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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 ·

5 Answers

Frequency shift- Quattro 48/15000

Good day .

Is there a way to determine why the inverter is Frequency Shifting ?

Is it possible to find out were the command comes from ?

I am running 3 x 48/15000 Qauttro , 56KWh Solar MD batteries and Solar Edge 27.5 Grid tie inverter.

The Qauttro's seems to shift the frequency and the solar edge starts throttling. Is there any way to determine what will make the Qauttro's start frequency shift ?


Johannes Cronje

johannes-cronje asked
Alexandra commented ·

2 Answers

Need some help defining "Frequencies" in ESS for SolarEdge PV inverter

I could use some help defining the disconnect frequencies in ESS for my PV inverter shown here; any help is appreciated!:


I live in the US, my inverter is 60Hz first off, these are default values I have not modified yet. My Inverter is a SolarEdge HD10000-H US. Active Power control via frequency is defined here in the manual, and can be set by the user:


It would seem that "P0 in my inverter relates to "The solar converter will start reducing its output power at XX Hz", I am guessing that P1 would be the next setting "Output power will be reduced to minimum when frequency is at XX Hz".. I am not sure what to enter for the final disconnect value though. The full manual on Power Control can be found here,

Can anyone provide any recommendation as to how I should configure this in ESS and which values should be selected for P0 and P1 in my inverter?

ee21 asked
Alexandra edited ·

2 Answers

Configure Multiplus 2 Frequency Shift with Sunny Boy 5KW (sma)

Hello everybody.

I installed actually one multiplus 2 5000 48v 70a with lifepo4 batteries (18s) and BMS JK.

I have one Sunny Boy 5kw installed in ACOUT with the multiplus 2. All the loads the multiplus 2 are in AC-OUT.

I have a question about the configuration frequency shift for the correct working multiplus 2 with Sunny boy.

The screen for configure Sunny boy frequency shift (default) is this:


What configuration I have to configure to multiplus 2 ESS?? This??


Thanks in advance.

Best Regards.

alfredogutierrez asked

0 Answers

Flicker and wild voltage and frequency variation of Quattro output when operating with generator


We are experiencing this same issue on multiple sites. Both with AC connected PV and sites with charge controllers.

Quattro 5kw off grid system. 50hz 230v

When the backup generator is operating, the output from the Quattro varies wildly and also it appears so does the load placed on the generator - to charge the batteries (from the VRM portal data)

This is backed up up by the display on the generator (Hyundai DHY6000) which shows frequency.

Frequency output from the quattro is so unstable it cases the Fronius PV inverter to cut out and also the washine machine on site to go into fault. Also voltage is all over the place, and all this causes lighting flicker too.

UPS function setting is off

I have tried lowering the shore power setting.

I have tried lowering the output voltage slightly on the Quattro. (output on the genny when unloaded is 230v)

Dynamic current limiter on or off makes no difference.

Accept wide frequency range is on.

I am assuming that the quattros inverter attempts to track the AC input frequency and doesnt do a great job of it.

If powerassist was disabled - would this prevent the inverter output from trying to track whats happening with the AC input ?

Any ideas?



Chris asked
Chris edited ·

3 Answers

AC Coupled Fronius Drops Power on Shifted Frequency Prematurely and More than Needed

Hi, I have an AC-coupled Fronius Symos on 3-phase configured Quattro inverters. I have enabled Frequency shifting in ESS assistant with pre-set configuration: starts at 51, lowest at 52.7, shuts down on 53Hz. I have set the Fronius on MG50 to enable this power reduction on shifted frequency. But lately I noticed that at 80% SOC, the frequency starts shifting up, and the batteries cannot be charged properly on AC PV power, although enough power to charge them fully is available. I also know that Fronius on MG50 starts power decrease at 51Hz and shuts down on 52Hz. What can I do to have better charging for my batteries on AC PV (start frequency shifting on 90% SOC and end with 53Hz on 100% SOC)?

Nazareth Kevorkian asked
Nazareth Kevorkian commented ·

2 Answers

Still struggling to get AC-IN to connect.

Newly installed MultiPlus-II 5000 has been running great for several weeks now except for one nagging problem. I use Node-Red in ESS mode 1 to turn the inverter to Invert Mode at night time, then allow the batteries to charge in the morning. When the batteries are fully charged I switch the inverter back to ON mode to allow feed-in. Sometimes the AC-IN will connect within a matter of seconds, sometimes it takes hours. AC-IN is connected to stable grid-power at 50.4-50.6 Hz. Even at a stable 50.4 HZ for a sustained period of time it will not connect. Without changing anything, if the grid frequency drops to 50.1Hz or 50.2Hz for a minute, it will connect. Otherwise I have waited for up to 8 hours before it will connect.

