Replace 8kw SS with Blue

What’s all the big ticket items needed?

3 x MultiPlus-II 5000
1 x RS 450/200
1 x Cerbo GX

Lots of odds and sods…

Why do you want 3x5kVA?

Something I’ve wondered about: Is the RS MPPTs necessarily better than the low voltage MPPTs? Depending on the price, it can be swapped for something that is either cheaper or works better given panel placement.

Future proofing so all the MP2’s are compatible with each other.

You can get 2x8kW or just 1x10kW if that should be more than enough?

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The 5kva is the highest for paralleling I believe unless it’s changed.

Ah you are correct according to the datasheets. If it were my decision then, I’d just take one 10kW and be done with it. The more inverters the more problems. :smile:

Victron has a 3-for-2 deal on the 3 & 5kVA until the end of the year.

And that is what I looked at - hectic price! 50k incl for 3x 5000’s - brilliant!

The batts … probably the biggest ticket item on 3 x 5kva inverters.

He has batteries. He’s considering replacing a Sunsynk with a Victron unit. See also other thread about firmware issues. I think he’s fed up and wants to move.

Since I’m the guy who gets roped in every time a parallel system doesn’t behave properly (because it was wired improperly) and then have to very diplomatically tell someone (who wants the entire system refunded because they can’t get it to work) that they have to please check the wiring again… I will also tell people to please just install one single 10kVA unit and be done with it.

Installing parallel systems is advanced work. Not difficult if you know what you are doing, but sadly far too few people fully understand this. Don’t make your first install a parallel install.

There is also a special where, if you buy a Multi/Quattro, you get a Cerbo free. Go for that one :slight_smile:

If you must go with the 5kVA, please read the book “Wiring unlimited”, especially the chapter about parallel systems. And buy a decent clamp meter.

Edit: We’re actually in the process of adding an automatic warning to the system, to notify you if the wiring/impedance is not balanced.


With the current specials, this is by far the best deal available.

You can buy 3 x 5kva for the price of 1 x 8kva.

His got me to assist. I sort of know how this works, and have you as a backup if I forget :rofl: :joy:


One we did last week in Bloemfontein using this config because of the price benefit.

We removed and oldish SMA with optimizers from this site that I need to try and sell at some stage.


I’m glad you’re helping. Very glad. Tempers in South Africa is not the best at the moment, I have to say. Although this also very typical towards year end, in my experience. People are tired, having to ask two or three times (that seems to be more of a Western Cape thing too) gets on your nerves… people have my sympathy.

There are far too many cowboys installing systems, and also installing parallel systems, then leaving the customer with the baked pears. Is that an English expression? I’m making it one :slight_smile:

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Got to be honest - I am very keen to add a MPII 5000 to my system in parallel but my existing is 2.5 years old. So mismatch issues. The prices (R17320 incl) are just so good and I can’t afford the 8 or 10 kw version…

My 5kva runs happily flat out when the sun is good, heating 3kw geysers and powering the house grid-tied.

When the one 3kw element comes on, timers, and the 5.2kw array can carry the load at the time, I run it at 4.8kw to cover the geyser + house loads, and it seldom if ever gives an Overload Warning. Just something I thought, hold on, let’s try this. NodeRED does that for me.

My point is when one gets the panels + batts + inverter matched and you run it optimally in optimal conditions, a 5kva gets you a hell of a long way, if not all the way most of the time.

We, me myself and I have a hell of an argument (blood has flown) going on adding more panels, cause WHEN I need more panels, the main array gives like sub 300w max. So no amount of additional panels will make a dent.

I suspect “Hobby Level” logic is going to be applied …

Just yesterday I sat and thought, so what does one do when you want to add a new inverter, but cannot due to firmware?

So I thought, there is a market for this!

Why does Person A not speak to Person B and make a deal, you buy mine, I buy new, or vice versa, then Person A has 2 x older models under warranty still and Person B buys 2 new ones. Both parties win.

It is all about timing, and some effort.

I was thinking the same thing. But I’m happy with a single MP but 8kw or 10kw would be great.

I did exactly that - swapped an old model for my new model with someone else. But still - follow the good advice. Go for a single unit if you can…

Also agree. Cause if a unit is replaced under warranty and the older firmware models are not on the market anymore, one has a challenge.

This happened to my cousin, 3 x MP, Eskom broke one, warranty replacement, and he had to sell all three. Got himself one big mother MP unit.