Panel performance vatiation

I have an 18 panel (330watt)solar system with micro inverters and enphase monitoring system. Installed in September 2018. Panels are in 2 closely adjacent horizontal rows facing north with no shading problems. All have the same orientation(tilt 23deg.,azimuth 189deg.,location Sydney). In May 2019 while examining individual panel performance during the day I observed the following:
All panels in the bottom row gave minimal variation in cumulative solar generation during the period 8am to noon on most days.
All panels in the upper row showed very significant variation in cumulative solar generation and very significant lower levels of generation compared to the lower panel row on the same days.
When the installer was queried his response was " The panels in the upper row have a slower response initially than the lower row because of the position of the sun and its intensity at this time of the year, and that this was normal.
Is this in fact normal in a small scale domestic system like mine?

Hi @osbro

Are you able to share a photo of the install, and the figures that you have for performance?


Just got a call from the installers. It seems that when the system was installed they set up the panel locations in the monitoring program upside down ie. The upper panel was actually the lower panel.

I also have looked this morning and there is some partial shading early from next doors roof onto some of the lower panels.

I am reviewing the data again but am not entirely convinced.

Will advise later


Reviewing the revised data further I find that the panel layout has been reversed both north/south but also east/west.
The result is the data is now totally acceptable. What does this say about the reliability of one of the biggest Australian installers of emphase micro inverter solar systems!

Good thing you pulled them up on it, otherwise the installer might never have found out he was setting the data up wrong!