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Can the Fronius zero-in feature be used when no grid is available


I have successfully been able to use the Fronius zero-in feature when the grid is avaiable to use. I can correctly see that the value of the Fronius zero-in feature active item is indeed 'yes' and everything is working accordingly.

When I have a main loss, the cerbo disables the Fronius zero-in feature and proceeds to frequency shifting in order to limit the inverter. Why isn't the Fronius zero-in feature activated when we are in this particular case when I can still send information to the Fronius via modbus? Can it be activated?

Is the Fronius zero-in feature only avaiable with ESS? Is there another assistant that can potentially use this feature with generators?

Thank you

bricecre asked
puitl answered ·

2 Answers

Victron/ Fronius 1-1 rule.

The 1-1 rule a maximum as i understand it. So there should be no problem having 3 x 5KVA MP2 in 3 phase config with 10.3 fronius Symo as the AC PV.

woodsy64 asked
Jons Collasius answered ·

1 Answer

Victron Fronius AC wiring diagram

Hi all. I've done some DC coupled systems, but I am new to the AC coupled world. The idea is to put a Fronius ECO on the output of 3 x 15KVa quattro's. The documentation doesn't help to much regarding this matter for newbies. Can someone please help me better understand the AC wiring side of this? Will the literally be connected together on the same AC lines (on a breaker of so)?

xdk asked
matt1309 edited ·

1 Answer

Multiplus-II + couplage AC Fronius Primo


nous avons installe un systeme avec Multiplus-II , cerbo-s et Fronius primo en AC OUT 1.

Tout le monde apparait sur le l'ecran deporte. Les parametres ESS sont bien ceux repris dans la documentation.

Pourtant nous avons du loupe un detail car le Fronius delivre 40 W, preque rien n'est pris sur la grid, toute la puissane fournie a la charge est extraite du banc de batteries.

Si nous retirons les bouchons des ports bus du fronius, il produit alors ce qu'on attend du champ solaire et la batterie se charge, mais le Fronius a disparu de l'ecran du cerbo (et sans doute du VE.bus).

J'en deduit que c'est le multiplus qui restreint le fronius. Mais je ne vois pas sur base de quel parametre(s)? J'attendrais qu'il produise plus et charge les batteries...

Ni pourquoi rien n'est pris de la Grid? Peut-etre est-ce le comportement normal jusqu'a atteindre le niveau minimal de charge de la batterie programmee?

Apres environ 5 demi journees sans succes, je m'arrache les cheveux et desespere un peu :(

toute piste d'idee serait un bonheur ;)



jeanscotch asked
Thierry Cortassa (Victron Energy Staff) answered ·

1 Answer

Fronius on AC-in limitted with battery under 70% SoC

I have two MPii's 3kVA in a parallel setup with two Fronius inverters. I have a 2.5kW Galvo on the ACout of the Multi's and a 4.6kW Primo on the AC-in side. I also have DC coupled PV.

With the battery still under 70% SoC, the Primo's output is being cut back while the Galvo's is not. If I switch on "feed in excess AC coupled PV", the Primo ramps up to full output and the Multis ramp up charging to match so there is still no actual feed in happening.

Is this a bug or have I done something wrong with my setup? The behaviour I expect is that the Primo should only cut back if the battery is full or if the charge current limit is reached, neither of which is the case here.

paulcupine asked
ponzoa commented ·

1 Answer

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 ·

3 Answers

EM24, Fronius Gen24 Plus 5k on AC in

Hi everyone,

I have a Fronius Symo Gen24 Plus 5k which is on AC in and exports to grid, I have a fronius smart meter but it is used only for getting the statistics in Solarweb, no export limitation. The system is three phase.

I have a single EasySolar II which I use mainly for critical loads. I purchased an EM24 and I want to put it next to the Fronius Smart meter. I want to see the Fronius on AC in, AC loads, critical loads etc. I do not think this should be a problem. Question is can EasySolar II also give surplus solar to the AC loads on AC in without exporting to the grid? If Fronius exports to the grid the EM24 should see that but I am not sure how this can influence how much power EasySolar sends to the loads on AC-in.

Thank you!

Robert Boerescu asked
matt1309 answered ·

3 Answers

Victron Comms with a Fronius Tauro?

Can Victron communicate and control with the Fronius Tauro as it can with Primos, Symos and Ecos?

Kym asked
dolis commented ·

1 Answer

No ESS assistant found - fronius PV inverter

Good evening, seeking for some help.

We installed a Fronius ECO 27.0-3 inverter with a Victron energy meter EM24, and a GX. We do not have a battery inverter installed nor do we have a battery system but want to control the Fronius grid feed via the GX. Customer will expand later on with the battery inverter that is why we wanted to install the Victron energy meter.

