On all my Victron Energy Multiplus II ESS setups I have a breaker at the AC IN side and AC OUT side. I use the AC IN side so it can be connected to the grid and the AC OUT to connect to all my loads. This has always been working perfectly.
Today I installed another installation just as mentioned above. But every time I switch on the AC IN breaker followed by the AC OUT breaker the AC OUT breakers pops. First I though I had made a mistake and checked and measured every wire over and over again. After a while I noticed that the Cerbo GX was showing an AC Load even when the AC OUT breaker was disabled. After a while I found the following option in Venus OS 3.5 which was not there before in previous version: “Position of AC loads” which defaults to: “AC input & output”. The other option is “AC output only”
I’m trying to figure out what this option does by looking at the documentation but it is not mentioned as far as I can tell. The change log of Venus OS 3.5 only mentions this: “AC output only feature to System setup → Position of loads, which allows to hide the Essential loads box – for systems having loads on the input only. Applies to systems with an Energy Meter only.”
Can someone tell me what this option does? Does this allow the Multiplus II to be connected with one cable instead of to over which both the input and load can be powered. In other words, allow it to be connected parallel instead of in serie? To me it feels like I need to set it to “AC output only” in my case but after upgrading my own system to Venus OS 3.5 it is set to “AC input & output” by default after the upgrade and the system works as expected, so I’m a bit confused.
The PV is on the AC IN side as it does not support Sunspec. When ever I startup the system I make sure the RCD’s for the AC IN and AC OUT are disabled, then switch the BYPASS and enable the AC IN RCD followed by the AC OUT RCD. When ever I enable the AC OUT RCD it pops.
I’ve also tried to disable all breakers (except for the MAIN) so I only have the AC IN enabled and the AC OUT still pops. Whenver I disable the MAIN breaker everything is working as expected. The whole house is powered by the battery but I just don’t have AC IN as the connection to the grid is disconnected and the PV panels are also not powered as they are on the AC IN side.
Whenever I only enable the AC IN and leave the AC OUT disabled the Multiplus starts to power the house via AC IN and the EM540 confirms this. The Cerbo GX also shows AC LOAD.
Unfortunately I didn’t do the wiring for this installation as I only connected the AC IN and AC OUT and the rest has been done by an electrician. However he confirms that everything is connected as show in above diagram.
Did you try and disconnect the Multi’s and directly wire AC-IN breaker to AC-OUT breaker ? Just to eliminate the breaker, leaving multi’s, their config and system grounding ?
Are we talking AC-OUT breaker or AC-OUT earth leakage circuit breaker ?
Phase rotation in 3-fase setup ? Floating 2/3 ?
Just putting some thoughts out there
Today we solved the issue. It turned out that the electrician make a short on the neutral. Now that is sorted everything is working. Thank you all for your help!
