I decided to purchase 3 Victron Multiplus-II 48/20000/250. Becuase of factor 1.0 rules I have to stack two of those Victron in parallel to make 40 kW combined to AC couple my 27 kW solar array using PV Inverter Assitant.
However where I live I won’t qualifiy for grid feed in, the capacity of the 40 kW inverter exceeded the mandated limits of 20 kW. This is where the third unit comes in, if I connect only a single Multiplus-II 48/20000/250 to our local grid I will satisfy the requirments.
This single unit will be completely isolated from the other two Victrons except they are DC coupled to the same battery bank. All the loads are on the AC coupled 40 kW system there are no loads on the single 20 kW inverter its only purpose is to backfeed the gird or use grid to charge the batteries.
How do I configure this with ESS to backfeed the grid when there is excess PV on the DC bus to prevent the 40 kW Multiplus-II from frequency throttling the solar system?
Hi and welcome. Sharing batteries is something that Victron doesn’t support. It can be done but you are on your own doing it.
A GX cannot manage independent systems, one is for monitoring only, though you can now control it with DVCC as a battery charge source.
What you are trying to do does not work with ESS, you will need to use customisation through nodered or similar to force a negative grid setpoint but that is a topic for the modification section or nodered.
You can force grid current limits and export limits on the parallel system to restrict it to 20kW, but that may not satisfy the local regulations.
Hi Nick, thanks for the reply and the welcome. Yes its the nameplate rating of the grid connected Inverter that needs to satisfy local regulations not configuration limits. I look at my nodered options, thanks again