0 and 40 depending on location? We get 6Wh per W installed per day annual average here. We couldn’t get that is 40% was the max. We get 1 to 3Wh/Wi/d in winter and 6 to 12Wh/Wi/d in summer

At midday on a cold sunny spring day we’ll get 105% the nameplate power

Wh/Wi/day is Watt hours per Watt installed per day