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glipschitz avatar image
glipschitz asked

Fronius AC Coupled to Multiplus II Error

Hi Brainstrust,


I have a Fronius Symo AC Coupled to a Victron Multiplus II


DC PV ---- Fronius ---- AC Out 1 (Victron) --- AC In 1 (Victron) --- AC Load


I have followed the instructions to set the Fronius to MicroGrid 50 mode (https://www.victronenergy.com/live/ac_coupling:fronius)

The Fronius and Victron are on the same Layer 2 segment and have a Layer 3 IP.

The ESS Assistant has been loaded on to the Victron.


When the Fronius boots up, it seems to sync the AC frequency, then tries to take load and trips the Victron.


Running out of things to investigate.

Any ideas?2023-12-06 08.08.01.png2023-12-06 10.44.19.mov

Multiplus-IIAC PV CouplingFronius
2023-12-06-080801.png (361.6 KiB)
2023-12-06-104419.mov (69.5 MiB)
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4 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

How much power does the Fronius Symo have?


Since you have a 3-phase system, the 3 MultiPlus can take up to 12kW, if the grid is not connected or configured wrongly.

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glipschitz avatar image
glipschitz answered ·

Hi @Michelle Konzack

Fronius is 5kW with 6kW of panels.
1:1 factoring is fine for the Multiplus II

Only running single phase here.

I think the issue was to do with the CANBUS communication to the battery causing a current surge and over protection.

Battery manufacturer advised CANBUS A.
Made up a CANBUS B cable and the comms seems to be stable now which has stabilised the comms.

Still testing to occur, but I feel I may be getting closer to resolution here.

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glipschitz avatar image
glipschitz answered ·

My issue seems to be a firmware version on the Fronius.
I'm seeking firmware file fro32071.upd if anyone has it.

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glipschitz answered ·

Downgrading solved the issue.

File attached for anyone who may need it in the future.

fro32071upd.zip


fro32071upd.zip (8.8 MiB)
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