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Multiplus frequency shifting: stuck at control range maximum


I use frequency shifting by a MultiPlus 48/3000/35-50 (firmware v430, off grid) to control electrical heaters via an AC Thor controller. The idea is to maximize PV power consumption. Layout:


My MultiPlus setup is the following (full settings attached):

Charger settings:

Absorption voltage 55.50 V (absorption voltage of set MPPT = 57.4 V)
Float voltage 55.10 V (MPPT float 55.2 V)

PV inverter support assistant settings:

*) The solar converter will start reducing its output power at 50.10 Hz.
Output power will be reduced to minimum when the frequency is 51.00 Hz.
The converter will disconnect when the frequency is higher than 53.00 Hz.
*) Total installed PV inverter power is 1500 Watts.
Total installed PV panel power is 1500 Watts.

The issue is that the MultiPlus frequently gets stuck at the maximal value of the frequency control range, i.e. 51 Hz. So not at the "disconnect" value of 53 Hz, which seems to be reset according to what is written in the documentation of the PV inverter assistant (at a voltage equal to Float V - 5.2 V).

An example of this issue is shown in the graph below. At time = 0 h (midnight), the system is already stuck at 51 Hz from the previous day (green curve), despite the fact that the battery voltage is 49 V or lower (blue curve), which is well below the charger absorption voltage setting of 55.5 V (dotted blue line). I had switched off the AC Thor loads the previous day, to avoid battery draining.

In the morning I remotely reset the MultiPlus to get the frequency back at 50 Hz.

At around 12:00 pm, the system did what it should: when the battery voltage increased above +/- 55.5 V (blue curve), the frequency shifted. I switched on the loads again, and AC power was sent to the heaters by the AC Thor controller (red curve). I have two sequential heaters of different power controlled by the AC Thor, explaining the variation in AC power consumption.

One can also see that at the end of the day, around t =18 h , the system again was stuck at 51 Hz (and so power consumption maximal at 1500 W), despite the fact that there was not enough PV power available and that the battery voltage reached values as low as 48 V. This is far below the absorption (and float) voltage set for the MultiPlus charger, so one would expect the frequency to be shifted back to 50 Hz. The battery was drained to 80 %, at which time the AC loads were switched off automatically by a Multiplus relay that I programmed for this purpose.

The problem is of course this behaviour drains the battery unnecessarily.

Weirdly enough, the issue does not always happen. Many times it just works as it should (see bottom graph). I did not find any regularity, except that it seems to happen on days with alternating sunshine/clouds, and after the Multiplus returned from the "disconnect" frequency, 53 Hz in my case. Similar behaviour has been reported a few times before on this forum (mostly in the context of frequency shifting for AC coupled PV charging) but a definitive solution was not given.

Can this be solved by changing the settings somehow? I tried many charger voltage/ frequency range settings already, but always the issue pops up. Or is this inherent to the way the frequency shifting is programmed?

Thank you.


Multiplus settings: MP_settings.txt

A good (sunny) day - example of how it should work:


alexander-aerts asked
Paul B edited ·

1 Answer

Volts and hertz with Victron + pylontech

Hello. I'm new to the forum and I would like someone to help me with a question.

I have a Victron Quattro + Pylontech US2000C batteries. These batteries have a maximum charge voltage of 53.5 volts.

On the other hand, Victron says that the voltage at which the frequency starts to rise, in order to control an AC-coupled fronius inverter, is 54 volts.

The question is how can that system work, with these different tensions? it is impossible!!

Is there any way to modify the voltage at which the frequency rises, to adapt to the charging voltage of the pylontech batteries?


carlos007 asked
nickdb commented ·

3 Answers

PV inverter support assistant and DVCC


I have been succesfully using the PV inverter support assistant of a Multiplus 2 to control an external heater (excess solar energy dump in off grid system) via frequency shifting. My system had lead acid batteries.

Now I changed to Pylontech batteries. Charge control is now done via DVCC.

This caused the PV inverter assistant to stop working. I can configure the assistant, and as long as I don’t plug in the VE.bus cable of the inverter in the Cerbo unit, it works: ac output frequency is increased by Multiplus, as expected.

However, as soon as I plug in the cable, and thus establish communication with the inverter, the DVCC seems to overrule the inverter and PV inverter assistant stops frequency shifting.

Is there a way to make this work?



alexander-aerts asked
alexander-aerts edited ·

0 Answers

Off-grid PV Inverter support on AC IN - respond to frequency changes

In all of my searching, I can only find configuration options to modify the behavior of Multis/Quattros by changing the frequency on the AC Output. But I'm still a novice in the Victron world, so maybe I've overlooked something?

