I am having issues with Multiplus II 48/3000 and frequency shifting.
Pylontech batteries, all settings per Victron’s advice on settings.
PV inverter attached & configured in ESS assistant. Stop 52.3Hz
Simulated grid failure. When Pylontechs start approaching 100% the DC MPPT’s ramp down. The PV inverter -frequency shift hardly moves & the Pylontech batteries voltage increases over Victron’s recommended settings of 52.4v and continues to increase above 53.3v, frequency shift is slowly increasing. Eventually I manually switch off the PVinverter.
This has been looked into by the supplier and they contacted Victron, VRM authorisation access was given. The issue was reported in July 2025. Obviously concerned in the event of grid failure the Pylons may over voltage and cause issues.
The frequency shift works in the first instance of grid failure then decreases to allow the PVinverter to work eg batteries are at 80%
On grid failure, where does the Multiplus get its settings and Voltage readings from to control the frequency shift ? And can these be changed ?
1/ is it the BMS
2/ Multiplus itself
3/ GX readings & Dvc
4/ Nobody knows.
The supplier kindly wants to issue a refund for the multiplus, there is the issue this will make other equipment redundant and costs. Hence asking here for advice & hopefully someone at Victron will notice and advise.
The pylontec batteries actually request the higher voltage. Check under parameters in the battery settings. This will be part of the issue.
You can cap the voltage to 52.4v under dvcc set the max voltage there.
The voltage trigger, no. But the frequency shift values can be changed in the assistant programmed.
A quick fix for now would be to install it on ac2 out and have it switch off that way.
I do not understand why when grid is disconnected the DC MPPT’s stay within Victron’s cap of 52.4v recommendation/control, but not for the PV inverter frequency shift. The Pylontech batteries are showing 100% but their voltage is increasing above 53.3v (CVL53.2v Pylontech Battery Parameters). Is the trigger for the frequency shift different ? I will set the dvcc ‘limit managed battery charge voltage’ to 52.4v and test.
I was not aware ACOUT2 was bidirectional to allow a PV inverter to be connected.
I’m not familiar with frequency shift but things to clarify:
What you describe doesn’t appear to be normal behavior. I assume that you have done all the basics including upgrading firmware and updating all assistants?
Has Victron actually looked at your system? If yes, what was their conclusion? If no, what have you done to escalate the issue?
Not necessarily redundant. You could buy another multi, if the current one can’t be fixed. You could request the supplier to try the new unit before you buy it. Your supplier sounds like an unusually friendly and understanding person.
It’s possible that your multi is broken or your interpretation of the settings is wrong.
I was thinking this.
There ar rmany who say thigs are programmed correctly. Correct is different in the eyes of the beholder..
But are they programmed as recommended?
Setting ‘Limit managed battery charge voltage’ to 52.4v had no effect on the issue. Tested and manually stopped PV inverter. Battery 52.99v, Multiplus 53.0v and frequency was 50.7hz
I had to check. I have seen a few in the thread say it was to recommendations and then find out 50 replies down. It was not. When very specific things are asked.
With firmware has different versions beeen tried with all components on the same gen firmware?
Are there any other mods or integrations in the system. Also had an issue here where someon said no and there was a loxone there they had sent a command to the system updated it and the registers changed… Weird behaviour resulted
Is the pv inverter programmed or set to throttle netween specifi frequencies?
Can you alter the responding frequency on it to be more aggressive?
Has the pv inverter assistant been tried as you are offgrid?
Is the system using ac ignore or just switch to inverter only? When you disconnect does it set its own voltage that is different to the grid?
If you take off bms control (for shirt term testing only) does it stick to the ve bus voltages of 51 and 52v and then work correctly.
The firmware was up to date on all products as of July 2025 when the issue was reported. No updates were done whilst this was being checked and accessed by supplier etc. The software is now up to current firmware on all products. Multiplus, GX and MPPT’s
Intergrations - ESS assistant and AC current sensor assistant. There is no Node Red, HA or third party connections.
The system is ESS grid parallel. To simulate grid failure a manual AC disconnect is used. The voltage grid input is 240v then when grid is disconnected the voltage is set to 230v and as stated above the frequency instantly rises to stop the PV inverter 52.3HZ. The frequency then reduces.
The PV Inverter is a Growatt which I believe does not variable throttle and I am not aware of being able to adjust the frequency shift settings.
Regarding “If you take off bms control (for shirt term testing only) does it stick to the ve bus voltages of 51 and 52v and then work correctly.” Would this to be to test the Multiplus only or to include the DC MPPT’s. The MPPT’s have been set per Victron’s Pylontech spec. If not should I turn off DC MPPT’s disconnects and try AC charging to see if the Multiplus respects its settings ?
