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AC PV Coupling

AC Coupled PV Fronius 8.2 with a Quattro 15kv too slow to throttle

Quattro 15kv, Fronius Primo 8.2 with 7900w PV, 3 x Kilowatt labs 3.55kw modules, 2300w PV running thru a 150/70 Victron charge controller, Off Grid MG50

Maximum charge voltage of the modules are 54v and if they are fully charged and the AC PV is supplying 4000w with 4000w Quattro loads and the loads drop off, The system is way too slow to react in shifting the HZ to throttle the AC PV. (3 to 5 min)

I had to reduce the max charge voltage of the modules via the Quattro to 53v to allow a full volt of slow down time. Seems to be working at the moment.

Is there any way to increase the speed the Quattro ramps up the HZ to throttle the Fronius?

(I’m using the standard settings in the VE configure assistant to control the Fronius)

Should I Adjust Victron HZ shift values in the inverter to suit the Fronius values?

What are the correct Fronius Primo 8.2 inverter HZ shift values ?

greendovefarms asked

0 Answers

AC-coupled PV. Off-Grid. Fronius PRIMO with Victron Phoenix?


Simple question but haven't found the answer it possible to combine a Victron Phoenix Inverter 48/5000 with a Fronius Primo 5.0 for an AC-coupled PV installation? I have no need for a Victron charger as I am off-grid.

stijn asked
greendovefarms edited ·

4 Answers

How can I share 3 x AC coupled Victron systems in a microgrid?



I have 3 installations in my home in AC coupling. The grid is here only when the SOC is under 50% controled by CCGX.

When i don't go to the Works in week end, the batteries are Full and the Labo are Full too and i need energy for my Home and sometimes the Soc is under 50 %, i don't want to take the Grid.

When i go to Works or Labo in the week, my Home is Full and i need energy for Works or Labo. I always disconnect from grid when the SOC is upper than 60%.

How can i share this Full batteries beetwen Home Works and Labo ?

How can i install and configure to make a MicroGrid ?

Where i can connect the 4kWc ?


maitresyoda asked
Paul B answered ·

1 Answer

Extra Grid Meter for PV Inverter output measurement?


I have following components

  • Victron Multiplus
  • ET112
  • Cerbo GC
  • 5 EVT300 with Solar Panels
  • 3 pylontech batteries

the ET112 is installed on the AC Input side of the multiplus, my AC Loads are connected on the AC Output 1 side, on that there are also the 5 EVT300 with Solar panels


Is it possible to addPV Inverter Power widget in that graphic ?

Or do I need a second grid meter ? Or do I need to installe the ET112 on the AC Output side ?



midmaik asked
Paul B edited ·

1 Answer

Huawei 36KTL and 3 x Quattro 8000 Chargers

Good Day

I have 3 x Quattro 8000 Inverter Chargers connected to a Huawei Sun 36KTL Grid Inverter. The panel sizing only allows for a peak of 24,449KWP.

Is it possible to AC couple this system?

nick-b1983 asked
Alexandra answered ·

1 Answer

False overload alarms

Good day,

I have a AC coupled 5kW system.

Every now and again, during a power outage, I receive a overload alarm and once a system shutdown when the system switched over to inverter power. The thing is, there was no loads to justify the overload.

I have noticed during the triggering of the outage, it takes some time for the grid inverter to react and that value that was feeding back into the grid starts to show on the load-side.

I am just wondering, due to the time delay, the system sees the generation in the load and thinks it requires the batteries to meet that load, which is in fact the generation.

I have also seen this on a few of my systems and wonder if anyone else has experienced or noticed this.


danepb asked
warwick commented ·

1 Answer

Best configuration for Narada 48NPFC100 in Multiplus II

Hello, I need help to configure a Multiplus II 3000 with 2 Narada 48NPFC100 lithium batteries in a PV system with 2 SMA Sunny Boy 1.5 in an off-grid system. The system is working fine and charging the batteries until for some reason unknown to me, the Multiplus raise the frequency and shuts down the SMA inverters (also the electricity in the house) even when the batteries are not fully charged. My supplier in Chile for both Narada Batteries and Victron Multiplus doesn´t answer my queries and I don´t trust in the batteries and charger configuration (VEConfigure and ESS) that the supplier gave me earlier. If more info is needed please ask me for it. Any help will be very appreciated.

Info from last 3 days:






PS: may be @NicoV or @Daniël Boekel (Victron Energy Staff) can help me? Thanks!!!

santiago-mackay asked
santiago-mackay commented ·

1 Answer

AC-coupled PV 3-phase with pylontech


I'm currently design my ac coupled system (without grid):

-3x10kW fronius symo (1pcs with data manager and 2 pcs light version)

-3xquatro 48/10000 for 3 phase config

-4x4banks US2000-2.4kWh pylontech battery bank (4pcs 48V parallel for 1 conection / 4 connections in total)

-Venus GX control

My questions are:

1. For Fronius inverter, it's a must to have datamanager on each inverter? Or I can use protocol with 1 master with datamanager and 2 slaves.

