I’ve noticed that the insolation curve calculation shape is a very good match to my system generation, so I’m pretty sure I’ve got all the angles, azimuths and other geometry described correctly - however the scale seems to be consistently under-estimating the output from the panels. I’m using 335W panels, but get very good agreement with the insolation curve if I set the panel power to around 400W instead.
See https://pvoutput.org/intraday.jsp?id=64310&sid=57175&dt=20181122&gs=0&m=1 for an example.
Panel Max Power 335W:
Panel Max Power 395W:
(Flat top due to maxing out the 6kW inverter - and I do have some minor shading in the morning, dropping that section until around 9am below the perfect line).
I’m wondering if the insolation calculation is using some form of assumed panel instantaneous conversion of energy (15%?, 16%?) which is lower than the conversion efficiency of more modern panels? (in the case of my LG335 panels, 19.6% according to the datasheet)?
If so, could this be a parameter that could be added to the System specification along with the Panel Max Power parameter, to be used in the Insolation calculation?
If not, could some other scaling adjustment factor be added somewhere to correct the insolation curve to match observed panel output on a cloudless day?