question

Marco Nijholt avatar image
Marco Nijholt asked

Dual Phase 120 on three phase + 0 grid connection (NL)

Hi everyone,

I've been receiving conflicting information regarding the possibility of a dual phase setup on a three phase connection in my home (netherlands). Unfortanately my contacts are of no help so I'm trying here in the community.

Reason being that I run a three phase victron setup with 3x multiplus II (230v 10kva) + Cerbo GX + lynx smart bms + 2x MPPT multi RS + victron smart batteries. But 1 of the multis is in RMA, rendering the system useless. Normally the whole house runs off the victron setup however currently I enabled the bypass switch in my house meaning the whole house runs of the Grid directly.

I have reconfigured the system to run 1 Multiplus II in single phase mode on L1, the other working multiplus II is on L2 but is disconnected. L3 multiplus II is missing due to RMA.

The AC out of any of the remaining Multis are not connected to anything since the load breakers are switched off and the rotary load switch breaker (Hager HIM402 HAG OMSCHAKELAAR 4P 20A MOD.M1) is switched to the grid option.

Here comes my problem. I have 15kwp of solar on the roof, and a 25A grid breaker per phase. This means that i can push around 5750W (+ loads but due to lack of grid meter that is not measureable) out of the single Multi thats running now. In combination with 30kwh this means that on a 80kwh production day or a day where the peak is not consistent due to scattered clouds its just bearely able to push all the PV out without hitting a 100% battery limit. But on days where its just blue skies it will throttle the PV when the batteries are full.

Not even to mention that that single multi is doing 6000W continious for 14 to 24 hours a day. Running at a lower efficiency and more noise and unneccesarily loading the battery bank.

The solution would be to run the 2 remaining Multis, with the multis on L1 and L2 in dual phase 120 mode. Am I correct to assume that what I want can be acomplished by configuring the 2 multis as below? What options for L2 would have to be selected?

1655227912820.png


Theres obvious reasons why you would not want to design your system like this, like drifting away from L3 when the breaker for L1/L2 for some reason trips. Which could result in damaged 3 phase equipment. Aswell as if breaker for L3 pops the three phase devices could be damaged aswell.

But in my case, there will be no consumers on the Multis, they will only be used to deliver the PV back to the grid.


Am I correct in assuming that what I want to achieve is indeed possible, and that its achieveable by the bus configuration in the attached image?

Any other reasons why in my case it would not be recommended to do?


Thank you for your time!


Multiplus-IIESS3 phasesplit phase
1655227912820.png (14.7 KiB)
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1 Answer
kevgermany avatar image
kevgermany answered ·

Seems no one knows. Best check with your dealer

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Marco Nijholt avatar image Marco Nijholt commented ·
Thats unfortanate, victron is not replying to my dealer. And the broken unit got returned with a repaired fuse and they said everything else was ok. However its still broken, the behavior causing the internal fuse to burn out is still there. (pulling 8kw on ac out with nothing connected to ac out).


So I guess i'm stuck with it for a bit.

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