Paralleling and 3 phase multi's

@JacoDeJongh, You may have some insights here.
I am puzzling over an off-grid 3 phase system design.
I want to standardize on the Multi unit, with a view to choosing the most reliable set-up.

What are the considerations between:
3 x 15kVA Quattros ( 1/phase) or
9 x 5kVA Multi’s ( 3/phase)

Has anyone any anecdotal experiences?

If its completely offgrid, I guess I would personally opt for the 3 x 15kva. Those are beasts and very reliable.}

3 x 5kva will give you some kind of redundency although you would have to reconfigure the system on site should one unit fail.

The pure simplicity of a 3 x 15 Kva Instalations vs the complexity of 9 multies and keeping the AC wiring symmetrical for the three inverters on each phase also tips the scale in favor of the 15kvas for me.


@Phil.g00, if you haven’t yet, please consider the Rs450 series mppt’s, they are true game changers. The 450/200 has for trackers and you can connect over 14kwp it. Rated 18amp max but max 22amp input current per tracker.

Thanks for the tip.
Actually, I have got my MPPT’s ( and PV inverters) already. I have been picking them up secondhand over the last few years. I think I have 7 or 8 (all 150V) for my closer roofs.
I’ll AC-couple PV inverters from roofs further away from my batteries.
Right now I have to ease off a bit because I normally used to travel to SA annually or biannually and I could fill my kids’ suitcases with electronics.
I haven’t travelled for 2.5 years now so I have a weighty stockpile of goods to transport over the next year or two.
The Victron inverters I’ll buy in SA, they are too heavy for suitcases.

You probably get sent for a manual check quite often… :slight_smile:

At least on Schiphol, the automated checking device rejected me over a simple 12V battery charger that was in the suitcase…

Nope, I have been slightly overweight, and I said I was carrying solar inverters to install for people without electricity in Africa, and I wasn’t even charged a fee.
I was just asked if they contained batteries.

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Hahahahah!!! It’s like my one friend that stays in the EU and work that side. Every time when I go collect him at the airport, he climes into the car with two massive duffel bags full of Jap motor parts for his imports. And we talking like big stuff in there. One time he had a full Jap exhaust setup for his MK4 supra in the bags. other time a Intake setup for his skyline and a turbo. :stuck_out_tongue:

Now that is a car I really want. Or maybe even an older MR2 that is nicely fixed up. But man, even the MR2s are fetching crazy prices now. And much as I am a car guy… I don’t quite have enough moolah to be a CAR-car guy, if you know what I mean. I think that is the trouble with having many interests, you can only really spend money on one at a time.

Right now I’m still looking for a Yamaha U1 upright piano, sold by an emigrating soul who doesn’t quite realise what he’s got… but even there, it seems people have wisened up.

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@plonkster will drop you a PM when he is SA, will arrange that he take you for a spin in it. He owns a R34, RX7 fd twin turbo, 2 RX2 capella , the 2 door version. 1975 Celica GT, S14 Silvia and some more other stuff and some really nice Jap bikes that you didn’t get allot of.

I know very little about 3 phase, if it gets to 3 phase my hamster doesn’t even try to stay on its wheel.

Common sense tells me that the 3x 15 kVA Quatro’s in single phase will actually be more redundant than the 3 phase Multi config?
Should you lose a Quatro you are down to 30 kVA and you can simply manage loads for that week or 2 how ever long it takes to get fixed or swopped out.
However should you lose a single Multi in the 3 phase setup you basically have to drop the entire phase since it will be out of balance with the rest. Or I guess you can also switch off Multi’s on the other 2 phases just to balance things out again?

Planning to move to a farm with a 3 phase supply in future, this is something I really have to start getting my head around. As die ouens begin 3 fase dan voel ek sommer dom.

45kW in a single phase setup is too big. That’s almost 200A RMS. It is not a good idea.

One of the reasons for 3-phase is that you get the same amount of power, but with 25% less copper. There are other reasons too, mostly that induction motors become much simpler.

But just watch this… :slight_smile:

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I guess you read the part in brackets the way I did. 1/phase and multies 3/phase.

Initially I also thought phill meant 3 x 15kva single phase but soon realised my mistake.

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Sorry my “/” means “per” as in km/h.

The system will have to be 3-phase, as I want to use motors above 7.5kW.
I don’t think single-phase motors above that are available, or if they are they will cost a premium.
For a lesser requirement, I would recommend sticking to a single-phase arrangement.

Sorry yes, now that I read it again I see my mistake.

I added my second MP ii yesterday. Looking at the HA display, I can already see the benefit. I wanted to add the second MP later this year, but the chances of finding the exact model and the proposed Eskom increase made me do it now.