Fronius Image


Fronius Ohmpilot in a Victron environment


I am rather new to Victron and a young user of Victron. Have my setup at home gathering everything together.
3 x Multiplus II 5000
1x MPPT RS 450/200
1x Cerbo GX
and a Modbus EM24 Smartmeter

My main question is I would love to use the Ohmpilot to heat up my boiler. But the question is if I somehow get this setup going via Modbus on the Cerbo GX. Or if I need something else to get it going.
Your help is very much appreciated. Many thanks, patrik

ppr asked
ppr answered ·

4 Answers

Fronius Victron connection


I am in the process of designing an off-grid solar household system. I would rather start small with good modular components than go big and cheap. I am currently looking at a Fronius Primo 8.2 running of 30 x 360W Canadian Solar panels at 48V. This will then be connected to either a 5Kw Quattro or 5kw Multiplus (advise on this choice will also be appreciated) to charge 2 x 9,6Kwh Pylontech battery banks (19,2Kwh at 48V). I am looking for wiring diagrams for such a system and advise on any peripherals that will be needed. Can I connect the 8.2 Fronius to the 5kw Victron? Where will my PV power be delivered? If I generate 8.3kw through the Fronius and dump everything into the 5kw Victron will I loose the extra 3.3Kw? Could this be remedied by using the double AC in options on the Quattro? There seems to be limited information on this type of paring on the net and any advise or guidance will be greatly appreciated.


archman asked
paulcupine edited ·

2 Answers

Fronius Symo GEN24 on AC in ESS

I have a question regarding on how I need to set the ESS if I have a Fronius SYMO GEN 24 on AC IN and Fronius can export to grid but Victron should not export to grid but it should be able to give power to local consumption. Thanks!

Robert Boerescu asked
Robert Boerescu answered ·

2 Answers

AC Coupled system


In the latest (Venus OS 3.00) does the following change-log statement refer to the AC coupled side or DC coupled side on an off-grid system for example?


Fix bug where PV was not used for loads when scheduled charging to 100% during daytime



Dave Rae asked

0 Answers

Why combining Fronius with Victron?


I'm talking with a company to install a 3 phase system, solar + batteries, ESS, using 3 Victron Multiplus II 48/5000/70. The guy is insisting on using a 3 phase Fronius for the photovoltaic panels, and he's not able to explain me why he doesn't want to use Victron Solar chargers instead.

In theory, I would prefer that the solar energy goes from DC to batteries DC, right?

What would be the advantage of using an AC coupled Fronius inverter? Easier install for him?



sorinpopa asked
enodev commented ·

5 Answers

Système PV réseau onduleur réseau fronius + Victron

Bonjour à tous,

Je suis entrain de configurer un système PV sur site isolé de 250kWc avec FRONIUS + VICTRON QUATTRO. J'ai proposé 6 VICTRON QUATRO de 15 kVA et 9 Fronius ECO de 25kW, la capacité de la batterie est de 400kWh (j'ai utilisé 84 batterie PYLONTECH de 100Ah/48V.

je souhaite savoir si la configuration est correcte et si vous avez des propositions à me faire ?

pour le système de monitoring (GX touch 70 Victron, Gerbo GX Victron , Modem GX LTE 4G Victron ) , est ce que la liste des composants est exhaustive ? si non faites mois des propositions de ce qui manque svp .

Merci beaucoup

fofo94 asked
Thierry Cortassa (Victron Energy Staff) answered ·

2 Answers

Victron System + Froius Symo Hybid NON MICROGRID!


I would like to install a Victron system on my existing solar installation that is made with Fronius Symo Hybrid.

The project will be like this:
please see configsolar-victron-fronius.pdf attached file

GRID(3PhaseRST) goes to -> IN VICTRON x3 MultiplusII(RST)->(OUTs VICTRON) goest to Fronius Symo Hybrid

All inverters(Victron and Fronius) are set NOT TO INJECT IN GRID. So Fronuis inverter will be set NOT TO INJECT into Victron Outputs in this case because for Fronius inverter will see the Victron's Outputs and is like seeing the grid.For Fronius the GRID is Victron's OUTPUTS. Basically every system will take care of it's own job and will not communicate one with each other, NO MICROGRID here. Every Inverter makes storage of energy and activates it's outputs power when is necessary but WITH NO EXPORT of energy!

