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AC PV Coupling

Microgrid AC loads in VRM/color controll

I have a microgrid solution with Quattro and fronius without grid
Also a Can-MPPT directly on battery thrue a BMV.
System works very well.

However it would be great to be able to see real AC loads in color controll and especially in VRM advanced to get a trend of it .
Now you have to add PV inverter power (fronius) and AC loads (Quattro) and subrtract battery charging power minus MPPT charge power.

txs Marcus

maka asked
Paul B answered ·

1 Answer

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
jacobjned commented ·

1 Answer

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
greendovefarms answered ·

2 Answers

Grid tie Ac coupled quattro 5kva and fronius 8.2.1 with color control


The fronius pv inverter does not generate power and stays on 0W.

It only generates if I switch it to slave but then I dont see it on the color control and I can not limit feedback to the grid.

I have an ac coupled system connected to the grid.

Quatttro 5kva with Fronius 8.2.1 connected to ac out and they are connected to the color control.

I have also installed a Carlo Carvassi et 112 meter and a bmv700 batt monitor and enabled it.

I have loaded ess and configured it and changed the fronius to mg50

The color control sees all devices and displays it correctly and shows fronius pv inverter.

I have set the color control to keep batt charged.I have disabled zero feed in and enabled feed excess power. Solar charger control voltage and current is off dvcc is off.

I have gone trough lots of document but did not find anything that solves my problem.

I would appreciate any suggestions.

Tnx @Guy Stewart

@Matthijs @Johannes Boonstra @Fronius Danmark

martinh asked
palom170 commented ·

2 Answers

Rule for Combining AC and DC coupling in off grid system

Hello @Guy Stewart (Victron Community Manager) and @Alexandra,

I would like to know how much DC coupling to apply in an AC off grid system for a well balanced system.

Does the amount of power to be installed on the DC side in an off-grid AC system depend on the capacity of the batteries? If so, what should be the power on the DC side, to avoid the batteries being flat? If there is a generator, is it necessary to add a DC coupling, or would it be interesting to start the generator automatically in case of low batteries?

Thank you

Deutch asked
Deutch commented ·

2 Answers

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
stephanie answered ·

1 Answer

ESS Fronius Ac-In, doubt about shore current limit


Hello victron community members, I have a doubt about AC in grid limit

Currently in Spain, with the electricity tariff change we can hire 2 powers, so we can configure the ac in limitation of the victron depending on the schedule, I have a fronius in ac in and yesterday I did a test, by limiting the ac in input of the victron at 6A, once it reached that consumption in loads in ac out 1 it no longer generated more, it started to take power from batteries, is it fine? Is it not able to detect that this energy comes from the inverter? and not from the públic grid.

Thanks in advance.

palom170 asked
palom170 commented ·

1 Answer

MyPV AC-Thor in off-grid system - settings?


the manual ( ) says that when using AC-Thor in an off-grid system frequency shifting (PV-inverter assistent) has to be activated at the Multi.

- Is this also necessary if only DC-coupled PV is used (no PV-inverter on AC-out)?

- what are the frequency settings in the "PV-inverter" assistent? Are the default-settings ok?

Best regards

e-box asked
Robert Bazalgette answered ·

4 Answers

Sharing my setup details for others to learn (JAG35 18650 + Victron gear)

Hi Folks,

A community is as good as the information shared by it's contributors so let me share my working setup for other to learns (and happy to further detail if not enough)

My setup consists of 2 banks of Jag35 (the famous youtuber) 10 times 7s 18650 cells with a Daily Li-ion 7s/24v Charge 30a / Discharge 60a BMS. (each bank has it's own BMS).

A Victron 100/30 MPPT smart solar charger (USB hooked to the Raspberry)

A Victron 24v battery protect

A Victron Raspberry PI (VRM Portal) monitor

A Victron SmartShunt (USB hooked to the Raspberry)

A Victron 24v-48v DC-DC juices a cheap Chinese Grid-TIE interverter

All wired accoording to the Victron Wired bible.

A set of 6 Solar 105w 4A panels in parallel. (Amp is King)

The weird thing about my setup, I'm hybrid.. I feed this to a cheap Chinese Grid-Tie inverter to my own home and as such consume all of it w/o returning it the bigger grid. (why doesn't Victron deliver a standalone grid-tie????) The BP protects the drain and returns to charge when needed.

This setup requires more tuning but it's working and it's a nice (home grown) hybrid kit.

Happy to share more details on the Lithium parameters but they are pretty standard.


(I'm LoRan nerd as well, hence the antennas)


robert-welling asked
klim8skeptic commented ·

2 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
kenyon commented ·

3 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
darek commented ·

3 Answers

Elegant AC- coupling high frequency lockout reset?

Firstly, I am aware of the 53hz lockout condition and how to reset it and the battery voltage conditions to reset automatically.

In the large 3ph off-grid system I'm considering I intend to have both DC and AC coupling.

On a light usage day, which will be the norm, the frequency will lock out the PV inverters and I am fine with that.

Scenario 1:

However, sometimes I want to run an 11kW 3ph irrigation pump when there is good sunshine and supposedly plenty power. Now, that pump has quite a start-up current, so I want all available inversion power at the ready to be able to handle that current surge.

The thing is those PV inverters will be locked out for the day already by then, the batteries will be charged.

I don't want to restart the system via PC and I don't have a 50Hz supply, being off-grid.

Scenario 2:

The PV strings will be very early and very late power production in the day, given the big battery size they will probably still be locked out in the morning. I'd rather be using this available PV power than forcing the battery to discharge in the morning.

Is there a possibility of a binary input to force this reset on demand?

Something that I can put on a nightly timer, or operate on demand when starting the pump.

Yes, I can force the other reset methods, but they seem very unwieldy, I am looking for a more elegant solution.

Phil Gavin asked
Phil Gavin edited ·

1 Answer

3 phase asymmetrical system?

I noted from another forum answer by @Johannes Boonstra (Victron Energy Staff), that 3 phase asymmetrical systems are an option.

Different numbers of multi's on each phase.

I understand the need for AC and DC cabling symmetry within those confines.

However, when I look at the ESS assistant and the PV assistant the first message that flashes up is that there must be a symmetry of multi and PV inverters.

In an off-grid set-up, if I want an asymmetrical system as far as Multi's go, do I have to forgo the option of AC coupling?

Phil Gavin asked
Phil Gavin commented ·

1 Answer

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

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


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