fronius off-grid Image

fronius off-grid

This topic has been merged into Fronius . Please use Fronius when editing or creating new content.

Fronius, Multi & generator


I have off grid, AC coupled system with Multiplus 3000 and Fronius Primo 3.0, 24 V battery and generator.

Generator is switched on manually. Problem is when I turn on generator, after half minute on Fronius is error code "105 AC freq too high" and fronius going to reset.

After reset again coming new reset..

Does anyone have an idea what the reason is?

Also, I am afraid about returning power from PV to generator in case of sun coming.

My idea for solve problem is install AC/DC 230/24 V charger directly from generator to charge battery in case of empty battery (few times per year)

What is your opinion?

vedran asked

0 Answers

Fronius Symo 6 integration with Victron

This question might seem a bit odd, but please cope with me for a moment.
I will have my Fronius Symo 6 inverter coupled at AC-out of a 3-phase Victron Quattro system. There will be a smart meter (EM24 ethernet) right at the Fronius to allow reading of its output.

My question:
How does Victron interface with Fronius here? Is there some need to talk to the Fronius inverter at all? If so? Why?

Why I am asking this?
In case I put a load between the Smart Meter and the Fronius, this might lead to an issue, if for example the Fronius, via modbus TCP, tells it delivers 4000W, but the smart meter reads only 2000W (because the other 2000W go to the load in between). Right? Wront? Weird?

sesshoumaru asked
Matthias Lange - DE answered ·

1 Answer

ESS flapping between absorption and discharging

In the ESS System, when there is a stable situation with enogh exceeding energy - Bulk Charging is working well – but as soon as the batteries are sufficiently charged to switch to absorption, the Multiplus is flapping between absorption and inverter (discharge) mode in changing intervals of 10sec to 1 minute and with changing amplitudes up to +/- 10 Amps. I would expect a stable absorption mode with constant voltage and decreasing current for the configured absorption time of 2 hours – but no negative current at all.
I already have posted the problem in german language "ESS springt zwischen Absorption und Discharge alle paar Sekunden" but unfortunately no solution yet and therefore i repost in english language and with extended documentation.
I have done a lot of measurements and tests - see attached documentation also including configuration parameters. 2022 01 14 Absorbtion Problem Doku.pdf

Looking forward to your recommendations - Manfred

manfred-1 asked
manfred-1 commented ·

1 Answer

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
Warwick Bruce Chapman commented ·

2 Answers

2 Answers

Ohmpilot in ESS with Multi/Quattro and Fronius Primo on AC output


Main reason why I'm asking this is because ESS manual says the Fronius SmartMeter can't be used in Victron/Fronius ESS setup.

My goal is to use PV power mainly and primarily to produce heat (second to use the surplus, third to store the surplus).

My idea was to set up the system like in the diagram attached and configure Victron ESS with "control without grid meter" = OFF


The Fronius SmartMeter would only be used for the Ohmpilot to know how much energy can be used for the boiler (Surplus = "PV engergy" - "Critical loads energy")

My questions are:

- Will this have an impact on Victron/Fronius ESS setup?

- Will Fronius Zero feed-in still work?

Many thanks for your thoughts and Merry Christmas!! Mike

freytshy asked
Agropensiunea Cerna commented ·

4 Answers

Anti-Islanding-Protection Austria (3-phase ESS-System with Fronius AC-coupled PV)


I am an electrician and planning a ESS-system for my new house in Austria.

3x Multiplus-II 5000 (3-phase) with 48V Lithium-Battery (maybe some Pylontech US3000), with about 6kWp Fronius Symo PV-Inverter connected on AC-Out for higher self-consumption and UPS in case of grid failure.

Is there an extra anti-islanding-relay necesarry, or is the anti-islanding-protection from the Multiplus II enough? I only find the TOR D4 Certificate for Multiplus-II 3000!

Thanks for the Answers!


Erwin Heigl asked
chesch commented ·

4 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
jaqibar answered ·

3 Answers

Fronius symo light with cerbo gx


I have two 10kW fronius symo inverters. I would like to monitor these devices via the cerbo gx.

In order to do this, i need to purchase a fronius datamanager (2.0) to take input the inverter(s) in the same network as the cerbo. (conform this method:

My questions:

- is it necessary to buy two datamanagers for the fronius inverters because they are coupled via modbus i think?

- When I want to monitor the power consumption and powerdelivery, is it even necessary to connect the inverters to the cerbo? Can't i just connect 3 currentmeters to the cerbo and do it like that?

Thank you very much

Kind regards

aernoo asked

0 Answers

Fronius Inverter does not appear on VRM portal, why ?