2. Can I use quatro inverter to charge the battery bank when I have power from Fronius inverters? Or, do I need MPPT DC coupled system mandatory to change the battery bank?

3. Concerning CAN bus from Venus GX device, will be possible to communicate to all 16 battery module? Or I need another device (in this case, which one)?

4. also, will be a problem if, in the instalation site, we have no internet connection; for commisioning we will have temporaly internet connection, of course, but with week signal.

My design principle was starting from schematic below:


Thank you for your answer.

ovidiu asked
Eduard answered ·

2 Answers

PV meter on the output of inverter data


I have an ESS running with Cerbo GX, Multiplus II, and an AC coupled inverter on the output of the multi. Until recently i didn't monitor PV production but today i installed an EM111 meter, it's communicating fine however I cant configure it that its connected on the output of the multi. I select the position of the meter "AC Output" but its reverting back to "AC Input 1" once the page refreshes.

This causes "AC Loads" calculations to be incorrect.

I did set up in ESS assistant the PV inverter on the output and by the looks of it the generation is being counted twice.

Thanks in advance for assistance




apple047 asked
apple047 answered ·

1 Answer

AC Solar With DC Solar

Hope somebody can assist me I am new to using Victron however I am a qualified electrician, and I have recently bought a house with an existing installation, I have an grid fed Multiplus 48/5000 70-100 together with an SMA Sunnyboy providing Solar AC, I have recently upgraded my battery bank to a big Lithium ion pack but now the problem I am sitting with is that the solar array isn't sufficient enough to recharge the batteries during the day so I would like to add an Victron MPPT with a few extra panels. I have an Colour Gx in the system, now my question is do I just install the MPPT and connect it to the DC side of the Multiplus ? and connect the comms to the ? is there anything else I must do beforehand?

bart182 asked
Alexandra answered ·

1 Answer

Why is the Multiplus II frequency changing before the battery is full?

Good morning, I have a fronius connected to accept out 1 on victron multiplus II, I am checking how it runs without public grid, but I realize I have solar power, but the victron increases the frequency an the battery is not full. What could be the reason? Thanks in advance



palom170 asked
palom170 answered ·

2 Answers

Too much PV power input MPPT 100/30

I own a MPPT 100/30. The data sheet says if too much PV input power is installed, it will be automatically limited. Is that true? Under best conditions my setup would deliver 700 Watts. Question: Is there any damage possible or will the input power be limited to 440W (12V) ? All other parameter are in specification (~84V, 11A) Can I run this setup?

mr-simon asked
netrange answered ·

1 Answer

AC coupling BYD Battery-box Pro13.8, with microinverter and 4 inverter Quattro 48/5000/70


We have a PV system with 4 inverter Quattro 48/500/70 and 2 battery-box Pro 13.8.

Righ now we are only going to expand the photovoltaic system to 10.9kW, but the AC- coupling manual indicates ""Each additional 1.5 kWp of AC PV will require an additional proportional 4.8 kWh increase in battery storage""


10.9kW (AC PV) / 1.5 kWp x 4.8kWh = 34.88kWh

but, I have 27.6kWh (Battery)

Can I expand the System without more batteries?

or I have to add more?

rosimar-diaz asked
Vangelis Beligiannis answered ·

1 Answer

Sizing of PV power and PV inverter in AC coupling systems
Hello everyone, I'm working on the solar project and as my clIient is a bank I choose an AC coupling system.The problem is that with 1:1 rule, the energy of solar panels does not correspond to the energy demand.can I oversize the PV power of PV inverter?This will not creat a imbalance in the system    
as explained by the document attached?Thank you in advance

Deutch asked
Alexandra edited ·

0 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
Matthew Walsh answered ·

3 Answers

Compatibilidad inversos cargador multiplus

Buenas Tardes

Mi nombre es Diego Mac Lean, soy de Chile. Tengo un sistema on grid de 5kW inversor solis de 4 generación. Quiero instalar un sistema AC coupling con un inversor cargador y baterías respectivamente. Puede funcionar, si mi inversor viene configurado con la norma VDE-4105 para disminuir potencia por frecuencia, y lo otro éstos equipos se pueden comunicar como lo hace con el inversor Fronius o el inversor SMA.

Muchas gracias.

Si alguien ya ha hecho esta configuración que pueda asesorarme se lo agradecería.

saludos colegas.

diego-nicolas-mac-lean-guerra asked

0 Answers

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
jomugu commented ·

1 Answer

Does frequency shift regulation depend on the nominal inverter power?


if a Primo generates 3kW at 50Hz and the regulation goes to 51,9Hz, what's the new power rate?
Is it 50% of 3kW or is it 50% of the nominal inverter power?