Accept wide frequency range is enabled. I have tried all of the various other settings: weak AC, UPS Function, Conditional A/C Input Connection is disabled, etc.

I had mentioned this in a previous post, but it was a smaller issue that what I was facing at the time. So I decided to make it it's own post. Thanks.





cobraphil asked
cobraphil commented ·

1 Answer

Multiplus 12\3000\120 output frequency 45hz

Just installed a multiplus 12v 3000w to 120AC inverter charger on a boat. I'm using the mk3-USB interface to adjust settings. The inverter output frequency is set to 60hz, but its showing only 45hz on the output. This happens when running off 12v 500ah house battery bank. Please help!



louise asked
cyberhom edited ·

2 Answers

50Hz washing machine not running on Multiplus in Inverter mode

I have 24v DC system onboard with a Victron Energy BMS 400, 2x Li-ion HE 24/180A batteries and Multiplus 24/3000/70-50 charger/inverter.

I have a SOBA 1150 washing machine onboard (230V, 50Hz). On generator it works well, but if I start it with genset turned off and instead letting the Multiplus inverter mode deal with it – it simply does not work. Machine comes on as normal, start the program, it takes a few seconds before starting and I hear a pump running abnormally (same situation if I try running it on shore power with 230V/60Hz).

I see from other similar questions that there basically does not seem to be any good explanations, which is disappointing. I mean 3000W should be plenty (and I have everything else turned off), so I would not expect this to improve by getting an additional Multiplus.

Any thoughts?

ajaunsen asked
cyberhom answered ·

9 Answers

SmartSolar Charge Controller MPPT 150/35 Switching Frequency(s) for selecting RFI Ferrite Choke(s)

Looking to reduce the RFI from a SmartSolar MPPT 150/35. Can any one advise the switching frequency(s) generated by the device? (Amateur Radio RFI concerns - HF 1.8Mhz - 30MHz, 54MHz, etc)

Many thanks -

obelisk asked
jjbond answered ·

1 Answer

Frequency Shift staying high all Night

Hi, I have an installation with an 8kw Quattro and a 3kw Fronius AC coupled. 30kw of BYD Premium LVL. Also has 5kw solar on MPPT.

The Quattro shifts the frequency as expected when the battery is full, but doesn't drop it back to 50htz when the sun goes down. In some cases it drops it back at 2 or 3 am, and in the case of the attached PDF, it held it up until 6.50am the next day. Note the battery is down to 83%SOC. Freq graphs.pdf

Lawrence asked
jonatanjensen commented ·

1 Answer

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

inverter output frequency

I'm using US power (230v @60hz) and I plan to install a quattro 230v 5k with my 24v battery. Question is, even if I'm supplying 60hz to the inverter/charger from shore, can I program/set the inverter to outupt 50hz to my boat? (it's French built but now here in the US). Thanks for your help.

miami337 asked
ortessa edited ·

4 Answers

AC LOADS readings jumping up and down like CRAZY on Fronius AC coupled when frequency above 50.2V

My system is off-grid and has a Quattro 48/8000 with a FRONIUS PRIMO 3.0 on AC out, an MPPT 150/70 and a CCGX .

When battery is in float (55V) and the Fronius (on AC OUT) is regulated be the frequency (above 50.2Hz) the AC loads readings on the CCGX go crazy! Up and down by hundreds and even thousand Watts.

As soon as the frequency drops to 50 all is back to normal.

Any ideas?

Vangelis Beligiannis asked
Vangelis Beligiannis commented ·

2 Answers

Frequency shift without ESS


I am currently testing having PV inverter on the AC-out side of my MP-II.

The ESS is not yet implemented because I do not know yet if ESS will work without Power Meter.

The worry I have is, what will happen when grid fails, my battery is full and PV is producing allot of energy that has nowhere to go.

Will there be frequency shift sent to the PV inverter to turn it down, or it is only done when the ESS assistant is loaded?



marekp asked
marekp edited ·

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

Can a WEG Frequency drive create disturbing harmonics for a 3-Fase Quattro configuration?

For an 3 fase offgrid system with 3 Quattros - will be feeding 2 motors that are controlled by two WEG frequency drives (CFW500)

Is there any risk of that the frequency drives create a bad harmonic that can effect the Quattro inverter.

