My configuration:
3 Multi RS Solar 48/6000/100 firmware 1.25
4 pylontech US5000-1C (18.6kWh)
Cerbo Venus OS 3.63
Solaredge SE7K firmware 0004.0020.0036, at AC OUT 1
While testing from on-grid to off-grid, I encountered the following issue:
When the Solaredge generates say about 2kW during the day, and the battery is not full (<=80%) and is charging, and I switch from on-grid to off-grid, the entire Victron installation (all three inverters) goes into a protection mode for approximately 30 seconds, then restarts, and everything works off-grid as expected.
During these 30 seconds, the entire house is disconnected, and later, I see in the alarm logs that a “High AC output voltage alarm” was active on phase L1 (see also picture of the two tests).
When I perform this test in the evening, when there’s no SolarEdge PV output, the transition from on-grid to off-grid is seamless, I don’t even see the lights flicker inside the house.
Does anyone have any idea on what to do?
Does no one in the community has any experience with this?
The grid could “absorb” pretty big variations of AC power produced by Solaredge, because when you are on-grid, the AC-IN and AC-OUT of Multi RS are connected together.
In other words the grid can behave like a big dump capacitor that could absorb any power variation.
When you disconnect the grid, the Multi RS cannot do the same and absorb the Solaredge generated power and the voltage is rising with a big delta, hence the high AC alarm.
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I expected that the PV power generated by the Solaredge would be fed directly into the battery when the grid is switched off, but it seems that the Victron system does not switch quickly enough for this.
It takes a small time for Multi RS to adapt to the “new conditions”, during which the Solaredge will rise the output voltage to a level which Multi RS doesn’t like…
For example, on an off-grid Multi RS, if a big load (1-2kW) starts at some point, up until the MPPTs are catching up and generate the necessary power to cover the new load, it takes up to 20 seconds, time during which the load is powered from the batteries. Then slowly the MPPTs are increasing the generated power and catching up and also put back the discharged energy into the batteries. But nevertheless, 20 seconds is quite slow.
If something similar is happening in your case, up until the Multi RS adapts to the new conditions it may take several seconds.
Some will say that this is normal and the energy must be dumped somewhere…
But in the current era where even an entry level DSP can follow ΔV/Δt very quick and precisely, that is debatable and all depends on how the hardware/software stuff is implemented.
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Thanks for your explanation. I understand that I can’t do anything about this myself and that this is ‘normal’ behavior for an installation where a SolarEdge PV inverter is connected to the output 1 of the Victron Multi RS Solar.
