I have had a simple grid-tied 5kW PV system for some years.
I have recently added 3 x RedFlow ZBM2 batteries, which means a total of 30kWh, but an available usable 20kWh at any instant (allowing for maintenance strip cycle of these batteries).
I want to reserve 4kWh for my own grid-failure backup use, and export the additional 16kWh to the grid each night. I have rooftop capacity for charging the batteries.
Once the system is configured to export this additional 16kWh to the grid each night, I will know how many more batteries to install, with the ultimate goal of exporting 5kW (1Ø household limit) to the grid constantly, day and night.
As far as I can tell, I have had all the necessary hardware installed, including:
- MultiPlus-II GX 48|5000|70 battery inverter;
- SmartSolar MPPT 250|100 MC4 VE.Can charge controller (for the DC-coupled PV array I added); and
- The associated accessory hardware.
So far, the system is working correctly, charging the batteries, and providing backup power for the house, but the additional grid export is not happening yet, and I'll make the system available to the utility for FCAS once I've sorted the export out. I have not yet seen any additional grid export at all - my usual daily averages of 35kWh production / 21kWh consumption have continued unchanged.
Any suggestions for getting the additional export from the batteries happening?
