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jaminio avatar image
jaminio asked

4kw System with plans to upgrade to 20kw….Multiplus II and will install more panels & battery

Hello

Im new here and to Solar power generation.

I’ve been given a set of 2nd hand 10 year old panels (4kw worth) and a 5kw Ingecon 5kw inverter.

These will be installed soon by a professional installer (when I find one with good reviews). Finances prevent fitting the system I want to use now.


However, I will add a further 16kw worth of panels and a battery bank (we get lots of power cuts).

When I do this, would one Multiplus II 10kva inverter work or would I need 2 - so replace the 2nd hand inverter?
Or could I simply install the extra panels and inverter as a separate system and somehow have them connect as one when supplying the house?

House will be grid connected, but I plan to have grid as backup and run entirely from solar.


thanks



Multiplus-II
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Alexandra avatar image
Alexandra answered ·

@Jaminio

The inverter is sized for your peak loads.

In other words your highest power needs.

For example, I want to run my geyer (has a 1500W element) and iron (2400w) while the washing machine (300w) is on, this needs the water pump (500W). Plus some lights will be on, I can't do it on a 5kVa as my loads will be over 4700W.

I could always switch off the geyser when I am ironing though. ;) And use a 5kVa.

And then dont forget there is a minimum requirement of batteries for the inverter you choose. So the bigger the inverter the bigger the bank.

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jaminio avatar image jaminio commented ·
Ok, thanks for the info.

So the Peak Load is the max power I could be using at any moment (TV, heating/Air Con, oven etc)?

If I were to exceed that load what happens?

Regarding the min req for the batteries, where to I find this? I plan to use Pylontech Force 1.

Lastly, I could get 1x Multiple II 5kva inverter fitted now (instead of using the Ingecon) and then add an additional (or 2) 5kva later when more power is needed correct? is it simple maths (5, 10 then 15kva potential) or do you loose efficiency by having multiple inverters?

Trying to figure all this out so that when I speak with an installer I have some understanding and don't get conned.

Thanks again!

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Alexandra avatar image Alexandra ♦ jaminio commented ·

@Jaminio

The Pylontec Victron guide is here

It is eay though to work out. 5000 (inverter power) ÷ system battery voltage 48v = 104 A.

So minimum is a bank of batteries that can supply this as its continuous (not peak) rating. Obviously you can go bigger.


On an overload the system should shutdown. Will give you warning first though, the time it takes to shutdown depends on how large the overload was over its nominal rating and what model it is.

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Alexandra avatar image Alexandra ♦ jaminio commented ·
You can add more inverters in Parellel to add more capacity but with the complexity of the wiring it is better to have a bigger unit, it is more reliable.

The way around that is to split up the DB board and have an inverter run each section as a completely different system. You would need to add matching battery bank each time you added an inverter anyway and mkre solar for the loads so the cost ends up being about the same.


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