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.