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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

Quattro and Fronius Gen24

Has anyone added fronius Gen24 with Highvoltage battery storage to a Quattro system

I have four 10kw Quattros 48 volt 130kwh lithium and want to add Gen24 and lithium

Frank asked

0 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 https://community.victronenergy.com/questions/133217/quattrobydgxfronius-high-voltage-alarm-when-reachi.html) 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

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

Cerbo Gx does not recognize Fronius Gen24 inverter

I have a simple ESS with a Fronius Gen24 PV Inverter on P1 and the MP2 also connected AC in to P1.

After activation of modbus UP access in the Fronius console, the cerbo displays a Fronius inverter but shows "unknown inverter" and also shows it only connected with one Phase. Because of that the values on AC Loads are always wrong, if you add the charging power plus the AC loads you get more than the PV is currently delivering.

How can I make the cerbo detect the correct Fronius type?

Cheers Thomas

escamoteur asked

0 Answers

High charge current alarm

Hello, hoping someone can advise me with a High charge current alarm.

I have an off grid system

Fronius inverters

Victrion multi plus

and Pylontech battery's (30kwh useable)

The problem I am having is when the Batteries are full and my inverters are restricting the power off the roof until a large load is being used (e.g kettle) then the inverters step up to provide for the load.

Once the load is switched off the power is diverted to the already charged batteries causing "High charge current alarm"

any help would be appreciated (-:

alexanderr asked

0 Answers

Differing Loop Impedance on Quattros for 3-phase system causing Fronius malfunction?

Problem: Fronius Symo 15.0-3-M stopped functioning.

Status: Fronius Reporting ERROR 453

Grid Voltage and Power Module Discrepancy


3x Quattro 10KVA

1x Symo 15KVA AC-Coupled on Quattros AC-out

We have tested loop impedance:

L1 Quattro 5.0Ohms

L2 Quattro 4.8Ohms

L3 Quattro 0.75Ohms.

We are concerned that the difference in loop impedance may be causing the malfunction of the Fronius SYMO. We are also concerned that while replacing the SYMO may provide a temporary resolution, the difference in loop impedance may cause an eventual failure in the new SYMO.

It is to be noted that the L3 Quattro was replaced within the last year.

L1 and L2 Quattros were purchased and installed around 2015.

Your expert knowledge, comments, or advice is appreciated,

sparkpoint-solar asked

0 Answers

Charge batteries from the Fronius inverter and Victron gives an increase in frequency and cuts off

Good afternoon! It is possible to charge batteries from the sun from the Fronius inverter, and Victron gives an increase in frequency and cuts off this possibility.

How to fix it?

more than 90% of the victron charging does not work.



Admin AvanteComUa asked
Admin AvanteComUa edited ·

0 Answers

Fronius firmware Update


Has anyone tried the latest firmware for the Primo,s in an AC coupled off-grid system?

The latest version is (fro33350.upd).

Interesting to see how its going to perform in regards to the (Flickering) issue that sometimes seems to be an issue. I also noticed in the change-log that they mentioned that there is some changes in the MG50/60 off-grid system setup. Does any one know what they are?


Dave Rae asked
scraggs commented ·

0 Answers

Cerbo mixing up measurements , Fronius continuously throttling

Hello everyone,

we have a special case, where I could not find any answer in the community, hence decided to write here , maybe somebody has a solution.

Following is the setup :

1. 12 x Quattro 48/15000

2. 6 x Fronius Eco 27.0

3. 4 x Smartsolar 450/100

4. 500kWh Pylontech batteries (US3000 )

5. Cerbo GX + Touchscreen

Fronius inverters are connected to AC-Out 1

Grid is connected to AC-In 1

Communication of Cerbo and Fronius are over LAN

All firmware is updated,

ESS asisstants are loaded to all the inverters. Grid can only give 100A per phase, hence on quattro's also the input current is limited to 20A each, to avoid overload on the grid.

System works fine during off-grid (when grid is shut down)

as soon as grid is connected and the power generated by Fronius exceeds the power requested by the loads, cerbo starts mixing up data. For example it suddenly shows no loads at the output for a few seconds and this causes him to send the command to Fronius inverters to step down with the production , although in reality the loads are more or less constant and battery not yet full.

This problem repeats itself as long as the PV generation is higher than the loads. Fronius inverters try to ramp up but then they are throttled due to false measurements. This is quite unhealthy and very inefficient.

Currently I have disabled ESS , instead I have uploaded the PV Inverter Support and the general flags for AC ignore assistants , however this is not a good solution , as the customer would like to set the SOC levels himself.

