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AC PV Coupling

is it possible to run a 1Ph PV inverter in frequency shifting on a 3Ph Victron Quattro system?


I have got an off-grid 3Ph 400V system comprised by 3x 15kVA Quattros and would like to install a Fronius 1ph Galvo PV inverter. Is this possible through the PV inverter support assistant? or mustit be a 3ph pv inverter?

Also, taking into account that for physicals reasons, there can not be modbus communication between the Fronius and the GX device, the system should work autonomously in frequency response.

Jesus Mazo asked
Jesus Mazo commented ·

1 Answer

AC coupling Multiplus II start up frequency

Have a problem with a multiplus II on start up with frequency, if there is solar capacity and grid drops out with charged batteries the ac output shuts down, which is understandable no where for power to go. But when it restarts it starts with frequency at 49.99HZ, which means that solar will start up at full capacity again and with no were for power to go (if no load) then ac cuts out again this will happen sometimes, but sometimes the multi will start with frequency @ 50.5HZ (this would vary on systems depending on what solar inverter is set to) and when it restarts in this way there is no issue with the solar starting off at low power output and the system does not drop out.

Is there a way to make the multiplus start at a higher frequency, this would allow solar to start off at a low capacity and build up, instead of dropping power out and back in, until it can settle itself down. It seems to me that the ac coupling on the victron is a real challenge from what I have read.

Any ideas?


sales asked
Paul B answered ·

1 Answer

AC Coupled inverter on AC-OUT with export limiting to the INVERTER!

I am busy with an off-grid installation that has a Goodwe GW15KN-DT PV inverter on AC-Out of a set of Quattros. The PV Inverter assistant is configured and frequency shifting works as expected as the battery approaches full. The Goodwe is supposed to be VDE4105 compliant and the suppliers assured me before purchase that it was able to reduce power in response to frequency shifts. In practice the Goodwe does not respond appropriately to the increases in frequency. It does cut-off once the threshold for frequency error is crossed. But it does not throttle back for lower frequency increases.

A long period of troubleshooting with the suppliers and including Goodwe HQ has not produced results beyond establishing there is a problem and that a firmware fix is somewhere in the pipeline. They are not able to provide any information on when this may be.

In the meantime the Goodwe and it's array sit idle!

Would it be possible to implement the export limiting function in the Goodwe such that it will not export back in to AC-Out on the Quattros and only follow the loads on the distribution side? i.e. the CT clamp is positioned between the PV Inverter and the Quattros.

I understand that if this is not 'a very bad idea' for technical reasons then the Goodwe would not contribute to battery charging. This would be acceptable at least until a more robust solution is devised by Goodwe.


rodgerd asked
rodgerd commented ·

0 Answers

MultiPlus-II -24 3000 not charging

Hi Everyone. When the Multipluss II is conncted to the mains, the 'Mains On' light flashes green. According to the manual, this mean that the AC input is switched through. The AC output current is equal to the preset maximum input current. The charge current is reduced to zero. Can you please explain in laymans' terms why this is happening and how I can fix the problem?



Jonathan Phillips asked
Jonathan Phillips commented ·

1 Answer

MyPv Ac-Thor AC coupled off-grid system settings

Hi All,

I'm planning off-grid system with PV and wind turbine. Based on the initial research I think that MyPv Ac-Thor is able to work as a dump-load for the wind turbine. I would also like to include a hot water boiler as prime excess power load.

I found this page but there is no information about how to configure AC PV Inverter.

If I "define Frequency start value 50.1Hz and the Frequency end value 51Hz" in Quattro and Ac-Thor my guess is that AC PC inverter should have some offset e.g. start 51Hz end 52Hz. If all three have the same range PV Inverter will lower it's output so there won't be excess power for Ac-Thor, am I right?

I would like to use dump load only for wind turbine after boiler reaches target temperature. I'm not sure if this can be achieved using only one Ac-Thor.


Two units with following configuration seems to make sens:

1. First Ac-Thor 50.1Hz - 51Hz -> hot water boiler

2. AC PV Inverter 51Hz - stop

3. Second Ac-Thor 51Hz - 52Hz -> dump load for the wind turbine

Am I missing some better solution?