What I'd like to achieve is change battery charge/discharge parameters based on the frequency of AC Input. As far as I can see, this isn't possible, but I'd appreciate being corrected if I'm mistaken!

My goal is to use Multi to:

  • keep SoC > XX% (or keep a minimum DC Voltage)
  • if frequency > XX, charge batteries (ideally, current increases with frequency)
  • if frequency < XX, discharge batteries (via PowerAssist or Ignore AC?)

The purpose of this is to interact with an existing off-grid system in a supportive way. Grid-tied inverters will curtail their output in response to rising frequency. To avoid "wasting" that energy, I'd like my Multis to store power in the battery, until the excess condition is gone, then give this energy back again until the batteries approach empty.

I'd prefer to use an Assistant or Virtual Switch over something like Node Red, but I don't see the functionality there. Am I missing something?

randyoo asked
randyoo edited ·

0 Answers

MultiPlus I frequency shift for MyPV AcThor

Hello from Canary Islands,

I have already asked this question in another thread, but I think I'd better start a new question.

My config:

Victron MultiPlus 48/5000/70-100, Product ID 2624, Firmware v498, off grid

Victron SmartSolar Charger MPPT 250/100, Product ID A050, Firmware v1.61

Lithium battery YUASA 2x15 cells, 120 AH


Victron Venus GX

MyPV AcThor 3 kW single phase wiht a heating cartridge 2500 W, frequency control.

This is the MultiPlus frequency control setting:


But it didn't work the way I hoped.

I want the frequency to increase in case of PV surplus. This would be the moment when the Solar Charger decreases the charging power.

But the frequency only increases when the maximum battery voltage is reached (my BMS is set to 60.02 volts). However, the control behaviour is such that the battery voltage drops to 59.79 volts in float and remains there. That's why the MultiPlus regulates the frequency down again immediately. So I only have a few minutes in which the AcThor could work. How can I ensure that the frequency remains at 51 Hz as long as I have a surplus?


Thanks for your support!


@Lucian Popescu (Victron Energy Staff)

nilsk asked
nilsk answered ·

4 Answers

Does Victron Make a 240V Single Phase VFD

I am trying to prevent inrush current for inverted 240v single phase loads on a boat. Does Victron make a VFD for 240V single phase VFD that will suit this application?

Abram asked

0 Answers

Quattro Different Frequency Inputs

I am planning to use 50Hz generator and 60Hz shore AC for my Quattro AC inputs.

Specifications already indicated that AC Input frequency range is 45...65Hz and existing questions in community said that transfer switch must be configured o accept wide range (45...65Hz) in VE.Connect.

I wonder is there anyone practically using Quattro AC inputs in different frequencies? Is there any trips or faults? Or it is recommended practically?

Thanks in advance.

Melih Manisalıgil asked
billknny answered ·

2 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
Warwick Bruce Chapman commented ·

7 Answers

Virtual Switch Settings Help Needed please

Good day All

My setup as follows:

Victron Multiplus 48|5000|70

MPPT 150|35

SunnyBoy1.5 ( On AC Out L1 of Multi )

Newly installed:

Venus GX

2x 48V 100Ah enerSol LiFeP04 With CANBUS BMS

I used to have LA batteries and used the following assistants:

General Flag for AC Ignore

Generator assistant

Self consumption Hub V2 / 3

The setup ONLY went to grid when batteries were "flat" so to speak.

All worked well until now....

After installing the new batteries and VGX I had to change things up a bit.

Because the Self Consumption V2 / 3 Assistant DOES NOT have an option for CANBUS

LiFeP04 batteries I can no longer use it.

The Problem:..............................

How do I set my inverter to frequency shift to control the SunnyBoy's output if my battries are full? I can't connect it to the grid side of the inverter as we have a prepaid meter which deducts kWh if I feed into the grid.....

I found this section under VS options The part with the rectangle around it, I thought this might be for frequency shifting but am not sure as I can't find much documentation on the VS option.


Any advice welcome.



Charles Gibbs asked
Mike Dorsett answered ·

1 Answer

SMA Frequency Shifting with feed-in energy limitation

I have a SMA Sunny Boy 1.5 with Mulitplus 1600 working perfectly, frequency shifting works like a charm. I was wondering if it is possible to change SB 1.5 to SB 5.0 (way to big) but with setting up the "Maximum active power output " limitation of the SB 5.0 inverter to 1500 W to keep the 1:1 rule.