What could be the reasons ? Where does cerbo get the measurement data from ? Could the cerbo be defected or somehow slow in reaction / calculation ? or problem somewhere else ?

Would appreciate your comments very much.

Best Regards

bulraydin asked

0 Answers

Fronius Modbus "float" setting also working?


i just started my Victron installation for test purposes, and have not set up my Fronius Modbus connection correctly.

It is still on Modbus TCP "float" instead of the Victron-required "int+SF"

I wanted to change this later.


i can see my Fronius Inverters and all its data on all Victron Display, VRM, etc.

Seems to work fine.

So... is "int+SF" really required at all? Or does it work with "float" also anyhow?

If so it would be nice, because then i would not need to change all my other external modbus datalogging, etc. that already exists

Or are they some specific registers, that only work on "int+SF" correctly?

pedaaa asked
pedaaa edited ·

0 Answers

Fronius disconnect loop (Quattro in ESS and Pylontech batteries)


I have a Fronius Primo 8.2-1 connected to two Quattros 48/5000/70-2x100 running in parallel. In addition, we have two SmartSolar MPPT 250-100 chargers and a mix of Pylontech US2000, US3000 and US3000C (12 batteries in total - with the US3000C as masters and the rest as slaves, with three 120A rated cables going from the Lynx to the batteries, distributed as equally as possible).
The Fronius is connected to AC OUT 1, setup is MG50 and in ESS the frequencies are as recommended by Victron: Start 50.2 Hz, Minimum 52.7Hz, Disconnect 53.0.

In Venus, under Pylontech battery, the parameters are identified as follows: Charge Voltage Limit 53.2, Charge and Discharge Current Limit 335.0 A.


When there is enough sun, I get 10kW from the two SmartSolar chargers and around 6kW from the Fronius. Problem can be spotted in this graph, usually at ~11kW sent to the Pylontech batteries (anything above 220A for more than 10 seconds), the Victron raises the frequency and the Fronius gets disconnected with error 105 (too high frequency). The Victron then drops the frequency back to 50Hz, Fronius spends some time and does its checks and after a while its connected again, rinse and repeat.

When there is high load on the house, the Victron leaves the Fronius to work at its full potential, sustaining 5.5-6kW for as long as there is enough sun. So my guess is that the reason for this behavior is somewhere between Victron and Pylontech.

Does someone have an idea why this is happening, what can we test and do to solve this?

Thanks in advance.

Kitaigorod Alexandru asked

0 Answers

Generators compatible with Fronius grid tied inverters.

We have a Fronius grid tied inverter connected to the output of a Quattro. Fronius grid tied inverters have a shutdown facility which utilises frequency shifting the ac by 1 Hz.

Suppose we have an ESS with a Fronius, Quattro and a generator. If the generator kicks in and the frequency is not exactly 50 Hz, the Quattro will frequency-track it and in doing so inadvertently shut off the Fronius grid-tied inverter.

Do we have to purchase a super-stable generator with exact 50 Hz frequency in order to prevent conflicts between the frequency of the generator and the grid-tied inverter?

Barry Clark asked

0 Answers

VE.bus voltage high and not stable causing output voltage to be unstable and trip

We have a 5kva MP setup with a 5kw fronius grid tie inverter.

We see the ve bus voltage to be very erratic during sunny hours of the day when the battery is full.

The battery voltage is stable but the VE.BUS voltage go as high as 64Vdc, causing a output voltage imbalance and the inverter trips out.

It is a 5kwh BSL battery with comms to the gx device.

What can cause this issue?dc bus.png,



martin-van-biljon asked
martin-van-biljon commented ·

0 Answers

Two fronius inverter connected to AC-OUT: 1.0 rule

Hi together,

I have two fronius Symo 15kVA with 36.5 kWp combined PV panels, currently connected at AC-IN, so they will be shutdown during grid outage.

In addition I have 3 Multiplus-II 3000 with 8 Pylontech US2000 48V and 4kWp via an MPPT-RS.

Everything is 3phase in my household (heat pump, oven, cooking, wallbox...).

If there is a long power outage (days to weeks) I'd like to have the possibility to rewire the fronius inverters to AC-OUT and reconfigure them to MG50 frequency shifting to also use the power that they generate.

Now my question: is it possible to use this configuration if I limit each fronius to max 4.5kW via Fronius Grid configuration? This should then be 2 x 4.5kW = 9kW distributed over 3 legs. So it should still match the factor 1.0 rule because there is never more then 3kW on AC-OUT on each of the Multiplus-II 3000.

Will frequency shifting still work in this configuration?

christoph-dunker asked

0 Answers

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