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fronius off-grid

Cumul des puissances Fronius + Multiplus en couplage AC


Je dimensionne une installation Hors-Réseau avec un Multiplus + couplage AC Fronius Primo + couplage DC.

J'ai bien compris la règle 1:1 en couplage AC.

Mais je cherche à savoir si sur une belle journée et avec les batteries chargées on peut cumuler ou dépasser la puissance du convertisseur + celle de l'onduleur. P_tot=P_Multiplus + P_Fronius

Le client souhaite alimenter une machine de 2000W uniquement lors des belles journée mais avec ces autres équipements il peut y avoir des consommation jusqu'à 4200W au total sur 2h cumulées.

Je pense coupler en AC un Multiplus 3kVA avec un Fronius Primo 3kVA et commencer avec 1.5kWc en couplage DC que je peux facilement faire évoluer.

Le but est de na pas passer sur 5kVA car le client ne consomme pas plus de 2000W 70% du temps

Merci de votre lectures et vos réponses

tdy74 asked
Thierry Cortassa (Victron Energy Staff) answered ·

2 Answers

Controlling a Dump load on AC2 Out using assistants depending on SOC AND charging level

Off Grid installation with 8.2 KW Fronius AC coupled on AC1 Out and 10000VA quattro

I have successfully set the relay assistant to switch on the AC2 Out relay when SOC is above 92% and off when SOC drops back to 91%

However when a cloud for example comes over and my PV drops significantly I want the AC2 relay to temporarily switch off again until it clears

I am thinking to use an additional relay assistant to switch AC2 off if batt voltage drops below 50.5 volts and on again when above 51 this i think would mean i only load AC2 when i am truly in surplus generation mode??

tas6 asked
mrhappy commented ·

3 Answers

Parallel Fronius Offgrid

Hello questions,

Current installation is an off grid Miltiplus II 48/5000 AC coupled to a Fronius Primo 4.0.1.

I will be upgrading to a 48/10000 soon, can I parallel two Primo 4.0.1 together with this configuration?


Dave Rae asked
marekp answered ·

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

Off grid 1 to 1 rule for PV ac coupled solar

Off grid installation

I have currently 8.7kw solar through a Fronius 8.2 primo ac coupled to AC1 out on a 10000va Quattro +
Us2000 Pylontech X 5 batteries. 28kw single phase generator and Color GX to monitor and control with a lynx dc
I have a further 8Kw of solar still to be fitted

Current settings

Fronius limited to 6kw output max (just to be safe - I hope to increase this to 8.2kw after input from this thread)

Generator configured to come on when SOC falls to 20% to protect batteries

Plan - questions

I am considering placing to 8 kw on the dc side with a Victron charger (could you recommend one)

Using the 1 to 1 rule am I right in saying i can safely go up to 10kw of ac coupled solar (possibly by adding a second smaller ac coupled Fronius) note that the actual charger on the Quattro states 140amp as the charging max.
if I put the other 8 Ish solar on the dc side will this have any effect on what I should limit the ac solar too?

I am thinking to add a further 3 pylon tech to the system to bring me up to the 8 max they allow without a separate controller but I read somewhere on Victron that I should have 4.8kw of storage for each 1.5kw of solar - this is an awful lot of storage !? Is there a reason for this ?

I intend to program the Fronius to reduce its output to 50% when the SOC is above 90% to protect the batteries and attempt to stop them going all the way to100%

I am having great results currently running completely off grid - tumble dryer, washing machine, dishwasher electric ovens etc - AND charging an Audi etron but I am trying to organise myself for winter

Thank you for your replies

tas6 asked
shaneyake commented ·

2 Answers

Quattro 10kva 3phase system - Swells and dips over 10%

*****System: Off Grid

3 x Victron Quattro 10kva

1 x Fronius 10kW Symo - 1 x 20kW Symo

18 x Pylontech US 3000

2 x Skylla 48v 50ah AC chargers ( Supplement charge for batteries )

84 x 410w JA Solar Mono half cell

System was installed on new build home. We experienced dipping in the lights. The electrician has done a logger test last week and the results are a bit concerning. Lowest dip recorded was 180v ( 10 - 60 milliseconds), and it regularly dips below 10%, 207v.

Highest swell recorded 257v (10 - 60 milliseconds )

Attached logger data and Victron data ( 1 min intervals )

AMSO 1216 JNF Electrical.pdfHuis Visser Statistics for week 21 May to 28 May 2021.pdf

L1 (Victron) - Phase B (Logger Test)

L2 - Phase C

L3 - Phase A

The underfloor heating runs on Phase C (L2). It switched off on Tuesday morning and technicians are coming in to have a look.

My question is, has anybody experienced a similar situation? Is there a way to minimize the shifting?

