Looks like eastern oriented panels should be a few yards from south oriented panels...

softdown

Got my racks made for the four 190 watt panels scheduled to be pointed to the east. 15 degree tilt per the "recommendation" by PV Watts. Took the rack up on the roof to see how things look.

The shadow cast by the 45 degree tilt south facing panels is now horrendous. At 10am, two of the four panels would be in significant shadow. This shadow was not nearly as bad a couple months ago when I designed this. The change in shadow is much, much larger than expected.

Was expecting production from the east facing panels to go past 10am....or three hours past "sunrise". Looks like I erred.

PV Watts projects 15% more production from west facing panels than east facing panels. Also suggests ~35 degree angle for west panels vs ~15 degree angle for east panels.

There is a good place to put both east and west racks on the top of a roof line. The east and panels panels will now both have a 30 degree tilt. Seems this would be far preferable to losing significant production from the east panels due to significantly being in the shadow of the south facing panels.

I knew the shadow threat existed. But I didn't expect it to be nearly this bad. Sun orientation has earned a bad bro award....or I get a bad design raspberry award.

softdown

Alright...what happened at PVWatts?  Now it is telling me that easterly panels outproduce westerly panels by about 8%. Last time I checked, westerly panels outproduced easterly panels by about 15%. It is possible that I entered the wrong azimuth (degree) I would think.