In summer I am feeding back way too much into the grid

My average consumption in summer being 70W, when nothing is switched on, when I switch ON my Energy Storage Device in Inverter Mode, it produces 400W, so I am loosing 330W getting out of my home grid circuits and wasted in a way
I have to find a way to produce less in Summer or, better, exactly what I need ...

Energy Storage System OFF => Wattson reads 72W (no loads in the house, apart phantom ones)

Energy Storage System ON => Wattson reads - 324W ! 

I am also considering changing my Battery Pack configuration to 24V, using smaller Grid Tie Inverter producing only 220W, that would be more appropriate for this