To have this working the questions is:

Does SMA's frequency shifting take into consideration the "Maximum active power output " ?

Why ? Because I just have a free SMA SB 5.0 which has two inputs (SB 1.5 has just one), I'd like to make it work again. I can't find this info anywhere, thanks for any info.


Philip asked
Mike Dorsett answered ·

1 Answer

Victron Multiplus 3000 + Solar Edge Single Phase Inverter Error: F-L1 Max


Config Docs:

Victron Inverter: Multiplus 3000

Solar Edge Inverter: Single Phase HD Wave 2.2KW

Solar Edge Inverter Error 'F-L1 Max'

Hello all.

I am hoping to get to the bottom of a high frequency error which is triggering my Solar Edge inverter to disconnect. My Solar edge inverter has been configured in APS mode (AC-Coupling) using the above documentation.

When producing power my Victron inverter is charging successfully in "absorption" before my Solar Edge inverter disconnects. From viewing my Solar Edge SetApp "status" page app i can see the error and a frequency level of 53hz.

I believe the frequency bandwidth config for my SolarEdge inverter and VE.Bus Config is the reason for this disconnect.

When contacting the Solar Edge support they said:

The error shown on the inverter display indicates a Voltage Value too high from the AC.
When the PV is generating more energy than the consumption, it starts exporting energy to the grid. What happens is that if the grid cable is not big enough, this energy flowing to the grid let the AC Voltage raise.

There is also the below note on the above docs which i am no sure is still relevant. My Solar Edge inverter firmware is 4.16.19

Note: In addition to the settings above it is important to contact SolarEdge Support to change a parameter in the backend to allow the frequency shifting with APS mode.

Can anyone help me figure out a solution to this issue?

Any help is greatly appreciated.


tokiored asked
tokiored answered ·

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
xury answered ·

3 Answers

temperature LED flashing with frequency shift

Hi all
I have searched for an answer to this with no luck.
Been working on the off grid setup today and have been having some issues, since my battery got to absorption/float stage and made the AC Fronius go into frequency shift, every time something large was turned on the inverter went out of using frequency shift, but as soon as it was turned off the temp LED would flash several times and throw up a warning in connect until it stabilised and went back into frequency shift mode, it's not getting hot at all as far as I can make out and the fan isn't running, it just seams to be a bit of a random thing.
Has anyone come across this, and any ideas why ?
Setup is 48v 930ah traction battery
Victron 48/8000/110
Fronius 8.2-1
Smartshunt 500
Cerbo GX
Thanks for any help

scraggs asked
scraggs edited ·

0 Answers

Frequency dip in the power grid -> ESS switches off

I am asking for support with a problem that I cannot solve on my own.

Two ESS systems are installed on two separate power connections:

System 1: 6x Multiplus 48/5000 3ph with 1280Ah OPZS, AC coupled PV inverter, the ground floor of the house is connected to the AC-OUT.

System 2: 3x Multiplus 48/5000 3ph with Victron-LiFePo4 400Ah, 3x MPPT 150/75, the upper floor of the house is connected to the AC-OUT.

Yesterday there was a drop in the power supply three times; the mains frequency went down to approx. 40Hz. The following happened:

- System 1 switched to "island

- Installation 2 switched off the AC-OUT power and restarted (three times).

My questions: Why did system 2 switch off? What settings are wrong with this installation?

In the screenshot you can see system 2.


Thank you very much for your support.


drmi asked
Paul B edited ·

1 Answer

Victron coupled to Solaredge WR - Shutodown caused by frequency coupling


I have 6 Multiplus II 3000 connected to a Solaredge SE17K with frequency coupling.

Today we had several power grid outages and Victron went to Standalone Mode. After some minutes the Solaredge WR shut down and stopped producing.

One hour later (grid was back online since more than 40 minutes) the Solaredge went back online also. In the error log I found:

- AC-Frequenz zu hoch (Linie 1)

- AC-Frequenz zu hoch (Linie 2)

- AC-Frequenz zu hoch (Linie 3)

So it seems that there is an issue with frequency coupling. I am using the proposed setup from the victron handbook:

  1. The solar converter will start reducing its output power at 50.2Hz
  2. Output power will be reduced to a minimum when the frequency is 51.2Hz
  3. The converter will disconnect when the frequency is higher than 51.5Hz

Is this maybe not the best possible setup ?

Can I make this setup more failure resistent with other figures ?

Any suggestions ?



gawan asked
dirk-s edited ·

4 Answers

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