Or asked differently: is the regulation of an inverter with less nominal power more accurate than with a bigger unit even if there is the same solar power installed?

As this is a little bit specific probably @Guy Stewart (Victron Community Manager) can answer?

Thank you!



porcini asked
porcini commented ·

1 Answer

Anyone uses SMA SB 1.5 / 2.0 / 2.5 AC-coupled OFFGRID ?


I'm wondering if the small SMA inverters supports the "OFF-Grid 50" country code. Unfortunately SMA support doesn't answer. I know SB 3.0 and above do, but the smaller ones are not listed. Does anyone know and uses one in an offgrid installation with multiplus/quattro/phoenix? How does it perform?

The "problem" with Fronius is that is has a relatively high nominal voltage and efficiency at lower workload/voltages is pretty bad. Although Fronius has a wider frequency bandwith I would prefer an SB 2.5 since my daily load is only between 250-1000W at most of the times.

Thank you very much!



porcini asked
Rob Duthie commented ·

2 Answers

Quattro/Multi Temperature Derating/Overheating behaviour in AC coupled mode

Just asking for some confirmation of what I believe I am seeing here,


This data is showing the quattro temp derating in AC coupled mode correct? The stepping of the AC output frequency and corresponding PV inverter yield coincides with the temperature warnings. The co-located MPPT yield is not throttled, the batteries are at ~65% (LA) and are in absorption, however the throttling is seeing the voltage not holding.

To me the device looks like its heat saturated, The PV Inverter reductions are too symmetrical and correspond with the temp warnings to be clouds.

It would be great if there was an indication the unit was derating or a internal temp sensor to verify.


So have a little more info from the site, the fans in the unit are slowly winding up then try to go to full speed and shutoff, this happens at exactly the same time the unit derates.

This leads me to believe that the power bus that runs the fans is exceeding its current and shutting down. Maybe by a self resetting fuse?

This unit runs a small island so sending the unit away will have problems.

It is possible for victron staff to look at any more internal data via the console to possibly determine the issue?

@mvader (Victron Energy) @Guy Stewart (Victron Community Manager) @Johannes Boonstra (Victron Energy Staff)

alan asked
alan edited ·

0 Answers

Interlocking AC-Out2 with AC-In possible?


I'm using general flag to ignore AC and some other assistants. I'm wondering if it is possible to switch AC-Out2 off BEFORE AC-In comes available and on again AFTER AC-In gets cut off.

I want to use a Fronius which isn't allowed to be connected to the grid

Thank you!

kind regards,


porcini asked

0 Answers

Can multiplus II optimize self consumption of PV AC generated energy in a 3-phase house

Schermafbeelding 2021-01-30 om 12.42.38.png

Wij zijn op zoek om onze zonnepanelen uit te breiden met een batterijsysteem van 20 kWh.
Onze solar installatie heeft 15000 Wp en zal ongeveer 12000 kWh / jaar produceren.
Ons verbruik ligt ongeveer bij 40 kWh per dag verdeeld 50% dagverbruik en 50% nachtverbruik.

We willen volgende functionaliteit :

1. backup en nood systeem in geval het net uitvalt voor een beperkte tijd (max 3à4 uur)
2. een optimalisatie van de eigenproductie voor zelfverbruik en, indien nodig, netvoeding te voorkomen

Kan de Victron Multiplus 48/5000/70-50 ons hierbij helpen en kan de victron in bijgevoegd schema ook aan zelfverbruik optimalisatie doen om het productieoverschot van onze zonneenergie overdag te consumeren s’avonds en s’nachts?

Wordt er rekening gehouden met battery-life voor de winterperiode waar we onvoldoende zelfproductie hebben om de batterij volledig te kunnen opladen? Wat doet de victron in dat geval?

frankvdn asked
bjorn-n commented ·

3 Answers

Fronius PV peak power Limited

We installed 2 Victron 24/3000 in parallel and a Fronius Primo 3.6 connected in the output of the multis.

First we configured with ESS and the fronius was working fine. It reached 3.6kW.


We had some problems with the grid and we had to quit using ESS. We had to configure the PV inverter support Assistant instead.

The AC side worked as we want, unfortunately, we realized that the PV production is limited to 2286kWp for some reason.




Fernando Kitsuta asked
Leslieanne commented ·

4 Answers

ESS not charging Excess power on AC out nor AC in


I have A System running in ESS mode paralleled to the Grid. The batteries are charged via Solar and three Multiplus II create a three-phase grid. The Grid on the AC IN ist just for the Power Assist, if the Multiplus can't supply enough power or the Batteries are empty. There is also a AC coupled PV on the AC in Side.