I am trying to setup the GX but because there is no battery inverter I cant seem to get the ESS assistant running to control grid feed.

How can I achieve this,


jacodutoit asked
Alexandra commented ·

1 Answer

Adding 3 phase Fronius to single phase Multiplus system

I have 3 phase grid. Curently I am running Multiplus 48/3000 with 4 kW solar and 15kWh battery. ESS assistance. Mainly critical load is powered.

I need more solar generation to power 3 phase heat pump. No plan to add more batteries , it is enough to be partly offgrid for 2 days and grid feed-in and storing is much cheaper than extra batteries.

How shall I expand?

Option 1. Adding 2 more Multiplus with more solar controlers and extra solar panels (total inverter power - 3×2.4 kW)

Option 2. Install 3 phase 10kW Fronius Symo PV inverter with extra solar and use AC coupling on Victron grid-in. (Tital inverter power - 10kW+2,4kW)

I am tent to go for option 2, but not sure if this is even feasible?

Can not find on Victron page.



mindaugas asked
Michelle Konzack commented ·

2 Answers

Fronius PV point as AC IN

Hey everyone,

I have a fronius symo gen 24 AC coupled inverter and a Victron easy solar 2 which I use only on one phase as backup power for some critical loads. There is no integration between these two. Easy solar mppt has four panels. Fronius 14 panels. I was wondering if I can put the fronius pv point output which comes up only as a backup solution giving up to 3kw power when AC grid goes out and there is sun as a AC in for Victron using an automatic transfer switch. The solution will be like this: when grid goes out, Fronius output to the grid goes out, victron ac in from grid goes out, Fronius pv point comes up in max 90 sec if there is sun and gives up to 3kw, automatic transfer switch goes to input 2 which is fronius pv point.

Does it make sense?

Robert Boerescu asked
matthias-fuchs commented ·

1 Answer

Multiplus ii increases the frequency, and fronius error 105

Hi, I'm Daniel. I have a question about my ESS system.

It is an ac coupling system with fronius primo 5, and multiplus ii 48/5000, and 360Ah of 60v batteries.

The fronius is in ac out configured in mg50.

The question is that when I lose the voltage (ac in), the system continues to work in isolation (all correct). When the voltage (ac in) is restored, the multiplus increases its frequency until the fronius disconnects (error 105), until a few minutes pass and it synchronizes again..., all this regardless of the battery soc.

Does anyone know what this behavior is due to?

Thank you.




dani asked
Rob Duthie commented ·

3 Answers

Fronius Gen 24 -> AC OUT Multiplus

Hello, I have a question

I will bye 3 * Multiplus II 5000, a MPPT 450/200 (with about 14kWp) and a BYD LVL 15.4

A Fronius Gen 24-10 and a Byd HVM 13.8 kwH are currently in stock and working (with about 13kWp)

The question now is can I switch this combination (Fonius + BYD) behind the Victron?

eg. Connect the Fronius to AC-OUT 2 and if necessary (in isolated operation) limiting the Fronius to 5kW AC output (if necessary) and switch it to AC-OUT.

German Version:

Hallo ich hätte eine Frage

Ich werde 3 * Multiplus II 5000 verwenden dazu einen MPPT 450/200 (PV Leistung ca 14kWP) und einen BYD LVL 15.4

Im Bestand sind aktuellen eine Fronius Gen 24-10 (PV LEistung ca 13kWp) und eine Byd HVM 13,8 kwH

Die Frage ist nun kann ich diese Kombi (Fonius + BYD) hinter den Victron schalten?

zB. den Fronius auf AC-OUT 2 und bei Bedarf (Im Inselbetrieb) den Fronius auf 5kW AC LEistung begrenzen und dann auf AC-OUT schalten

snu-pi asked
transfersolar answered ·

9 Answers

New fronius Gen24 product support

Does anyone know if victron are supporting the new Symo/Primo Gen24 models?

Anybody know if they are detected and read by the VenusOS?

alan asked
transfersolar answered ·

3 Answers

Fronius Primo GEN24 Plus integration?

For the Victron guys:

I see that the Fronius Primo GEN24 Plus will be available in 2021. Has there been any integration testing done on this unit and is it something to consider over the current Primo models? My plan is to add a PV Inverter sometime this year so I might as well go for the new GEN24 unit if it has been certified by Victron. I won't use the Battery connection feature but I like the Active Cooling as my kit is in a warm environment already.

Quattro/VenusGX/Smart Solar Charger/LiFePO4 CAN Battery.



Ingo asked
transfersolar answered ·

2 Answers


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