Thank you



* Results of second test. First 36hrs main DB incoming 3 phase line from Off grid system. Last 36hrs directly on Victron output and termination boxes. (This was done to check that data corresponds and we have no other electrical problem in-between DB and Inverters.)

AMSO 1217 Test 2.pdf

Results are still the same.

*The underfloor heating has been fixed. Unrelated issue

* We have done a firmware Quattro's and N-E bond in the termination boxes. ( This was done before new logger test was done)

* Lights are more stable. Flickering only happens when sun is going down, load increases and the shift happens between Fronius not being able to supply sufficient power and the batteries taking over (100% SOC) I will follow up with Fronius to see if there is a fix for this. ( I have upgraded the Fronius to latest software)

* My question is: The fluctuations are very short in duration 20 - 40 milliseconds. On average we remain on 230V. I do understand being fully of grid will make the voltages fluctuate. Is this in normal parameters? Is there a way to minimize it? Will it have a negative long-term effect on household appliances?


johanh asked
tozz commented ·

2 Answers

Fronius Error state 107 - Off grid with Fronius on Output

Hi All.

I have a Fronius Eco on the output of 3x 15kVA Quattro inverters.

PV Inverter assistant is loaded and the GX device picks up the Fronius inverter successfully.

The Fronius give error state 107 - The AC grid outside the allowed limits.

Please assist?




corne asked
greendovefarms edited ·

0 Answers

actually have Multiplus want to add Fronius prime

Hello Friends at Victron !

I actually have an off grid system that runs with a recent (2018 I think) Victron Multiplus charger/inverter 5000VA (24/5000/120), a battery bank 1500Ah 24V and a Victron Blue Solar charger 2000W fed with 3kWp PV array.

I have installer another 10 kWp PV array and I'm looking for obtaining the best from it.

Picture here under is the actual configuration , and the new part to add : it was imagined as the addition of a band new fromius primo 8.2kW to feed the microgrid. I've been told the actual fronius Primo and my actual Multiplus should work together perfectly.

My questions are :

-will the multiplus charge the battery using the ac provided to it on its output ?

-could the multiplus be unhappy of this configuration as the Primo is overpassing the 1-1 rule, means are the problems related here are they still relevant to 2018 multiplus and Primo use ? as they are supposed to be very well fit together by Victron & Fronius ??

-if breaking this rule would be a problem , if have a setting at the Primo inverter to let him produce AC standalone and then install the Primo at Multiplus AC in , instead ? supposed no more rule 1-1 problem then ?

-otherwise if I purchase a primo 8.2kVA, I may be obliged to set software limitations to example 5kVa maybe ? And then make trials with oscilloscope switch on/off loads and see how behave frequencies and voltage when shut off to confirm the settings in the particuliar setup ?

I used to be a solar installer, but no more commercial now, and the technology improvement require us to update. Not easy, many manufacturers. I decided to keep using the victron, nice manufacturing, but feels a bit sad to see the new blue solar charger full of gel, cannot be repaired anymore.

The Victron products can be used in so diverse situations, it's an enormous Job you are doing at Victron. Thanks a lot for your help !

I am wishing to bring an interesting question that may interest many. Haven't found related equivalent in history.

Also thanks to anyone that who agrees to help !


franck47 asked
Vangelis Beligiannis commented ·

3 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

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

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

Comment connecte le fronius sur le Color Gx

Bonsoir j'ai installe un systeme OFF GRID avec trois Quattro de 8kVA et un Fronius de 20 kVA et un Color Gx. Quand les batteries sont pleines le Fronius continue de les charger. Il n'y a pas internet dans la zone, comment on peut connecter le Fronius sur le Color Gx?

el-hadji-daouda-ndoye asked
Carrara Frederic answered ·

2 Answers

AC Coupling - Quattro frequency shifts despite large AC loads that could be supplied by Fronius


We commissioned an off-grid system yesterday consisting of Pylontech lithium batteries, a Quattro 8000 a 250/60 MPPT with 8 x 330watt panels and a Fronius Primo 3 with 12 x 330watt panels.

The Fronius is set to Micro Grid 50Hz and the Quattro has been configured as per the default settings to control it via frequency shift.

In order to check everything we ran a "stress test" on the system by turning on loads peaking at 7,000watts and averaging 5,000watts. At the start of the test the batteries were at 96% SoC and at the end of the test they had dropped to 89% - whilst this test was underway the 250/60 was providing around 2.000watts of energy but the Fronius was not working at all as the frequency provided by the Quattro was stuck at 53Hz - it could have been providing 2,500 watts or thereabouts which would have covered most of the loads without discharging the batteries.

This is the Frequency from the VRM for that period


Does anyone have a reason why this would be the case?

More details from the VRM


Thank you

PS. This morning the Fronius is working and providing power to recharge the batteries.

mltbuderim asked
Guy Stewart (Victron Community Manager) commented ·

2 Answers


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