Underestimation by a factor of 2

[aqreed]

Underestimation by a factor of 2

[aqreed]

Thanks i ll look into it. Could you give more info?

[jaluebbe]

Thanks for the quick response. I'll give you some data to my setup and location:
110W@1000W/m2 panel:
s = 0.514 # m2
eff = 0.22
lat = 52.5
lon = 7.3
height = 30 # m above sea level
panel surface is looking south, 90deg angle to ground.
date: 2023-12-26
solarpy calculation shows about 42W at 12:00
my data shows a peak of 85W at 12:00