Thanks for your help!

dyju711 asked
thomasw-1 commented ·

1 Answer

Victron QUATTRO 48/5000VA with SMA 5000TL Inverter in Island mode

Hi, I have an existing grid-tied SMA inverter (SMA 5000TL) and 2 strings of 13 panels for total of 6.5kW. I want to add storage and am considering the QUATTRO with 4 x Pylontech US3000 batteries (@48V nom).

The main aim of the exercise is to be self-sufficient in case of extended/indefinate grid outage. I am no expert, but my reading suggests that the Victron QUATTRO would provide a mini-grid on the AC-OUT-1 and that the SMA solar inverter would run 'normally' on this channel regardless of whether the grid was connected or not.

Assuming that the above is correct, would the SMA inverter connected in this way be a stable and reliable configuration. I ask this because I have read some posts/articles that indicate that there are situations where the inverter may go over-voltage and shutdown the QUATTRO.

Is this a potential problem, and what would be the recommended way to deal with this?

Note, the loads would include 1000W and 1500W pumps (bore pump etc), inverter aircon, fridges and freezers, lighting and misc.

thank you,


rrroonn asked
chrisallo commented ·

3 Answers

Easysolar II GX - Grid parallel on AC-IN with ESS does it work?

Hi all,

Has anyone managed to do this with an Easysolar II GX and the CT with nothing connected to AC-OUT-1 or AC-OUT-2???

I have an Easysolar II GX set up in grid parallel mode on AC-IN (as pictured below). It is configured with ESS assistant and the Current sensor on my mains (I am using the AS/NZ grid setting). I have other Grid Tie inverters in parallel with AC-IN. Basically using the Easysolar as an AC coupled storage system (store energy in battery when excess solar and use energy from battery when no solar).. The system works perfectly except it keeps failing during the charge cycle typically around 90% SOC. I have also noticed that the GX part of the Easysolar keeps power cycling.

Has anyone experienced this failure? The symptoms are the Multiplus supplies loads perfectly and charges perfectly except when the "GX device" loses visibility of the built in Multiplus (sometimes it also loses the built in MPPT which I am not using and the internet connection). At this time the GX remote console can't see the Multiplus or any ESS configuration so it just turns off and never recovers until I reboot from the remote console OR switch off with 3 position switch on inverter. When rebooted it works again perfectly but rebooting every day once or twice is not practical.

I suspect a fault or firmware issue or memory leak or something wrong with the charging algorithm???

Any ideas or help would be awesome, things I have tried already:

Turned on DVCC, temporarily fixes the issue for 24hrs then goes back to failing on charge cycle

Connected by ethernet not wifi, didn't fix the issue

Set inverter up from scratch again, didn't fix the issue

Did all firmware updates again (with GX device disconnected), didn't fix the issue

This is what I have except nothing connected to the "No break loads". My battery is just AGM with no smart BMS etc.


Thanks in advance


on2itmaclennan asked
Daniël Boekel (Victron Energy Staff) commented ·

2 Answers

multiplus 2 and ac coupled pv inverter- behaviour in grid failure

If a multiplus 2 is configurated with ESS, and a AC coupled ABB PV inverter is connected. What will happen if the grid fails, but the batteries are full, and the PV inverter is inverting?

I suppose the PV inverter must have some sort of cut off?

jejochen asked
Vangelis Beligiannis edited ·

2 Answers

AC coupling Solaredge - LG batteries in visualization

Hi Solarists,

I'm building AC cupling to my SolarEdge system. I have a SE 5000 HD Wave with an LG 10H battery. I want to add Multiplus II and a pylon battery, like AC cupling. My question is whether the LG battery will be visible in the GX visualization or on the portal? Thanks

beny asked

0 Answers

Can I use multiple em24 energy meters?


is it possible to use a couple of energy meters at the same time, i would like to have 1 for grid in/out and i would also have to have 6 for PV's which are connected to AC OUT on Victron Quattro.

paulmarinas asked
ossi answered ·

2 Answers

Fronius error state 105 ac-coupled system with victron

Good day

I have recently installed a Fronius primo-6 together with a quattro 48/10 000 in an ac-coupled installation

the system works perfectly when the main switch on the DB board is off (thus making the system completely off grid) but when the Main switch is switched on the fronius gives me an error state 105 when reading up about this it means the ac grid frequency is to high... i tested the frequency from the grid and it jumps around 51Hz to 52Hz which should be will within the fronius parameters so my question is has anyone experienced something similar are there settings that are not correct on the fronius any help would be appreciated


hannu asked
Vangelis Beligiannis answered ·

1 Answer

AC-Coupled system with Energy Meter, how to secure communication?