The Fronius inverter is shown on the Venus but not on the VRM portal or it does in advanded but now in the overview


Above shows the Fronius and VRM portal below doesnt show it :


but in theVRM portal i see following in Advanced :


and here it's not shown :


What could be the reason ?

peternielsen asked
peternielsen commented ·

7 Answers

Can the PV inverter support assistant be configured to start ramping down at 57.6v instead of 54v?

At the moment the absdorption saying is 57.6v for absorption but the PV inverter support assistant ramps down Fronius when the batteries are at 54v so it takes far too long to charge the batteries under solar. When the generator is on, it will charge at 180amps until 57.6v then go into absorption then float as it's supposed to but when it's under solar it will charge at 180amps to 54v then ramp down considerably so even though the charger wants the power the PV inverter assistant won't allow it. Can the setings be changed in the PV inverter support assistant to chasnge it from 54v to 57.6 as per the charger setting?

daren-connor asked
Andrew Ayles commented ·

1 Answer

Voltage and Frequency pulsating - Multiplus 3000 + Fronius Primo 3.0-1

I have a very annoying problem with my off-grid setup of a Multiplus II 48-3000 and a Fronius Primo 3.0-1 PV Inverter. As soon as the Fronius connects its Power Unit through, the voltage starts oscillating from 200 to 250V and the frequency (according to my Cerbo) from 49.9 to 50.1, as you can see here: MAP001.jpg

It stays this way as long as the MP is charging the Battery (200Ah LiFePo4, no limit from the Battery Current etc.) or as long as there are no loads > 500W delivered from the battery (e.g. I turn on my heater).

As soon as the frequency rises above 50.2 Hz (when Throttling) the problem disappears, so I assume there are some regulators oscillating which parameters I can't change.

I've already tried updating the Firmware both of the Muptiplus as well as the Primo. The Primo is on the MG50 setup, the MP has the PV Assistant loaded.

I've tried to adjust the voltage between 210 and 240V, which has no effect. If there was a way to fine adjust the freqency I would do just that, as it would solve the problem to set it to 50.3 or so, as I have no clocks on the system, but there seems to be no way to set anything except 50.0 or 60.0 unfortunately - whereas with 60 Hz the issue is also there.

I'm kind of disappointed as everything works fine except this problem, which seems to also affect my batteries, because the battery current also oscillates quite much as a result, which causes problems when balancing.

Thanks so much for your help!

kaffeetasse asked
kaffeetasse answered ·

1 Answer

Fronius Primo with Multiplus II 48v 5000

Please need some guidance and assistance please.

Have installed the following at my residence (home):

14x 595W Canadian Solar panels

Am wanting to connect to the following items as listed below into a Grid Tie system to cater for Solar power to power the Home during the day as well as charge the 2 x Pylontech 4.8Kw/h batteries.

The ideal is that in the evenings we will use battery power and then the following day the batteries will charge again. Am also in addition wanting to ensure that when we have a grid power failure, I still have electricity to power my home.

1x Fronius Primo 8.2kw Single Phase Inverter

1x Victron Multiplus II 48v 5000/70/50

1x Victron Cerbo GX

1x Victron GC Touch 50

Please can you guide me as to the best possible means to connect the device to cater for my needs.


harryp asked
baxter answered ·

1 Answer

Battery voltage limit

We have a couple of Multiplus v2 5k, a 5k AC coupled Fronius, 4 BYD b-box LV 48v batteries and a Cerbo to tie it all together.

Now I want to limit the charging voltage on the BYD batteries from 58.4 volt to 56.4 volt. According to Will Prowse this will greatly increase battery lifetime. Please correct me if I'm wrong.

I have no idea how to do this. In Venus OS, the CVL option under the BYD parameters is not changeable. Do I need to do this in the BYD software somehow?

Thanks in advance,


yagu asked
yagu answered ·

2 Answers

Fronius on ESS without MG50?

Hi there,

since Fronius Support is taking some time to answer the question, I might as well post it here.

The local utilities require a specific cosPhi setting in the inverter, which - for my knowledge - requires a countrysetup other than MG50.

How does changing from MG50 to i.e. DE2U affect the behaviour of the inverter in an ESS?

Feed-in only needs to be limited to 70%, so no zero feed-in required.

As always, thanks for the help!


chriss83 asked
baxter commented ·

3 Answers

3 Phase Multiplus 2 - Configuration


I would like to implement the following system at my home and would be extremely grateful if someone could confirm whether a Multiplus 2 system as depicted will provide me with the listed functionality.

Regards, and thank you in advance.

Config_Essential Load with ESS_Sensors.pdf

josepgom asked
Rob Duthie commented ·

5 Answers

High grid voltage and throttling with Multiplus II in Australia

During peak solar times around the middle of the day, my MultiPlus II sometimes will disconnect from the grid in times of high voltage (as required), because it does not throttle back the power being exported (soon enough).

