question

Porcini avatar image

Unbalanced load in a 2x Multiplus II 3000/48 system (Germany)

Hi there!

The new Multiplus II has anti-islanding and a lower standby-consumption than the classic one at the same price (I hope it will be the same quality anyway ;)). But it is only available as a 3000VA Version. In an ESS-system this normally would be enough to providie enough power for the most devices, e.g. a washing machine. Unfortunately if you strive to get 100% self consumption in summer you can only use one device at the same time. So in an average household you need at least two Multiplus II if you don't want to turn the lights or TV off when the washing machine is running.

There are countries with a monophase utility grid like some areas in Italy, which would make this easy. But there are also countrys with a 3-phase grid utility like Germany.

Now in Germany and other countries the maximum unbalanced load of the phases is allowed to be 4,6kVA. Btw: Is that why there isn't a 5000 Multi II, yet?

I have one question about this "problem".

(How) can I provide 4,6kVA to all three phases with the ESS without buying a 3-phase Multiplus 5000 system with external anti-islanding? I think (but don't know) that 2 parallel MP3000 aren't allowed in only one phase, although that would be the best and cheapest solution with an energy meter and phase compensation. When using a 3-phase 3000-System and there is a load of 4000W on L1 - what happens? Two parallel Multi II could cover this to 100%, no matter on what phase it is needed (when having the correct power meter). But is it allowed?


If it matters: there would be a 20kVA-Fronius-Symo-3phase-Inverter at the AC-In of the Multis (because of the 1:1 rule) and a small 1,2kWp DC-Victron-MPPT.


Thank you very much!


regards,


porcini

MultiPlus Quattro Inverter ChargerMultiplus-IIESSEnergy Meter
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1 Answer
Guy Stewart (Victron Community Manager) avatar image

I admire the thought you have put into this.


The new design of the Multiplus-II will make its way across the line up. Almost nobody wants it faster than me! The 5 kVA is in great demand, other models will come with time.


The only way to provide balanced three phase output is with a three phase configuration of 3 multi's.

However the phase compensation feature is sufficient for most cases.

There is a good description of the phase compensation behaviour across phases here:

https://www.victronenergy.com/live/ess:design-installation-manual#phase_compensation_-_further_information


Actual approvals of specific configurations, in specific locations is a question that cannot be answered here. This is for a local distributor to work out with you and the approving authority.

Besides all this, your significant AC-in PV Solar should mean that even if the multi cannot push 100% to the loads in ESS from DC, any extra in daytime will likely come from your solar array.



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Thank you for answering that fast! Really like the new platform. I think I am "almost nobody". I am very interested in the 5kVA-model. These would fit perfectly in a 3-phase system. Can you please tell me roughly when it is proposed to launch? Is it 3 months, 6months or rather 1 year? A few months would be okay for me, but I can't wait for a whole year unfortunately.


regards,

porcini

More than 3 months and less than a year sounds very reasonable. But I have no insider information or control over these matters, just educated and wishful opinion based on what I have seen.

Thank you for the feedback on the platform, please contribute where you can to answer others questions. Already today there is more than I have time to answer, and ideally people don’t have to wait too many days.