Attached the configuration I would like to achieve.

This is a three-phase house fed from an unstable grid. However we have 3 x Multiplus 48/5000VA available for off-grid . To limit Multiplus outputs to max power, we would like to use gridparallel functionality of the multiplus, meaning feed the loads from ACin as far as EnergyMeter allows. We want that the PV Inverter continues working during grid failure.

My questions are following :

1. Is this configuration ok to work with ? Will 'Loads 2' also profit from the PV Inverter and the charge controller ? I guess with ESS , it should be possible...

2. Can CCGX see both Energy Meter and the PV Inverter(Fronius Symo) over the network, assuming I will use EM24 as energy meter ?

3 In case of a long blackout when also the dsl provider cannot give internet connection is there a problem with the communication of ccgx with the PV Inverter and the Energy Meter ? How to prevent that ?

bulraydin asked
bulraydin edited ·

0 Answers

AC coupled battery backup


I am putting up an Enphase micro-inverter based PV system (10kW) and I'm trying to work out an AC coupled battery backup system. I've read this guide, and want to make sure I'm understanding correctly.

Could someone please confirm/deny the following points/questions:

--based on the VA rating of the Quatro or Multiplus, I would have to split the PV output in to two groups....for the 8000VA Quatro for example, I could have up to 8000 watts of PV connected to the Quatro and the other 2000 watts would have to be connected directly to the grid

--for that same 8000VA Quatro, I would need a minimum of 570amp hours of 48v lithium batteries....I could add additional batteries to increase capacity if desired



kgmoney asked
kgmoney answered ·

1 Answer

3 phase Microgrid with Fronius (AC and DC coupled) Output 2

I was wondering how the Output 2 on a Quattro or Multiplus 3 phase micro-grid with Fronius works. If the Fronius is on Output 1, how do the Victron inverters make Output 2 operate? Does it operate as it normally does in a normal three phase installation without Fronius?

james asked
james-davy answered ·

1 Answer

in ESS system the Pv Fronius Inv. feed in the power no charging the battery ..

Hi All .

I get a problem with a below system three phase Victron + Fronius running in ESS .

The power from Inverters don't charging the baterii , the power go to feed in to Grid ...this Ess working right. the Et340 need to be update ?

I try al the configuration from Ess ,but no succes .

Please help to me with a right asasinat settings for this configuration...














Gabriel Tanasescu asked
Gabriel Tanasescu commented ·

1 Answer

Calculation of PV and inverter power in an AC coupled system
Hello community, can someone help me calculate the wattage of solar panels to be installed in an AC coupled system please? I have three Quattro inverters of 10000VA each in a three-phase system of  30.000VA, can I use a Fronius Eco 27 with 72modules of 400Wp each (28.8KWp)

Deutch asked
Alexandra answered ·

1 Answer

Easysolar 24/1600 PV-Module

Wir setzen 4x qCells - Q.Peak- DUO-G6 345 PV Module ein.

4x 345 W P // 10,73 A I-SC // 40,49 V U-OC // 10,22 A I-MPP //

33,76V U-MPP// 1000 (IEC) V U-SYS

Wir setzen Easysolar 24/1600 ein.

Wie müssten wir die Module richtige angeordnet werden ?

Wir würden gerne 2xModule in Serie und 2x Parallel schalten,

diese über DEHN-Überspannungsschutz gehen und am Klemmkasten zusammenschalten

und als 1 String anschliesen.

Was ist das optimaleErgebnisse zu erzielen?

Oder alle 4 x Serie ?

thomas64 asked

0 Answers

Smart Solar MPPT 100/20: Connect 48 battery instead of PV solar panel; possible?

