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thepilot avatar image
thepilot asked

Multi-plus or Quattro

Hi


I'm looking to install a system in my home. Basically I'd like to install a PV array in my garden (field) and start a system that I can expand the size of the PV array untill it is about 20Kw. I'll be using lithium batteries to act as the storage system and again will start small but wish to increase the size of the battery system also over time.

I would like to design the system so that the batteries/solar provide power to the home when available, and when not the grid connection will provide the power.

I'd also like to have 2 AC phases available, I have 2 grid phases available as AC inputs so would like to have 2 output phases to connect to the home setup currently in place.

There will be no feed back to the grid, as we are not able to get this.

Would I be better using a Multi-plus or Quattro for the setup?

Many thanks

Mal

system design
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4 Answers
nickdb avatar image
nickdb answered ·

If you want to connect to both grid and a gennie, get a quattro. If you are only connecting via grid, the multi is fine.

Multi's stop at 10kVA, quattros to 15kVA (in one unit), both can be paralleled or support 3-phase setups.

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klim8skeptic avatar image klim8skeptic ♦ commented ·
Are you sure that the 8-10 kva multiplus's can be paralleled / multiphased?
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thepilot avatar image
thepilot answered ·

Cheers nickdb,


The two phases I have coming in power two sides of a large farm house, I think we could be happy with one 15kva Quattro if it can do 2 phase outs.


One question tho is, if the AC demand is more than the battery can provide will the grid still be able to provide more? What I mean is if the Quattro 15kva max continuous power is 12kw (@ 25c) and the 2 phase demand is 16kw would this be met? I note the peak power is 25kw on this Quattro so is this a hypothetical figure or is that a limited max available?

Just FYI I've never recored us using more that 11kw continuously (thats both phases combined).


Many thanks again


Mal

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nickdb avatar image nickdb ♦♦ commented ·
Grid-attached, the inverter will pass through up to it's input limit which is 100A in the case of the 15kVA and it can power-assist by adding inverter power if grid input is limited.

Each inverter will power one phase, though you could combine both sides of the house into one phase if it is within limits, or parallel systems to get sufficient headroom.

Else if both input phases are required, you would need two inverters, one per phase (common batteries and PV shared between them), in which case you could use smaller ones for each side, but you should ideally use a data logger to measure peak power and daily consumption - nothing worse than getting your maths wrong as it can get expensive to fix.


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thepilot avatar image
thepilot answered ·

Thanks Again,


Yes I was looking at the idea of two smaller inverters, in this case probably Multi's and take one AC input each. I wasnt sure about sharing the PV array between them or sharing the battery bank, I assumed I'd need to double up on the batts and PV for each invertor?

I assume two 8000va Multi's would be more than sufficient, could probably even use 1 8000va and one 5000va given the loads on each side.


I'll go back to the drawing board and start a shopping list!


Cheers


Mal

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nickdb avatar image nickdb ♦♦ commented ·
inverters need to be identical for these setups, unfortunately no asymmetry allowed.

You will need a cerbo/GX to coordinate between all the parts.

Just make sure you size your battery bank and PV sufficiently to supply all the equipment.

There are mppt calculators on the site, but if you are new to all this, I would encourage you to get someone to assist as it can get quite complex and overwhelming in the beginning.

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klandos avatar image klandos commented ·
8000 multis cannot be parallelized, you have to use 5000multis or quattros.
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thepilot avatar image
thepilot answered ·

Cheers Nickdb,

Any idea of whom to chat to regarding this? Should I look for a local installer or would someone on this site be better to talk things over with?


Thanks

Mal

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