Dear community,
recently I have expanded my installation from 3 to 6 Multiplus II 3000 3 phase in use with grid. The new ones should be compatible with the old ones (both are newer HW vesions, all have same FW version). I did all the needed setup like ESS, etc. All my load is on AC OUT 1 of the multis.
When in off-grid everything works well. I turn on load, in a few seconds it shows it as AC loads in Cerbo as expected.
The trouble I ran into is weird behavior when the installation is on-grid. When I turn on the load, Cerbo shows only 50-70% of the real load as AC loads and something from grid.
When exporting to the grid the numbers don’t add up. In the attached picture you can see one situation, when export was 1500 W, load was 900 W (in reality 200-300 W) and DC consumption was 1800 W. That does not add up by far. All 3 phases have similar behavior.
When changing the grid setpoint in ESS, the more away from 0 it is, the more weirdly the whole system behaves. This also applies to more load or more power from or to grid.
Based on data from VRM in one month I exported 8 kWh. But according to my utility provider I exported 53 kWh in that month.
It made sense to me, that there may be some problem with AC wiring resistance so I checked it and it is the same for both multis on each phase.
Has anyone experienced anything like this?
Thank you for any suggestions.