However on the AC Out there is a block-unit heating power plant to supply heating and power. Because of the Grid Code in Germany the block-unit heating power plant must be on this side. Now my Problem is if the genset is running and supplies to much power than needed I want the Multiplus to charge the Batteries instead of feeding it into the grid. I don't know how to do this an couldn't find any explanations about this constellation.

The System also does not use the excess power of the AC coupled PV.

It would be nice if anybody could help me with this problem. If it isn't possible maybe there are other solutions to have the grid as backup, charge the batteries with the genset an have a zero feed in to the grid.


Thanks in advance and i hope you can understand what I am trying to do, as a german trying to write down a technical problem in english.


pchilli asked
pchilli edited ·

0 Answers


Am planning to install a 10kva system ac and dc coupled system the system which was designed by the installer had PV passing through two mppt 150/100 to battery bank. Quattro inverter CCGX

My question comes the installer advised that one can add an additional fronius inverter to the system after the designed has already factored the 1:1 rule as long as it’s rated smaller than the overall inverter charger. Meaning that there are two fronius e.g 10kva and 5kva on a quattro 10kva bus

hussein-khamis asked
alan edited ·

1 Answer

Combine 2 3-phase quattro hybrid generators

I have a 30kW Hybrid unit including DC generator, 48V Li batteries, 3 x 10kVA Quattros in 3phase. The inverters are in inverter mode only and do not charge the batteries, the generator charges the batteries, controlled by a PLC. The inverter configured to cut off at low voltage setpoint.

I'd like to combine two of these units to serve a max of 60 kVA load , 3 phase.

Can I AC couple these systems ? Connecting inverter 1 of each unit to phase 1, etc. so I'd have 2 inverters on each phase, 20 kVA per phase?

Is this possible ? How would it be configured software ?

I realise normally two DC batteries can not be used if not on same DC bus, but does it matter if the inverter never charges the batteries ?

energylad asked
alan commented ·

2 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

3 phase ESS Ac coupled system


I have been asked to look at an existing renewable system. There is a 3 phase supply with various existing renewables (PV and Wind) feeding in to different phases via single phase Grid Tied Inverters. The customer has asked for more PV to be added to the system. This can easily be achieved by using an MPPT.

If I add 3 Multi's and configure them to a 3 phase ESS set up, will the system work and charge the batteries using the existing single phase GTI's AC coupled to separate phases? Would it be better to throw away the existing single phase GTI's and replace with 3 phase units and AC couple across all phases?

jamie-robinson asked

0 Answers

Offgrid PV Inverter Support Assistant and the fixed 13.5V / 27V / 54V limit

To prevent DC and AC voltage overshoots because of varying solar irradiance and/or load fluctuations, it will limit the charge current already before battery voltage has rised up to the absorption voltage. It will derate the maximum charge current from 100% at 13.5 / 27 / 54V to 10% at 14.4 / 28.8 / 57.6V. These thresholds are not related to the configured absorption voltage.

Hello, knowing this has already been increased a few years ago and is somehow necessary, I'm still wondering about the reasonableness of the fact the voltages are fixed.

In my opinion this should consider capacity:inverter ratio and especially battery type and voltages! Using a relatively small inverter in a big sized lead acid offgrid installation this makes the AC-coupled power pretty useless for charging, although lead acid doesn't care much about overvoltage!

Now let's look at the Pylontech or other 15s Lithium-Storages, that probably don't even have a GX. Their absorption voltage is below 54V so there is no derating at all, although Li can be damaged by overvoltage? Further this means 15s systems can use the full power for charging while 16s or lead acid systems are extremely disadvantaged. Due to the fact that this is for protection I don't understand why some systems can use the full power up to absorption voltage and others cannot.

Can someone tell me the technical background of the fact that the voltages and the derating are fixed and anything else isn't considered? Probably @Johannes Boonstra (Victron Energy Staff)

Thank you very much!



porcini asked
porcini edited ·

2 Answers

Shared PV negative with two Victron MPPT chargers

hi there,

I have two 150/85 victron charge controllers that I want to use to charge a single battery bank.

I have two solar arrays, each is sized for one charge controller.

I know the pv positive cables from each array need to be kept separate for each charge controller. Can the pv negative from my two arrays be on a combined cable?

I would run a larger negative cable if the negative cables can be combined.

I plan to use a midnite solar mnpv12 combiner box, and combining the negative feed for both arrays is the configuration shown in the manual with two charge controllers. The positive feeds are kept separate of course. I would have to cut the negative bus bar in the combiner in half to separate it per charge controller.

If possible, please state why- if you recommend against

I haven’t been able to find much information on best practices to run multiple victron charge controllers with the same battery bank-



chrisgru asked
wkirby answered ·

2 Answers


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