My system setup contains 3 x MP2 48/3000 with 4 x Pylontech US5000-C, 1 phase pv on AC in and 3 phase pv on AC out using frequency shifting, which seems to work fine.
What I am trying to manage is to create a fail safe to trigger rapid shut down on the 3 phase pv when battery is 100% AND system is off grid ( AC in: off). This is to prevent shut down of Victron system or damage on devices. PV is Huawei SUN2000-4KTL.
Using Node Red and triggering relais 1 which will be connected to pv input for rapid shut down. Anyone an idea if this is possible?
Which parameters to use for Node Red, like charging status or voltage level or any other?
Because disconnecting ac can cause problems, DC of panels are still connected.
As stated in my info I want to have a soft shutdown of pv when battery reaches full status.
So I want to create this failsafe via Node Red and the Cerbo relais. So automated via software, if AC in is not present and battery full the pv on ac out must stop producing.
Frequency shifting is working, but if for some reason this method fails I want to have a failsafe method. Especially when I am not home and this situation occurs. If pv keeps producing while battery is full in off grid situation the Victron system will shut off or devices could be damaged.
The disconnect of PV is always last so it shouldnt be used as a fail safe before exploring the ac disconnected first.
As a further note, disconnecting DC is alot more dangerous than AC.
The rapid shutdown mode is integrated in the software of Huawei pv invertor. It should be enabled in software and after that 2 pins in their interface connector can be used ( short/ open) to trigger a rapid shutdown. This is a safe method to shutdown the system via a button or relais creating short/ open situation. No manual action involved to switch off the system with the regular AC and DC switch. I hope this helps understanding the rapid shutdown function.
For that then it is simple on node red. There are many examples on the forum as it is the first flow most people start with.
You could probably import one and modify it for your conditions.
You could make this a two step shutdown.
First switch off your inverter with the digital controls, then disconnect the PV strings with Eaton P-SOL20 or 30 (depending on the Isc of your strings) disconnects. They can be tripped with P-SOL-XUV-module by cutting the supply, either 24Vdc or 230Vac.
When the inverter is shut down first, there is no current through the strings, so there will be no arc inside the disconnects the will wear them down quickly.
With digital controls you mean the rapid shutdown procedure?
There is no need to disconnect the pv strings, this will be managed by the pv inverter.
My real question is how to setup Node Red with 2 dependent variables, battery full and off grid situation (ac in off). Which nodes to use, I am not very familiar with Node red yet.
So, how to shut down my pv is no issue for me. This will be only important as failsafe if frequency shifting should fail.
I hoped that someone could help on that part.