I happen do have a large 48V boat battery and wonder if that could be used to load/extend the capacity of my 12V Battery through the Smart Solar MPPT 100/20 by connecting the 48V battery to the Smart Smart Solar MPPT 100/20’s PV input.

Obviously the 48 battery is capable of delivering more than the rated 240W.

The handbook states, that the Smart Solar MPPT 100/20 may be destroyed if the connected solar panel delivers more power than the Smart Solar MPPT 100/20 can handle. Would it also be true in this configuration? What could I do about it?

From what I read in other posts it should not be a problem as long as the voltage limits are kept.

Firmware has been updated 1 Month ago.

joerg-eichenau asked
wkirby commented ·

1 Answer

how to connect different pv with different WP and mppt point to my solar set?

Hi all, I'm new here and looking for some answers....

I'm currently using 2 solar sets for my house truck.

The first set is my household set, currently one pv combination (3x monocristal 210Wp parallel connected) which is connected to mppt 100-50 also with 4 new agm batteries 24v parallel 145Ah each battery. I have victron inverter 24v500W and all guarded by my BMV (with apps for bmv,mppt 2x, and inverter) also I connected directly to the batteries a cheap nonsinus inverter (chinese) of 1500W (i have 230VAC fridge 150W which needed some more peakpower).

My second set is a seperate victron set for my lead - start batteries. 2 panels with 75-15 victron mppt loading start batteries ( they only use drop load, since batteries stays almost full.. its a bit overdone, but want always to be able to drive when needed).

When turned one the generator/AC from the net, I use a victron centaur 30A 24v to charge my household batteries and a 10A 24v mastervolt charger to charge start batteries.

I'm here at this forum because I want to figure out how its possible to use 2 or 3 DIFFERENT sets of pv (perhaps connected to a new easysolar 24v 1600VA, co combine all the seperate parts into one. BUT, the 2nd and 3rd PV set will be another type of panel with different mppt point and Wp..

So my first question is to figure out, how to use max. capacity of solar panels in different sets, connected to a MPPT, or easySolar. My dream solution is to use 3 different pv sets,connected to a Easysolar, which load both household set and (dropload) my startbattery. I want to ask you guys if this would work and if that means that my victron centaur, my existing mppt 100-50 and my mppt 75-15 become obsolete.

What I already found out here is that each input on the easy solar is protected 30A. But what happens between the 30A connections and the mppt? are the cables just connected together in 1 PV connection at the internal mppt from the easysolar and does this give space for different pv sets?

And second question, is it harmfull that i put a second nonsinus inverter directly to my batteries? The batteries are almost new (bought last summer) and i don't want to destroy them. but i realise with almost no sun, the batteries run empty in 2 days.. which is too fast..

i hope my question is a bit clear and hope to find some tips and tricks to tackle this problem!

thanks already! Ropski. :)

ropski asked
Matthias Lange - DE commented ·

3 Answers

Common Neutral in Domestic Situation

Hi All,

I need some solid engineering input on this question of making input and output inverter/charger neutrals common. I have seen the Common Neutral thread which is for a different application. This is a static application situation - a problem I have been battling with for over 6 years on all my projects.

It is essential to state the two key problem causes and why they are not solvable:

1. Our municipal grid has been degrading severely over the last 30 years with poor maintenance causing neutral disconnections and ground-neutral bonding issues on the utility/transformer side. This is getting worse due to utility having little finance and incompetent maintenance staff.

2. House wiring standards are not adhered to in many site cases meaning joins on neutral in ceilings/conduits for multiple electrical circuits. Or missing neutrals. To fix this (compliance issue) takes up a huge amount of time which customers are mostly not willing to pay for so I have found myself working hours, days, weeks and months for free to sort out these issues. Why is this a problem? Apart from the obvious electrical problems and neutral overloading, in my country customers cant afford to go off-grid so we split the house wiring into "inverter powered" and "grid powered" circuit (btw: we have daily power outages everywhere). Which means inevitably we will have a neutral fault or a common neutral somewhere in the wiring due to these non-compliant situations. So it may be worth common-ing inverter and grid neutral in the main distribution to "draw" the connection off house wiring - just a thought as the worst thing is to power a circuit without a neutral - our utility conditions has done us the honor of doing the "hands-on" test for us - to the detriment of equipment or lots of SPDs.

