help please reduced output on hot days

[billybee]

well factoring that maybe a little more than 3% then. but not really as i'm compairing efficiency and if i have 10 minutes less daylight from june to july so does the other system. i canrt compaire each days outputs as no 2 days are the same. that last week in may i never saw a clood for 4 days and still daily outputs were diffrent. useing pv output in may and june the diffrence between the 2 sytems was 9% in july upto date 5.5% so looks like an improvement.

 

[moggy1968]

that hits the nail on the head. To draw real conclusions unless there are vast differences is extremely difficult. There are simply too many variables. Even year on year, this may wouldn't compare with the previous may and may not compare with next may because of the unusual weather.