Hello,

I couldn't find the answer to my question in the forum, so I'd like to ask it here:

I'm talking about an ESS Scenario where I can use Phase 1 as a Backup if the grid fails. (One Multiplus-II between Grid and Phase-1 Loads).

I have a Fronius Symo 5.0 and a Multiplus-II 3000. So I'd like to install 1 phase of my fronius PV on AC-OUT just in case the Grid fails. But as far as I have understood I cannot do that because the PV Inverter delivers 5KW and the Multiplus-II can only handle 3 KW.

But what I do not understand is the following: How does the PV Inverter split the energy delivered from the PV Modules on the 3 phases? And what's the maximum load that's deliverd on one phase? Let's say phase 1 is on AC OUT of the Multi, phase 2 and 3 are on AC In side. So in case of a grid failure: would the PV Inverter put the entire power on phase 1?

So let's say I add a 2nd Multiplus-II. Then Factor 1.0 rule would be OK. Phase 1 and 2 of the PV Inverter would be on AC OUT, Phase 3 on AC IN side. How would the power be deliverd from the PV Inverter in case of a grid failure? Would it deliver all power on Phase 1 and 2?

thanks,

Florian