question

Ahmed Abdelgawad avatar image
Ahmed Abdelgawad asked

parallel 4x15k Multiplus

Dears,

i am sizing an offgrid system to feed load: 10KVA for 24Hr

my proposal is:

4 x Multiplus [48/15000/200-100] connected in parallel

each of them is connected to:
1x 24 battery 3890AH [c10 3080]


i need to connect solar PV modules[66,600Wp) and ongrid inverter (fronius) as AC coupling with Multiplus

so i connect them as

4x ongrid fronius symo inverter 15.0-3-M[15KVA] each will have 2x15 PV modules 555Wp [16,650Wp]

to match 1:1 factor of Ac coupling


is this configuration right? is there any concern i should be aware of it?, is there any optimization? [ex: connect 66.6KWp solar to higher capacity inverter]


Appreciate your support

multiplus in parallel
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matt1309 avatar image matt1309 commented ·
Someone correct me if I'm wrong but I didn't think the Mutliplus 15kva worked in parallel?

I think you'll need to use Quattro for your setup, but I'm not 100% on that.


I'm not too familiar with Fronius inverters but is the one you mentioned three phase? If so, the only other part I'd flag is so how are you planning to configure the system to work with three phase ie with 4x15kva quattros/multiplus?

I think you'll need a multiple of 3 inverters to use the three phase inverters off grid rather than 4.


(PS Very jealous of you designing a large system)



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nickdb avatar image
nickdb answered ·

8 - 15K Multi 2's only support 3-phase configs, not parallel.

So you will need to use Quattros.

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Alexandra avatar image Alexandra ♦ commented ·
Add some DC mppts as well. You will thank me later...
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Michelle Konzack avatar image Michelle Konzack Alexandra ♦ commented ·
Hi Alex,


I say only ;-)


Last year I have done this at a new customer too, after his 45kVA (3-Phase) went offline because of an empty battery.

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Michelle Konzack avatar image
Michelle Konzack answered ·

Some comments:


1) I would use 3 smaller batteries and each connected to a custom made power rail with a H01N2-D 95mm² (if not 120mm²) because 15kVA Inverter has a current of 312,5A and you will run into trouble if you use only a singel battery.


The H01N1-D 70mm² support 341A in duty cycle S1 but it become very warm.


2) no, you can not use the Fronius Symo because it is made for 3 phases.

Use the Fronius Primo instead


3) I hope, you know what you are doing, because a custom power rail must be well designed, especially if you push up to 48kW or 60kVA over it. If the voltage goes down to e.G. 22V, then you have to handle a current of 2730A without overload. The biggest Copper rail you can get series is 200x10mm and it support only 2200A... I hope you know what dimension this is.


I currently in a design phase for 12 15kVA Quattros and have to bolt 2 or three of this copper power rails (each is 4m long) together, use NH3 fuses, 8 battery sets of 48/4350Ah (give in total 1600kWh) and use H01N2-D with 120mm²...


I have to handle more then 6000A @48V.


And as I sayed already:

I hope you know, what are you doing!


Have a nice evening.

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