of course be allowed.

If this work out, it is stille some question about the Venus. I suppose you neither can connect one Venus fram Multiplus to Multiplus. But Venus have 5 direct contacts and i hope it is possible to connect each Multiplus one by one to these.

I understand that this solution has to be examined by Victron staff, but want to hear your opinion.

I don't know.
What I do know is three separate 1 phase systems on one Venus device does not work, you can only use ESS on one of the systems.

Hi again and thank you for being patient with me! Have made a connection plan of my system. I understand that I can not monitor ESS on Multiplus 2 and 3. And maybe there will be som problem with charging the battery, since only Multiplus 1 is connected to Venus?

How to get answer from a Victron staff?

3-phase-1-phase connection Lykkebo.pdf

PS: As you see, I have made some small changes in the connection plan to day, monday

I also have the same problem.

Any solution? Which country?

no, Norway.

As i thought. Me too... Hva med en prat på norsk via tlf. Nås på 95843309.

lassestu avatar image
lassestu answered ·

Any Victron staff that can answer this question? Three Phase 230V-IT (Delta) (230p-p) systems are common in Norway, only new installations use 400V TN-S (400p-p, 230p-n).

I see many gridtied inverter have the IT options on three-phase systems, why dont hybrid inverters have the same options? If it is for voltage measurement, can't PE be used for a common 0V reference?

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It is already answered in the manual: not possible.

so the only way is to use one or more single phase systems, or use a transformer to create a real 3x230V+N system.

there is a reason why these systems are not longer installed, and in many places they are replaced already. (In the Netherlands some regions had this also).

carl-dewever avatar image
carl-dewever answered ·

As far as I know 3-phase delta grids exist in 4 countries :
- the Netherlands although only a small part of Amsterdam

- Norway

- Taiwan

- Belgium

The only inverter company which supports Delta-grids as far as I know is Solaredge. You can even switch their inverter from Delta(3L-P) to Y-grid (3L-N-P) if at one point your grid provider decides to convert from Delta to Y-grid.
Then again, they only support Delta in their range of normal solar inverters, not in their range of StoreEdge inverters which you can DC-couple to a battery system.

I'm very sad to read that Multiplus-II-inverters don't support delta-grids as this makes using Victron for my ESS-installation impossible.

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Germany is 3 phase to the house, but that's the limit of my knowledge
Alexandra avatar image
Alexandra answered ·

@jeibre @lassestu @Carl Dewever

On the Where to Buy page, there are listed Dealerships and Suppliers for almost everywhere.

There are quite a few in Norway, Belgium. Since they exist I imagine the product still has its uses. People who live/ work with these types of systems would be more qualified to answer how they manage to install Victron 3 Phase systems under these conditions. Most of the world uses Neutral Ground connections even in backward Africa.

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I would not call Africa backward but yes, most countries have a neutral ground wire. This is called a 3-phase star-grid.

And parts of Belgium have them this star-grid but a large part of Belgium still has a 3-phase delta-grid