We are currently planning an energy storage system for a site with three buildings, each of which has its own grid connection and one or more PV systems.
The idea would be to operate a three-phase ESS with MultiPlus 2 units in each building, all of which would use a shared battery bank consisting of 20 Pytes V5 batteries at 5.12 kWh each (all the MultiPlus units would be located in the same building). This would allow electricity to be shifted between the buildings and used wherever it is needed.
In theory, I would now set up one system with a Cerbo GX and three MultiPlus 2 units in each building, all using the same BMS for the Pytes V5 batteries.
The theory seems simple, but is something like this possible without major problems? Has anyone perhaps successfully implemented such a setup?
Hi. Your post is confusing. Maybe something lost in translation.
You have a multiplus in each building but all multiplus’s are in one building?
Perhaps add a wiring diagram showing the layout.
Independent systems cannot share one battery.
I ran a similar system for a while. Somewhat smaller, but similar.
I would run one system as the master (main system). The other two systems as standard “zero-export” systems. A SmartShunt between the battery and the secondary systems, and feed the consumption into the main system as DC consumption.
I don’t know whether that’s the sort of setup you have in mind?
All three systems should also continue feeding excess PV power into the grid, so zero export isn’t possible.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
7
You need three separate systems, each with its own GX device and battery bank. They will be operated independently. Victron does not support what you are asking.
Ok. You could wire it that way, with custom integration, but you are on your own with no support.
Not something an official Victron forum can recommend, certainly not for any professional.
You lack the knowledge in this specific area. There is good reason this isn’t advised, but if you accept that risk, it is your choice.
Be aware that there is no warranty etc, your company needs to accept that.
I would suggest you consult one of the many experienced victron partners in your region.
I’d do a bit more tinkering and gather some information.
I’m just an ordinary user myself, so I can only describe how I would have—or did—solve it. As mentioned above, I had a main system for a semi-detached house consisting of a three-phase system, and supplied the other half via a single-phase system as well. However, I don’t think it will work without the master-and-slave principle, because only one system can manage the shared storage. In principle, what would be wrong with having the master handle the actual grid feed-in on its own?