So Victorn inverter is coupled with AC GRID (is in sync with the network GRID) and Fronius is in Sync with Victron's Outputs. When the main network Grid fails ... Fronius remains connected to the backup Victron's Outputs. So Fronius will not even see that the main network is down.

In the other mode of functioning ... both inverters will not export enery to Grid and Fronius is limited not to export to Victron either. Like I've said every system will do it's own job not communicating with eachother.

again See pdf file with the possible configuration: configsolar-victron-fronius.pdf

Q1: I wonder if anyone tried any of that configuration and maybe not only with Fronius inverter ... but maybe with other types of inverters that are limited to export? in this case we don't need the Microgrid option activated.

I'm posting this question because I'm only afraid it will not work only of 1 thing :
Fronius is set NOT TO INJECT ENERGY into GRID(this case into the Victron Outputs) but somehow there will still be some leftover injected energy sometimes... like 100W or 200W (for about 1-2seconds) of energy leftovers that escapes the condition part of not injecting.

Q2: Will that phenomenon affect Victron inverter? since also Victron inverter will be set on NOT TO INJECT... ? will some protection be activated on the inverter? even though is such a small escape of energy?
Q3: Could I set Victron to store the leftover Energy into the storage Battery? and not have any issue with the minor escaped energy from Fronius?

Thank you!

highlow asked
highlow answered ·

1 Answer

Fronius Symo Gen24 PV point on AC-OUT possible?

Hello everyone,

I have Multiplus 2 3000 with pylontec battery (on phase 1) and a Fronius Symo Gen24 5 Plus.

  |----- Fronius 
  |----- Multiplus 2 ------- Pylontec US2000           

The fronius is connected to the multuplus on AC-IN.

The fronius has a separate power outlet for grid outages (it's called PV point). If the grid goes out it supplies up to 3kW on this outleg, if there is enough sun.

My idea is to connect the PV point to the AC-OUT of the mutliplus.

The idea is if there is an outage the battery can be charged by the PV point and/or supplied a load on AC-OUT.

There are some posts already that go in that direction, but none seem to be conclusive on how to set this up.

Is this setup even possible?

Any help is appreciated.

cheers, matti

matthias-fuchs asked
sharpener edited ·

2 Answers

ESS export to grid mainly at defined hour intervals

Hello community!

I have the following task: find a way to use the Multiplus II to export energy to the grid at programmable hour intervals (day, night, independent of PV production times).

Why: At the moment I receive 0.05 € per exported kWh so I am studying the possibility to change my energy subscription to a hourly tariff based on the market price of energy. Each day the prices vary wildly from less than 0.01 € at noon to 0.90 € in the evening and 0.80 € at night with some peaks even more than that. My goal is to store PV production during the day and export it during the best paying hourly time slots to shorten my amortization period.

My system: Multiplus II 8000 as ESS with 60kWh LiFePO4 battery and a Fronius 8kW on the output, grid metering is done by the Multiplus II, all consumption occurs on output

Current usage: I am already exporting mainly at off peak times (mornings and afternoons) because the grid is swamped with PV energy at noon, raising the system voltage close to PV inverter shutdown values (> 256 Vac). Also my grid connection is not the best as I get about 0.8V raise for each kW exported.
I solved this by automatically lowering the battery max charge power value in Cerbo GX when the grid voltage is low (preventing battery charge) and raising the battery max charge power when the grid voltage is closer to 250 V to direct more energy to the battery.
2 x 3kW water heaters are on standby and ready to activate if grid voltage raises over 252 V when the battery is full.
This whole setup works perfectly and the Multiplus II stays connected to the grid while the Fronius PV inverter never trips anymore.
Before implementing this adjustment, at around 11AM the batteries were full, the PV inverter would shut down due to over voltage protection and the Multiplus II would disconnect from the grid.
This whole automation is done using MQTT and Node Red thanks to the Victron system being so open and friendly.

