The system is configured to be in ESS with grid information BUT is used only in off-grid with a dry-contact and remote control that switches at 47 Vdc and enables the grid to feed the loads directly.
Honestly I have now doubts that the ESS might not be required and can cause problems (High DC ripple) in the system… Can anyone confirm this or is just my imagination?
As you can see from the screenshots, there is also another problem regarding the battery voltage shown in different graphs.
One more thing, in the Multiplus parallel configuration, if I have 4 kW consumption, why does the master proviedes that power from battery? I expect it to be distribuited evenly between master and slave…
ESS and off grid are incompatible, as there is usually nowhere to export or import energy to..
Not sure what you mean by this. Is this a dc controlled transfer switch? Not sure why you would want to do this, as this is internally implemented in the inverter.
Man Yi battery (LiFePO4): Does this have a BMS system that communicates to the Cerbo? It looks from the graphs that the maximum battery voltage may be being exceeded - this can lead to stability problems. The Cerbo and The multiplus can both override (limit) the max voltage if set up correctly. If the BMS can’t talk to the Cerbo, then a 2 signal relay control system should be implemented.
In the VRM reporting, two inverters in parallel are typically seen as one, the power will be shared between them.
Thanks for the response, the grid connection is “blocked” and it was already in place so I found it this way now I’m trying to understand what is going on…
The battery has a BMS that can be configured but despite this Victron reads different voltage values which is kinda weird
Are you sure they share the power? I was of that idea but somehow when a 3 kW load calls, only one inverter works and the other one kinda looks like it’s in stand-by waiting for more power to be called.
Victron has a list of compatible BMS / Battery manufacturers. IF the BMS connection is providing inaccurate data to the system due to protocol mismatch, then ESS will definitely not work and probably hinder system operation. Sorting out the BMS communication should be the first priority.
I’ve been operating parallel inverters for 5 years now, they do seem to share power equally except at very low power levels. There are two different approaches taken by manufacturers for parallel operation, one is equal sharing all the time, the other is to idle inverters until the master reaches it’s power limit. Sometimes, particularly with very large inverters, low power efficiency can be improved by loading one inverter with a second (in regeneration mode) so as the inverters are always working at a reasonably efficient power level.