Yes. The mppts will follow the ve bus voltages anyway.
Really at this point i was thinking of elimination.
So the frequency rises, throttles then unthrottles. Then does not return to throttling? That is interesting. So it is working -in the regard that it is functional -just not at rhe right time.
It does mean this is eliminated as a problem as in it has a fault.
1/ Tried testing with BMS cable disconnected. After a minute or two the MPPT’s reported BMS loss and stopped. The Multiplus then reported BMS loss and then Low Battery Voltage and stopped.
2/ Tried unplugging data connection between Multiplus and GX, using MK3 USB to monitor Multiplus with VictronConnect after a minute or two the Multiplus stopped, Low Battery Voltage.
Please could you advise regarding the trigger and where the measurement and control of the Frequency shift happens (device), besides the settings in PV/ESS assistant ? Should the MPPT’s be throttled before the AC PVinverter?
To do the actual test you have to reset the bms controls on all components and let it run on voltage control only.
This will rule out the bms control.
Ve bus will require a restart
And the mppts will require you to connect to them and reset the bms control there.
It is a deliberate action and so requires extra steps to differentiate between an actual bms control loss (an actual problem) and a deliberate action for testing purposes.
As soon as you plug in the pylons again it will resume bms control so reinstating bms control is easier than removal after the teating is done.
Is the Growatt inverter connected on the output of the Multiplus2?
The Growatt needs to be set for P(f) – Power Frequency in the same range as the MP2
P(f) – Power Frequency: This is used when frequency-based power reduction is required. This defines a
graph set by two points. The PV inverter de-rates power according to the defined graph, until the
frequency reaches the trip value and the PV inverter disconnects
My Solar Edge is connected on the MP2 output side and has the Hz setpoints necessary but also needed an dry contact to be able to initiate the P(f) Hz/power slope.
In islanding situations (e.g. grid failure = emergency operation) the PV has to be controlled by the MP2 output as it was a diesel-generatorset. No load running 52Hz, full load running 50 Hz
Hi Guy, I hope you do not mind me trying to reach out to you.
I have seen your comments on an issue regarding Multiplus and frequency shifting similar to the issue I am having. You mentioned reducing the target charge voltage of the MultiPlus so it finishes charging sooner and begins to increase AC frequency while the more responsive DC MPPT solar chargers do the finishing part of the charge.
I am concerned regarding changing Pylontech with ESS settings other than Victron’s own documented recommended settings. One setting change may affect something else. eg. would reducing target charge voltage on the Multiplus effect AC charging of the Pylontech’s for a time of us tariff ?
Any advice would be appreciated, in relation to Pylontech/Multiplus/FrequencyShift.
My system has 2 Non-Victron batteries, dc setpoints and control strategy i made are not the standard Victron setpoints.
Too low dc-charge voltage will never be able to reach a 100% SoC, but when the Hz/ power slope of the Victron rises above 52Hz, the PV should be able to decrease its output power. 100% SoC or lower, the PV should decrease! If it’s not, than the PV inverter probably is not set for “generator control”
guystewart
(Guy Stewart (Victron Community Manager))
16
Is the grid reliable?
If so, I would recommend that the AC PV inverter be installed on the AC-input side with a Victron grid meter set to ‘grid’ mode and then just let the growatt disconnect when the grid disconnects.
Trying to use an AC PV inverter that isn’t explicitly supported with frequency shift is going to be a rough experience for yourself and your components. So I think it’s best to just avoid it and only use the AC PV when the grid is connected via the AC input.
I have found off grid, the ac pv starts to be throttled at around 95/96% SOC.
Another ‘trick’ was a short connect to grid let it synchronise and drop the system frequency then disconnect again. Not used all the time but when bulk loads are scheduled to switch on.
We do have power cuts. The PV inverter is in an outbuilding using an the existing underground feed and located not near the Multiplus.
Its is strange that LXonline indicates throttling starts at approx 95% which indicates a possible difference and variance.
The throttling/stopping of the PV inverter is not working per the settings, it appears. The Multiplus Frequency Shift is working instantaneously on the point of the power cut, correctly shutting down the PV inverter. The Multiplus Frequency Shift is not respecting the voltage charge settings for the batteries in the Multiplus 52v or Victron’s 52.4v for Pylontech batteries.
Please could you give guidance to why this is happening, it may benefit other users.
Reading between the lines, the issue is an unsupported PV inverter which does not respond correctly to frequency shifting. Not all PV inverters do and won’t play nicely in this setup.
The advice to move it to the input side seems like a better idea.
Always best to stick to certified and tested configs for an expected outcome. Leaving the path can be a bumpy ride.