So my question: Is there any electrical compromise I can look into? - to stop me from sponsoring customer's compliance because of the nasty 80% of electricians who cheat and make lots of money.

Maybe some specific protective device or solution including common neutral, a specific SPD? some RCD that works -

* a 30mA RCD is not an option - electricians bypass them because of continuous tripping.

* off grid not an option as customers can't afford it.

* redoing site wiring not an option because customers can't/ don't want to afford it

* me quitting the business is a less than ideal situation as with 90% unemployment rate in my country other lines of work are just as difficult.

So to all the engineers out there who like solving problems please HELP! :D

P.S. I'm an Electrical/Electronics Engineer with more knowledge in Electronics than Electrical Power - I have fair experience with the effect of surges and earthing issues in electronics ;)


kenyon asked
Keith Arnold commented ·

3 Answers

MultiPlus-II with AC-Coupled Inverter and Cerbo-GX not showing negative load on AC output for AC PV Inverter

I have a MultiPlus-II 5kVA running in an offgrid system with all Loads connected to AC Out 1
The batteries (Pylontech) are mainly charged by a victron Mppt, but in addition I have an AC-Coupled PV Inverter (Solax X1-Mini) connected to AC-Out2.

In the MultiPlus-II I have an assistant installed which switchs AC-Out2 on and off by the current state of charge, because the very simple inverter has no options to reduce power output (e.g. by changing the grid frequency).

Later I've installed a Cerbo gx and enabled DVCC, from that moment on, the MultiPlus-II didn't light up the Charging LED's anymore and on the Cerbo GX I only see 0W power consumption on the AC side, when the MultiPlus-II is charging the batteries.

With ve.configure or with the Grafana-Dashboard soultion instead I can see e negative value for the AC-Out power.

Is there an option to show up these negative values on the cerbo-gx as well?

robtor asked
robtor commented ·

1 Answer

Off Grid Installation AC Coupled Fronius Disconnects with Back Up Generator Is Switched On


I have installed Quattro 8kva with 8kW Fronius AC coupled with a CCGX 800Ah of batteries. It is an off grid installation with PV inverter assistant on. When I switch on my generator and the Quattro synchronises with it the Fronius inverter disconnects and says error code 107 which meant no grid.

My generator is 4.5kVa but the wave form is poor so I have limited the current to 13amps and I have used the Weak Ac function

From what I have read about the off grid systems in victron literatureI thought that the Quattro would control wave form so the Fronius and Generator could both power the loads and charge the generator.

But from reading other posts it seems the Quattro is just passing the generator AC frequency through and it’s too messy for the fronius to sync.

Is there a way to allow my generator and fronius to work?

tunde-olaoye-1 asked
jon-lowbank answered ·

4 Answers

Can I use a Multiplus the same way that a Tesla Powerwall 2 works?

A Powerwall can be connected to existing grid tie inverter regardless of the PV array size or the inverter size (no 1.0 factor rule).

A Powerwall can be connected to a single phase of a three phase system.

If the grid fails, the existing PV array continues to provide the battery with energy.

Can a Multiplus meet all of the above criteria for one installation?

blue-sails asked
Matthias Lange - DE commented ·

2 Answers

Can I go from AC coupled PV to not AC coupled PV and back with the switch?

At the moment my on-grid inverter is connected in front of Victron system.

This on-grid inverter is not on the list of inverters recognized by Victron and does not react to frequency shifting used by Victron.

I would like to be able to move this inverter from not AC coupled to AC coupled and back with the switch.

Can it be done?

The reason for it is that, when inverter is AC coupled and Victron fails, I can use a bypass switch to bring power my loads. When it happens my PV inverter is also disconnected from my loads.

In this situation I would like to "move" my PV inverter to AC input side and be able to use its production when grid is present.

The other reason has to do with my grid operator.

They are preparing to force the owners of PV systems, connected to the grid, to turn the PV system off on their request, or even do it automatically by the signal from the grid.

