I hope to get a battery system to offset some of my costs, but I can't forsee not being connected to the grid as backup and to sell some excess energy back anyw

I hope to get a battery system to offset some of my costs, but I can't forsee not being connected to the grid as backup and to sell some excess energy back anyway. I don't have an electric car either, so while my current solar system (6.6kW) could power my current household energy use basically year-round (if I had sufficient battery capacity), I would only be able to slow charge solely off that, so I expect I will still be buying energy from the grid once I get an EV for times I want to fast charge (probably 11kW three phase), even with the solar and a hypothetical battery.