I support your figures. However, my efficiency of my inverter is 98% rather than 90%. I'd also clarify that the average during winter is a lot less than 20kWhr

I support your figures. However, my efficiency of my inverter is 98% rather than 90%. I'd also clarify that the average during winter is a lot less than 20kWhr/day ... I know you said it was a maxinum :) It's most probably about 14kWh for me.