Back to my new task and problem:
I have found no way to directly program the Cerbo GX to export at any desired hour. Is there a way to force Multiplus II to export during the night from battery storage? That would be the best option since I only have to program the system to export energy during the best time slots.

Second solution that I can see would be to implement a smart meter connected at the grid point. Read data from this smart meter and send it to Cerbo. When export is desired I can change consumption data in order to make the Multiplus II invert more than is consumed on the output.
Can the Multiplus II cover consumption on the input if fitted with a smart meter at the grid point?

Third solution (that I try to avoid) would be to use an extra battery inverter only for export purposes. This would again increase system costs and change the amortization period for worse. If this remains the only choice, does Victron have a product that fits this use case?

Not afraid of programming it all, just wanted to run these options by the community, maybe there is some info that I am missing - been using this Victron system for only 3 months now.

vicuser77 asked
nickdb answered ·

2 Answers

Victron Qauttro (x3) with Fronius 3phase (x1); Zero feed-in per phase not working.

We have installed a 3-phase system consisting of 3 x Victron 8 Kva's and Fronius Symo 20.0-3-M. The phase’s are not balanced by default as loads don't draw at same time. The problem is now that with one phase drawing higher loads than other two, the Fronius is throttling to the highest phase from loads, the two other phases (equivalent to the one or more loads being fed by Fronius via the Victron’s) then is being feed into the grid past the Victron energy meter.

How can we limit this feed into grid?


Tcp is enabled, PV inverter has been assigned, but at the TCP finds no IP address. Even if we enter the address in manually it does not change the feed into grid. All settings on Fronius match. Out of ideas to try and make this work.

jaqibar asked
Matthew Walsh commented ·

3 Answers

Fronius on input does not charge batteries

We have a site with a Fronius Eco on input and 2 x Fronius Eco on output. Zero Feed In enabled and we often find ourselves in a situation where battery needs charging but the Fronius on the input seems to be being throttled. Given that Venus knows about the Fronius on the input, can it not choose to charge from grid up to the threshold of what the Fronius can produce?


Warwick Bruce Chapman asked
Matthew Walsh answered ·

3 Answers

Fronius not producing ESS AC Coupled

We have a problem with our system for a client. The AC coupled Fronius inverters only supplies loads and doesn't charge the batteries. I've updated the firmware's on all Victron devices, batteries, and Fronius but still does the same.

I followed this guide as main setup: Victron Three phase setup
Then this guide after main guide: Victron Fronius setup
Then lastly the ESS setup with zero feed-in (4.3.11): Fronius Zero Feed-in

The system is up and running, all devices are detected and running as should, except the Fronius's are being throttled.

We first had the system off-grid (Client only later on decided he want's the grid as backup), the grid codes were set to Microgrid 50 and was only using Frequency shifting when throttling, when we tested it like this (About 3-4 days) the system operated 100% correctly, we switched off and left as site was still being established.
A month later the client pulled in the AC supply (from grid) cable and we went back to connect it, I noticed the system didn't throttle the PV when batteries are full because (obviously) the system stuck to 50Hz as it came in from the grid. I changed all grid codes to South Africa (NRS 097) and then I used the Fronius Zero Feed-in guide above to limit the Fronius inverters via TCP. This works and only feeds back minimally, but the PV throttles when loads drop, it shouldn't- it should charge batteries and then only throttle.