Powercor say my grid voltage is within specification, yet I find it usually is not possible to export 5kW to the grid without exceeding high voltage limits. (Maybe they keep the grid voltages high on purpose!)

To me, the problem lies with throttling back PV sources.....and I question whether it is the Grid code, V1-V4 values for Volt-Watt response curve that trigger the throttling?


My settings (pictured) do not match those that my distributor (Powercor) recommend, where they say V3=253 and V4=259.

In my case, I have a DC-coupled MPPT charger which does throttle back, albeit a little late....

Also I have an AC-coupled Fronius inverter which I was told before commissioning that it would be controlled via frequency shifting. This I believe cannot happen whilst connected to the grid and instead can only happen through a Modbus TCP connection. Throttling will work using Modbus, but again too late!

--> What settings will allow throttling to occur sooner?

Furthermore, when using Modbus the GX device shows the Fronius connection as (sunspec) and the Fronius status as "Running(Throttled),
versus not using Modbus it shows the Fronius connection as (solarapi) and the status as "Running".

When using Node-RED to retrieve data, sunspec & solarapi behave differently - with solarapi giving better information for Status and Error codes.

--> Can we use Modbus for throttling, and also use the solarapi connection?

Any help appreciated!

smart-home asked
David answered ·

1 Answer

Adding Victron to existing grid-tied Gen24 + BYD HVS system

I have an existing grid-tied system with a 7kW of panels to a Primo 6kWh Gen24 with 7.7kW of BYD HVS hooked up.

I would like to add a 48V Victron to the system and add batteries, probably Pylontech, and I will be adding a wind turbine to this system, but not initially. What would be the best setup to not mess with my current setup too much, but such that I can fill the Pylontech batteries from both the grid and the panels?

travellinground asked
marekp answered ·

1 Answer

conect fronus and victron
I want to connect the fronius primo 8.2KW with victron Quattro 10Kw to the network but I don't want to consume anything from the network only from batteries. Can something like this be done? What scheme should I adopt? Can someone help me? 
Thank you. Mariani

marian-rada asked
Alexandra edited ·

1 Answer

Existing Fronius System extended with Victron Multiplus II

I've got a Fronius Symo 6.0-3-M with a Fronius Smartmeter up and running for more than a year now and I want to extend it with a Lead-Acid battery and the Victron Multiplus II 48/3000 GX.

The Fronius is connected to AC-in of the Multiplus II and there is no need to limit the feed-in power to the grid.
Is it possible, that the Fronius tells the Victron how much power is going to/from the grid to charge/discharge the battery accordingly so that (if SOC is in range) the powerflow to/from the house is ~zero ?

I've already asked Fronius and they answered it is possible, because they communicate via SolarAPI:


( Link to commets)

Nevertheless it was not possible for me to get the Multiplus II to work properly.
It always shows the Alarm: AC-Input: Not available

I connected both to the same Wifi and the Victron already found the Fronius Symo, but it only receives the produced power by the PV-Inverter and the AC-input is not seen for the Multiplus II.

Victron VRM-Portal:


Fronius Solarweb:


Is this even possible or do I need to install an extra energy-meter compatible with the Victron Multiplus II?
If it is possible, what configurations do I need to set?

Thank you in advance,

mazoner asked
mazoner edited ·

1 Answer

ESS Anlage mit Meßwandelzähler und Fronius Symo

Hallo Liebe Victron Gemeinschaft,

Ich plane eine Photovoltaik Anlage anzuschaffen und benötige für manche Punkte die Erfahrung vorhandener Nutzer.

Der Entwurf der Anlage ist sehr stark an die Beispiele von Victron angelehnt.

Der größte Unterschied ist das Netzseitig ein Messwandelzähler 200A/5A verbaut ist und somit der einfache Victron EM24 nicht infrage kommt.

Daher sieht der Entwurf einen EM24 mit Messwandelzähler und ModbusTCP (EM24DINAV53XE1X) vor.

Die erste Frage ist, ob dieser EM24 (EM24DINAV53XE1X) kompatibel mit dem Victron System ist.

Die zweite Frage wäre, ob das System folgende Funktionen erfüllen kann:

- Eigenbedarfs optimiert

- im Normalbetrieb versorgen die Symos das interne 3 Phasen Netz über die vorhandenen Unterverteiler

- sollte keine Energie im internen Netz abgenommen werden wird der Überschuss von der PV Anlage in die LiFePO4 Batterien geladen

- steht keine Energie von der PV Anlage zur Verfügung, versorgen die Multiplus-II das interne Netz (sowohl ACin als auch ACout an den Multiplus-II) bis ein gewisser SoC erreicht ist, weitere Leistungen, die die Fähigkeit der Multiplus-II und/oder Batteriekapazität übersteigen werden aus dem öffentlichen Netz genommen.

