Since about one year I have been operating a self built battery with one multiplus II 5000VA an now I want to expand to a 3 phase system with three multiplus units. Currently I have wired the remote on/of to a kind of emergency stop button in order for other people to be able to shut the system down in case this would be needed. Now I would like to switch all three units off with the same function.
On the Multiplus I don’t find the “L” and “H” designation for this connection though so it seems to me that I cannot turn the unit on by connecting “L” to ground.
My question is whether I can just connect connector J on all three units in parallel and then put the switch in between? This would create a direct electrical connection between all units though…
I would really appreciate if someone has more information on whether or not this is allowed or how to make it that I can have one stop button switch off all three units at the same time!
Rather than trying to use the remote on/off for each inverter, the recommended solution is using the safety switch assistant as described in the below post:
You need either a safety stop switch with multiple break contacts, build something with a relay or use the safety assistant
However in 3 phase setup they all shut down when using the remote on off on master
I also use 2 safety switches for my system (1 in main breaker panel in my house, and 1 in the ESS room)
but i build a custom failsafe relay controller for it that also shuts down my pylontech US5000’s
The GX will overrride the remote on off in any case. The safety switch assistant is the way. And it only wired to the master so simplifies things.
Depending on if you are classing this as an emergency stop or not, you will also need a way to shut down PV production otherwise there will still be current moving. (So using the mppt remotes as well)
The other way is to a digital input with some node red programming. But still the safety switch is better as nothing will hang or have a ‘brain fart’
use the normally closed switch (that opens on pressing the switch) in my safety stop to activate the remote on/off on the master (L1) inverter.
use the normally open switch (that closes on pressing the switch) at the same time to wire to a digital input on the Cerbo to also shut down all three units in the software as a backup / failsafe.
On the other hand I’m reading that using the safety switch assistant on the multi (master/L1) would be better than using the remote on/off. Some questions on this point:
It seems I need to use the aux input on the multi to activate the safety switch assistant: do I need to connect normally open or closed? (is the assistant activated by breaking or making the contact on the aux input?
Do I need to install the safety switch assistant on the other multis as well? Even when I’m not connecting a switch to the aux input on the other two multis? In other words: does multi 1 communicate its safety switch status to the others or do the others simply shut down because there is no three phase sync anymore?
In most cases the assistant should only be used in the master of L1, and you can define which input to use and whether it should be open or closed to activate the assistant (see below).
Just confirming that the safety switch assistant does work for everybody who might consider using it. During setup you can choose what type of connection needs to be broken or made in order for the safety stop to take effect! As a bonus you get a nice blinking LED experience when you activate the safety switch
Edit: please read my post below on the use of AUX1 as the input for the safety switch assistant.
WARNING: for everybody considering to use safety switch assistant: do not use AUX1 as the input because this is interfering with settings for the grid code where AUX1 is used to prevent grid feed in.
It took me quite some time to figure out why my multiplus was not discharging the battery anymore after implementing safety switch assistant on AUX1… I will be reconfiguring it to use AUX2 from now on.
Strangely VE-Config does not warn the user about the conflicting use of AUX1 in this case…
Edit: the above applies to grid code ‘europe’ and the grid code setting can be found in VE-Config on the tab ‘Grid’ → sub-tab ‘European grid code settings’.