The system consists of:
Three phase setup
6x 15kVA Quattro's (2x per phase)
10x SolarMD SS4143 (143kWh)
4x Fronius Eco 27.0-3-S Inverters (1:1 rule was adhered to on DC side)

Any assistance would be greatly appreciated!

francois asked
Matthew Walsh answered ·

1 Answer

Micro-grid with MultiPlus II and Fronius Primo - causing flickering lights


We built a new single-phase installation recently with the following components:

  • MultiPlus II 48/5000
  • Cerbo GX
  • 4x Pylontech US2000C
  • PV inverter Fronius Primo 4.0

Grid is connected to MultiPlus AC in, all loads and the PV inverter are connected to AC out 1, like so:


Grid metering is done by the internal meter of the MultiPlus, Fronius is connected via ethernet (zero feed-in with ModBus via TCP).

Generally speaking, this setup works really great, now we're getting to the last 10% of optimization, and the current issue is the transition from grid-parallel to micro-grid, which causes the following:

  • Error 105 on Fronius (AC frequency too high) when switching off the connection to the grid (Fronius restarts/recovers quite quickly though)
  • Flickering lights at certain load constellations while operating on micro-grid (e.g. Fronius delivering 2.5 kW and loads around the same value (oven + small toaster)

The flickering can be described as brightness oscillation around 1-2 Hz, as if MultiPlus competed with Fronius for the voltage regulation. If useful, I can upload a video later.

Parameters are set as recommended by the documentation (MG50 on Fronius, Frequencies set in the ESS assistand according to Native Fronius zero feed-in works fine also. The documentation mentions "Q5 How can I get the Fronius firmware that improves flickering?", but the Fronius is brand-new and all firmwares have been updated, so this shouldn't be the point.

Any ideas and help is much appreciated :-)


ips-ad asked
Rob Duthie commented ·

3 Answers

Fronius Primo 5.0.1 voltage pulsating problem after new firmware (MicroGrid Multiplus 5000)




The problem was the new Fronius Primo firmware version! All you have MG50 setup coupled with Victron inverters please avoid doing firmware update to Fronius inverters to fro32482.upd version, or ask Fronius to downgrade to a version from late 2020 via SolarWeb interface.


I have a big problem with a Micro Grid system (OffGrid, Multi 48/5000 with Fronius Primo 5.0.1) MG50.
A few days ago I did a firmware update on Fronius and since then the AC voltage fluctuates a lot (see the image on the attached graph).

At 12:11 I did a firmware update on Fronius and since then the AC voltage is very unstable.

The inverters also make a pulsating sound.
The Multiplus has latest firmware version 2624494, Fronius Primo has the firmware version fro32482.upd (inverter), 3.20.6-1 (data source).

Please help me, it fluctuates so much that the light bulbs in the house flicker when I start the Fronius.
When only MultiPlus works then everything is ok.

Does anyone have an old Fronius Primo 5.0.1 firmware version? The new one completely ruined my system.

Thank You!

frasinburg asked
mgstrad commented ·

11 Answers

Implementing ESS by changing Smart Meter to EM530 Grid Meter

We have a setup that includes 3 x Multiplus running in parallell on 3-phase and an AC coupled Fronius Symo. Grid-Feed-In is not permitted so for the past 12months+ it has been running with a Fronius Smart Meter.


One unintended consequence of this design is that it cannot run as an ESS, so the battery sits idle at 100% except when there is no-grid. When the grid drops the Fronius sits on the non-essential side and has been working happily.

We would like to convert the system to ESS so I have purchased a Carlo Gavazzi EM530 and plan to connect this to the Cerbo GX using an RS485 to USB cable.

The questions I have are:

  1. In the new ESS setup if I enable the zero feed-in will the GX do the same job of throttling the power output of the Fronius?
  2. Can it do this through the existing Ethernet connection between the Cerbo and the Fronius Datamanager?
  3. I assume the Fronius Smart Meter will be redundant?
  4. Without the Smart Meter can the system still talk to the Fronus SolarWeb portal?

Happy to answer questions, provide info. Q 1 & 2 are the essential ones.

Thanks so much in advance. I sometimes find it tricky answering these kind of questions from manuals and building confidence, so this kind of help is so useful.

tim-hickman asked

0 Answers


351 Posts
237 Users

Topic Experts

275 Points
52 Points