- Im Falle eines Ausfalls des öffentlichen Netzes, versorgen die Multiplus-II die IT-Technik unterbrechungsfrei innerhalb der Grenzen der Batterie


joergsc asked
joergsc commented ·

1 Answer

2 x Multiplus II, Grid tied, with 32kWh battery, Solar Primo 8.2

Hi there,

Is there any SLD or connection diagrams available for following setup?

Can someone please guide us for our first install with Victron? Any suggestions or tips?

I have attached BOM as well




adaptenergy asked
Rob Duthie answered ·

2 Answers

fronius and em-112

Tengo un multiplusII con cerbo y un fronius primo, he instalado un ET-112 pensando que el fronius lo detectaría pero no me funciona, también use el EM-111 que es el que tengo ahora puesto con el cerbo pero el fronius no lo detecta. Me podéis decir si es compatible y como se debe conectar en caso de serlo?

mianfrar asked

0 Answers

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 ·

3 Answers

Equivalent AC (PV) Inverter support on SMA as on Fronius systems


given the sunspec (modbus) support the current 3p SMAs have, could i expect an equivalent set of features and integration options as Fronius systems have already in the past ?

martghh asked
robert-campbell answered ·

2 Answers

8kW setup with Multiplus II and Fronius Primo

Hi everyone,

I'd like to get some feedback on the following.

I currently have the following setup:

- 3kW Multiplus II
- 3kW Fronius Primo connected to the ACout of the MPII
- 9kWh AGM battery bank
- Grid tied system with the ability to export electricity

This system works great in a grid down scenario where the PV array continues to provide power to the Multiplus II.

I like the simplicity of the setup and am looking at upgrading the system to an 8kW system (both for the Multiplus and Fronius Primo due to the 1:1 rule). I would also be upgrading the battery bank to 18kWh AGM's. The Fronius Primo would be the following model:

Question: should I be concerned that this type of setup is too big and should this only be suitable for the smaller setup that I have? I.e. would the Primo be able to throttle back sufficiently if there is only a very small AC load and the batteries are already at 100%? Your thoughts on the battery bank capacity would also be appreciated.

Any other thoughts and comments are also welcome.


casper asked
Rob Duthie commented ·

1 Answer

fronius stop working with 105 error

i have 3 numbers 3 kva inverter and 10kw fronius symo inverter with Venus, when ever one of the mains input (L1 or L2 ORL3) disconnect only two phase available victron moves to inverter mode , as soon as victron moves to inverter mode fronius stop producing power and gives 105 error which is high fz. There is 2kw load and my battery around 78% still fronius in same state.mod bus settings are same as per recommend , victron set with ESS ,Then tried with pv support assistant still same result .Please confirm that its controlled by victron settings algorithm or any settings need to be adjust. Thanks.

kaarthik asked
marekp answered ·

1 Answer

Cumul des puissances Fronius + Multiplus en couplage AC


Je dimensionne une installation Hors-Réseau avec un Multiplus + couplage AC Fronius Primo + couplage DC.

J'ai bien compris la règle 1:1 en couplage AC.

Mais je cherche à savoir si sur une belle journée et avec les batteries chargées on peut cumuler ou dépasser la puissance du convertisseur + celle de l'onduleur. P_tot=P_Multiplus + P_Fronius

Le client souhaite alimenter une machine de 2000W uniquement lors des belles journée mais avec ces autres équipements il peut y avoir des consommation jusqu'à 4200W au total sur 2h cumulées.

Je pense coupler en AC un Multiplus 3kVA avec un Fronius Primo 3kVA et commencer avec 1.5kWc en couplage DC que je peux facilement faire évoluer.

Le but est de na pas passer sur 5kVA car le client ne consomme pas plus de 2000W 70% du temps

Merci de votre lectures et vos réponses

tdy74 asked
Thierry Cortassa (Victron Energy Staff) answered ·

2 Answers

Fronius Primo Inverters / Smart Meter integration with Cerbo


I have a 2 phase installation (80A per Phase) with the following

Main Switchboard with installed fronius smart meter

Sub Board (located 130m from mian Board) with 26.25kw of solar (4 x Fronius Primo Inverters)

Solar is limited to 5kw per phase export with the fronius smart meter.

I would like to connect a cebo to monitor grid import / export, solar production and consumption. The reason I would like to do this is that I already have 5 other smaller off grid victron systems, I would like to keep all of the info in the one system.

1) Connection of the Fronius Primo inverters to the cerbo seem straight foward, can the cerbo pull the fronius smart meter data?

2) If the cerbo cant get that data from the fronius smart meter, what would be the best setup to get all of the site data?

Wes Humpage asked
mvader (Victron Energy) answered ·

2 Answers


217 Posts
13 Users
1 Follower

Topic Experts

0 Points