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sungrid asked

Consumption on PV inverter AC coupled side - will it work?

Hi, I have a design for this system in the picture. I want to add another system to my existing 3-phase ESS system with AC coupled Fronius on AC-OUT, which is 1-phase and would be connected via ET112 to the AC-IN side. In CerboGX this ET112 will be set up as a PV inverter. But what if there will be consumption behind this meter? Is the system ready for bi-directional power flow for such a connected AC coupling inverter? Will the Multiplus-II charge the batteries from the excess energy from this side and in turn - will the Multiplus cover the consumption behind the ET112 from battery?

multiple-victron.jpg

Multiplus-IIAC PV Coupling
multiple-victron.jpg (347.2 KiB)
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Mike Dorsett avatar image Mike Dorsett commented ·
The main problem I see with this is that the additional power is single phase, and the Multi's won't be able to asymmetrically load the system. However, the concept of adding loads on the pv inverter side of the additional meter is sound.
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5 Answers
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h2009 answered ·

I would recommend swapping out the 1 phase AC inverter for 3 phase.

Remember your AC PV system is limited to the VE Inverters total capacity.

So in my case I have 10kw 3 phase, linked to 30kw 3 phase AC PV solis inverter. Just very limited when looking at adding AC batteries.

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sungrid answered ·

The main problem with the 3-phase AC inverter is the MPPT voltage range. Because this is in a garden, where there are small PV strings, usually 3-5 panels on wood houses, etc., a 3-phase inverter cannot be used. Solax has a single-phase inverter for 220 EUR and is working from 50V.

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h2009 answered ·

I had a similar issue - I've got some short strings with low voltage but I used the AC inverter coupled with Tigo Optimisers (make sure you get CCA and TAP, there optimiser modules with dodgy firmware). Anyway Tigo will allow you to make larger strings in different directions.

My start up voltage is 200v.


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sungrid answered ·

I planning to use Tigo optimizers because of shadow. What is dodgy firmware?

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h2009 answered ·

https://youtu.be/c8KrqmQftRM?si=PPqsstw0p8eODoNA

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