If yes, how can this be avoided?

Thank you in advance for your thoughts/solutions.

aboers asked

0 Answers

AC connect 3kW wind turbine Victron Quattro System

I have a Off-Grid Quattro 10kVA with AC Connected 3kW Fronius Primo solar inverter and 4kW of solar panels. Frequency shift is used to manage battery overcharge. System works great in summer but we are expanding for winter with additional solar, and a wind turbine. We will AC connect an additional 4kW Fronius and solar array. For wind, we are installing a 3kW 60V AC turbine that will rectify to 48V DC and this feeds to a grid tie wind controller/ inverter (China Supply) that will synch to the AC Bus. The controller will dump power to dump resistors to protect the turbine from over speed/ voltage/ frequency.

However, i am concerned the Wind controller inverter will not spill turbine power (trigger dump resistors) when the AC Bus frequency is shifted by the Victron Quattro (High batrery voltage). Logic tells my the inverter would disconnect on high AC Bus frequency and send all power to dump resistors, though I cant be sure and manufacturer info is sketchy.

My question is whether it would be possible as a back-up to use one of the quattros Programmable relays to trigger when the AC Bus frequency is shifted to say 53hz. In this way I could trigger dump resistors to spill wind turbine power when it is not needed for House Load or battery charging.

gallows asked
mvader (Victron Energy) answered ·

1 Answer

Frequency shift affecting AC unit

I Have a Quattro 10KVA DC coupled with a 250/100 and AC coupled with a Fronius 8.2kw with 6 x power plus 4KWH Eco batteries, the problem I am having is the house has a ducted panasonic AC system and works fine until the batteries reach 100% and the frequency shifts upwards and drops out the AC unit on high frequency. Is it possible either turn off the frequency shift and use AC out 2 to drop out the Fronius inverter on say 95% or battery voltage or ajust the frequency shift settings so it doesn't go so high.

iain-parke asked

0 Answers

Inverter voltage and frequency response on power failure

I have two separate systems where I experience the same problem. Both with Quattro inverters and with a grid-tied solar on the output side of the Victron inverters. In one system it is a Sunnyboy solar inverter and on the other, it is a Fronius. When the grid fails and the system goes into invert mode the solar inverter shuts down momentarily. I think this is because the municipal voltage varies quite a bit and when the grid fails the inverters instantly switch to an output voltage of 230V instead of the 240V that was supplied by the municipality, which will then cause the phase-locked loop in the solar inverter to lose synchronization and shut down. The municipal supply voltage can vary quite a bit, unfortunately, and as such the situation of a difference between the supply voltage and the Victron's voltage cannot be completely eliminated.

My question is this: What is the voltage and frequency output response of the inverters during a grid failure? Does it shift to the set voltage gradually over the course of several seconds or is it instantaneous?

Also, any thoughts on solving the problem of the solar inverter switching off would be greatly appreciated.

nelisvolschenk asked
michelg answered ·

1 Answer

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

What are the Parameters for frequency shift to Occur

Hi there does any know ????

I am wanting to know when does the freq shift up to say 52 hz occur

is it when the charge rate equals the Absorption voltage ie 54 volts plus 60 seconds (or what is the time period factor)

or is it when the voltage goes higher than the set absorption voltage of say 53.7, which is what I am thinking would be the case, so at say

53.8 freq is +.2

53.9 freq is +.4

54 freq is +.6

54.1 freq is +.8

etc etc

This is presuming that the Grid is disconnected and that the Grid tie inverters are outputting more than the consumption of the AC loads

Paul B asked
Paul B edited ·

0 Answers

One Multiplus II-GX 48/5000/70-50 with Fronius 4.0 on a 3-phase grid connected system.

Hello, I plan to use a Multiplus II-GX 48/5000/70-50 with Fronius 4.0 on a 3-phase grid connected system. The 2 phases are connected directly to the consumer and the phase-3 will pass-through the Victron-Fronius system supporting Energy Storage System on one phase only . I have the next 3 questions:

1, Does the above system works fine?

2. Is the Multiplus II-GX anti-islanding certified and does exist a certificate for Greece?

3. Assuming the 3 grid phases are on. Does exist the possibility on the above system to have on the 2-direct phases 50Hz grid freq. and on the phase-3 higher ( for example 52 Hz) due to MG shifting on frequency? (This frequency unbalance would be abnormal for 3-phase loads).

