MultiPlus II 48/3000, 3-phase, ESS, Ekrano, VM3P75CT energy meter, battery. The fridge + freezer are connected to ACout1, and everything else to ACout2.
“Power cut” because ACout2 switches off (mains power is available); ACout1 supplies power. Ekrano shows nothing under “AC Active Input”, and all MultiPlus units show only the green inverter LED.
After a few minutes, “AC input 1” appears again under “AC Active Input”, and all MultiPlus units show the yellow and green LEDs as usual. However, there’s still no power on ACout2. I couldn’t find any entries in the alarm log or event log. → Restarting the Ekrano solves the problem.
Please suggest how I can find the fault or prevent the power to ACout2 from being cut off.
Most likely the system is rejecting the grid due to a quality issue that exceeds the grid code limits.
You can check this with a mk3 and by pulling charts from advanced widgets.
AC2 out is always disconnected on grid loss and takes a few minutes to activate once grid returns.
This is the expected behaviour.
ACout2 is switched off by default in backup power mode. If this has not been changed, that is normal.
The MP switches to backup power mode when the voltage or frequency at ACin is no longer within the permitted range. This varies depending on the selected grid code and other settings.
The behaviour of ACout2 can, for example, be changed using an assistant in the MP.
The grid quality is generally very good. I understand ACout2 switching off during a mains power failure (I’d be very surprised if it really was the grid), but I don’t understand why, according to the LEDs on the MultiPlus units, everything is back to normal, yet there’s still no power at ACout2. Why does the Ekrano need restarting?
The ekrano should not need to be restarted, as long as you are not powering it from AC.
AC2 has a timer, it might be 2 minutes iirc, after grid acceptance that it waits before connecting again.
There are many reasons why grid can be rejected, this is logged in the NS log on the grid tab in veconfigure using a mk3.
The rejection may be seconds but AC2 will still take 5 minutes to close the relays again.
From the manual:
A second output is available that disconnects its load in the event of battery operation. On these terminals, equipment is connected that may only operate if AC voltage is available on AC-in-1, e.g. an electric boiler or an air conditioner. The load on AC-out-2 is disconnected immediately when the inverter/charger switches to battery operation. After AC power becomes available on AC-in-1, the load on AC-out-2 will be reconnected with a delay of approximately 2 minutes. This to allow a genset to stabilise.
This already indicates that the MP was in backup mode.
The mains supply is outside the permitted range, so the MP switches to backup mode and turns off ACout2. Once the mains supply is back within range, the MP synchronises and switches back to mains power, and the ACout2 delay starts.
It doesn’t matter how long the mains supply is out of range; it could be just a 0.5-second voltage dip.
The mains is outside the permitted range, so the MP switches to backup power and turns ACout2 off. When the mains is back within range, the MP synchronises and switches back to mains power, and the ACout2 delay starts counting down.
Perhaps I didn’t wait long enough, and the power would have come back on without a restart.
How long does an event have to last for the software to log it?
Perhaps there was a transient on your supply line (a large source or load being switched on or off, or a combination of these). Do you live at the end or beginning of a section of the line? Has there been any work in your area?
If it only lasts a fraction of a second, it might not have been logged.
The switching off or changeover needn’t have happened directly at your end; it could also have come via the transformer. There are several possibilities.
I have the same issue with transient grid rejection, but don’t use AC2. Log is typically empty but you can see the vebus state change. The transient is also to short to be captured by VRM.
