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Benefits of PV fronius (or similar) over Victron MPPT?

Dear All

I am currently determining how many panels I need (installing bit by bit, as not to overspend). One parameter is sun orientation in winter.

I have read a few articles that states how efficient the PV inverters are (like Fronius). However, if you compere the cost for the Fronius to the Victron MPPT's, it seems that they are a fair bit more.

My Question:

Is it better in the long run to buy a Fronius compared to the Victron MPPT (let say 250/100) with ESS, when considering Return on Investment (ROI)?

My impression that I am getting is that Victron MPPT's are fine and more "modular" (+ROI) with a slight lesser efficiency (DC-AC) , but designing your system "around" a PV inverter will most probably be disappointing.

Just short and sweet answer if you have.

PS, I know that the PV inverter can "pick-up" the load while the Multi is idling (grid active - Pass-through). I also note that some have pointed out that the waveform can suffer on PV when pushing the higher limits.

groningen asked
Alexandra commented ·

2 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
Andy commented ·

3 Answers

Quattro shuts down without any warning/alarms

Hello everyone.

Here's my setup: Quattro 8kva with a Fronius 8.2kw on AC OUT and 2 MPPT150/45, and a BYD LVS 32kWh (8 modules).

I have forever had an issue with high voltage alarms (reference topic and this never changed after 1 year. I have tried keeping the grid/generator for 2 days, set the charging voltage to 55 in DVCC (works until it is removed), and none solved the issue.

That's not my problem however, it's fine, a warning I can live with. Last week, I finally got approved for net metering and our grid company installed the meter so I can start feed-in. All was well and good until the system starting shutting down. Nothing in the alarm log or events, except for the usual high voltage alarm.

Here's what happened:


1. batteries full, grid offline

2. at some point grid came online, feed in started, max cell kept going up

3. first shutdown

4. second shutdown, after that I disconnected the grid

I am making the assumption that this shutdown is from the BYD BMU because of the high cell voltage situation, plus the Quattro doesn't register any other alarms/warnings/events.

My first question is, why at point 2, the high cell voltage kept rising? Batteries are full at this stage and I am feeding the excess back to the grid (only AC excess, not DC).

I have for now set DVCC charge voltage limit to 55V and waiting for the grid to come back online and test this.

Does any fellow Victron user have other thoughts or experience with this?

micmak asked
micmak commented ·

0 Answers

Fronius - Victron - All Critical Loads configuration


I have an installation in my house with a Fronius Primo 8.2 and 8000W of solar panels.
I want to put a Victron Multiplus II with battery and I have doubts about how to make the connection.

This is the scheme of my electrical panel.


This is the Victron schema:


To avoid having to comply with the 1:1 rule, by which I would need two Victron to support the 8000W of the panels, I want to put a single Victron MultiPlus II 5000VA. So that if the street grid goes down, even if the panels stop producing, I still have light at home. It is something punctual that happens at most twice a year and only for a few minutes. I don't want to separate in Loads and Critical Loads, I want that all the house will be power by the Victron.

I have been told that I have to connect the Fronius to the AC-IN of the Victron and in AC-OUT connect the house, as if the whole house were critical loads.

How would the connection be made, can anyone help me?

timmy asked
mr-manuel commented ·

2 Answers

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
nickdb commented ·

3 Answers

Victron 3 Phase 15Kva Quattros with Fronius 27 eco on AC output HOW DO I USE 1PHASE GEN ON SYSTEM

Hey guys i really need some expert advise here

I have got 2 clients

3 x 15Kva Quattros in 3.Phase

1 x 27 Kva Fronius Eco AC coupled

2 x 450/100 Mppts

In South Africa with Loadshedding and line fees

we opted to shift to Utility Prepaid 50 Amp 1 Phase as this is all that is avaliable on prepaid

AS we have had multiple systems before we use 1phase input as backup with 3 phase system we add the 1 phase input on inverter 1 as a Generator and this closes a contactor this works fine if there is not a fronius in the system and only MPPTs but if we try to do the programming with a 3 phase fronius it takes off the PV assistant (my idea was to use the contactor to switch to grid 1 phase but also kick out the fronius for the time to charge the system

I know i can add a additional charger or inverter to do this but its expensive so i need this to work

Any ideas or anyone that has done this please assist

@Guy Stewart (Victron Community Manager) if there is somebody that can help me it is probably you or @mvader (Victron Energy)

Thanx in advance

Werner Lombaard


werner-1 asked

0 Answers

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


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