In that situation I want to have an option to go off-grid rather that turn my PV off.

marekp asked
marekp edited ·

0 Answers

Should a/c coupled charge a battery in ESS mode?

Easysolar II GX not charging from a/c coupled PV. How can stop it exporting to the grid and make it go to the charger. Setup is ESS optimised with battery life using Pylontech US2000 and a current transformer on the incoming grid.


gat asked
Alexandra commented ·

2 Answers

AC Coupling with non-Fronius inverters and export power limiting

Hi All,

Here in South Africa we are more often than not, required to prevent power being exported beyond the Meter (Grid).

We often encounter homeowners who have already invested in a solar power system, with some form of grid-tied inverter installed.

The typical upgrade involves installing MultiPlus or Quattro Inverter/Chargers with some form of lithium battery bank.

The question arises with regards to how we incorporate the existing grid-tied inverter?

If it is not a Fronius inverter, then we cannot use the "Fronius Zero Feed-In" functionality through using a single energy meter (Carlo Gavazzi ET112 or ET340).

If we retain the existing grid-tied inverter's export limiting device (current sensor or energy meter), and continue to implement an energy meter for the Victron system, then how should it be set up? Which device should be installed first in line? Should we set a buffer/threshold on one of the systems to ensure that they do not compete to achieve grid-power = 0 (or other set point)?

I foresee that the two different export limiting control systems will compete against each other and may result in instability and/or poor performance.

Any insights into this?

Nicholas Herbst asked
mike-moody commented ·

2 Answers

Cyrix ct120 + Blus smart IP22

Bonjour, Dans mon van j'ai une batterie de démarrage et une batterie auxiliaire reliées par un coupleur-séparateur Cyrix CT12. J'ai installé un chargeur Blue smart IP22 à ma batterie auxiliaire, quand elle est chargée à 100% je pensais que le coupleur permettrait au chargeur de charger ma batterie de démarrage mais il ne le fait pas. Avez-vous une solution ? Bonne journée à tous Arnaud

devillers asked
Stef edited ·

3 Answers

Is there a way to test the frequency shifting that controls AC coupled inverter?

I have a on-grid inverter made by Spirvent.

Unfortunately this maker does not exist any more and I cannot get any reliable info about it now.

It still works so I would not want to spent money on the new one, just to be sure that it will work in AC coupled configuration, because it is on the Victron approved list.

Is there a way to test this Spirvent reaction to frequency shifting other than connecting it on AC out and waiting for the moment that MultiPlus-II will need to lower inverter output and starts shifting the frequency?

marekp asked
marekp edited ·

2 Answers

Sub-50Hz compensation in PV-Inverter support

PV Inverter support uses frequency shifting to steer PV Inverter output on the AC branch.

This works very nice and reliable with Fronius inverters in our nstallations.

However, this frequency shift works only in the 50Hz+ range, there is never a compensation below 50Hz:


Now all devices in the microgrid that take these 50Hz as source for their internal clocks (actually quite a few do - e.g. microwave oven clocks) start to get ahead of time noticeably within a month.

Wouldn't it be possible to implement a sub-50Hz compensation in the nighttime to counter the effect that accumulates over daytime?

As soon as e.g. the Fronius switches off for the night, there shouldn't be any adverse effects to lower network frequency to 49.5 or so.

According to our measurements, the clock skew can be as much as 0.8% per day - so I'd really appreciate if the assistant had some compensation measures built-in.

PS: If I choose "50Hz" as tag, it gets converted to "EasySolar All-in-one". ???

petajoule asked
Guy Stewart (Victron Community Manager) commented ·

0 Answers

AC Coupling with Autotransformer


I currently have a 15kw Quattro with a 100A Autotransformer on AC Out 1 to provide power to a distribution panel. I want to attach my solar PV to AC Couple the system. The Quattro and battery size both satisfy the factor 1 rule... What I'm wondering is if I can I attach the PV between the Autotransformer and distribution panel? or does it have to be attached in between the Quattro's AC Out 1 and Autotransformer?

Thanks for any help.

bishop8 asked
wkirby answered ·

1 Answer


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