Best regards,


pkorkas asked
faizan answered ·

1 Answer

Multiplus Quattro AC frequency Hz variations

I've been trying to get to the bottom of why we have some flickering LED downlights in our house, especially those on dimmer switches. Dimmer switches are notoriousely sensitive to frequency variations.

I've been looking at my Multi's AC Output metrics from the VRM and I noticed that the frequency can sometimes drop as low at 48.34 Hz.

According the Multi's specs, there should be about a 1% variation on the 50 Hz output, which I calculate should only go down to around 49.50 Hz.

Can anyone tell me if this frequency variation that I am having is unusual for a Multi, or is that normal? I am wondering if this points to some type of fault?

This issue is occurring when we are running off the grid on ESS settings.

See screenshot below:


Nicholas Wessels asked
maremotomoto answered ·

6 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

Alternative to frequency shifting for adjusting AC PV power?

Hello, questions- is their a victron version of Selectronics managed AC coupling instead of the current frequency shifting as this is more precise and would eliminate any clock timer issues as well..

If not something for the Victron team to look at implementing perhaps?


Dave Rae asked
Guy Stewart (Victron Community Manager) commented ·

1 Answer

Unexpected AC frequency changes when set to 60Hz

I am running the Microgen Stirling Engine in an off-grid setup with a MultiPlus 3kW.

The Stirling Engine is a 60Hz-type so I have set the AC out frequency to 60Hz (@230Vrms).

This Stirling Engine has a frequency-operating-range of 60.0 +/- 0.5Hz. Our software has built-in protection: it stops the Stirling Engine when the grid-frequency goes outside these limits for more than 1 second.

We have quite a number of commercial setups with Victron MulitPlus's out there, all set up to 50Hz, all working fine.

But, when set up to 60Hz, a customer and I too, see unexpected frequency-jumps when the Stirling Engine is running. When this happens, the Stirling Engine stops and there is an error reported by the software. I have seen this error also appear in a system in my lab when the Stirling Engine is not running. There is nothing going on in these systems that would warrant frequency-jumps: there are no large loads being switched that could cause a frequency-jump.

Could there be a bug in the inverter software that only shows when set to 60Hz?

bouwew asked

0 Answers

AC coupled system Frequency lock

We have a Multiplus ll inverter/charger coupled to a Solis PV inverter. When the batteries are full the frequency rises until the Solis switches off. It then takes a long time to reduce the frequency again. The issue here is that we also have a MY PV Thor immersion controller, that dumps to the immersion based on frequency. When the PV inverter is OFF, because the frequency is still high, the THor draws power from the Multiplus and overloads it. How do I get the Multiplus to reduce the frequency sooner ? The instructions tell me that the battery voltage needs to reduce to 5.2 volts below the float setting ! In this case the float is 54 volts so 48.8 by which time the DC solar charging will be active keeping the battery volts higher.


Robert Bazalgette asked
Robert Bazalgette edited ·

0 Answers

AC coupled inverters that work with frequency shift (Solis?)

Hi Im after a list of brands that work with frequency shift to reduce output. Ive used fronius before that works well and ive heard SMA will aslo work, im wondering what other brands people have had success using, in particular im trying to find out if anyone has managed to use a Solis inverter as cost wise this would be great. Thanks

jacko asked
wkirby commented ·

6 Answers

Multiplus II having different frequencies in ACin and Acout1

I have the following setup:

1xMultipluss II 48/5000

1x 5kW grid tied PV inverter connected to the ACout 1 of the Multipluss II

1x BYD B-BOX 10 battery

Grid is conneted to the ACin of the Multipluss II and the grid tied PV inverter and loads are connected to the ACout 1. The Multiplus II is configured as an ESS system.

My problem is as follows: If I physically disconnect the grid from the ACin, the system works perfect. If I connect the grid to the ACin, what happens is that frequency in the ACout1 starts to change and the grid tied inverter stops inverting since frequency is out of range. This happens at any SOC of the battery and even at night when the PV invertir is not working. As long as I understand, ACin frequency and ACout1 frequency shoud be always the same, but this is not the case. Frequency variations goes from 48 Hz to 53 Hz (big changes in short time). I can also see the LEDs flikering sometimes. The main problem is that the PV inverter stops inverting due to changes in frequency. Does anyone have any idea why this is happening and how could I solve this problem. Thank you in advanced.

julian-monedero asked
Daniël Boekel (Victron Energy Staff) commented ·

5 Answers

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