Earlier this year I noticed that one of my panels, A2, was having a noticeable dip in power production compared to the other panels for a few hours every afternoon. A neighboring panel, A3, showed a similar problem but to a much lesser extent. The remaining panels nearby operated normally. Even though there's a tree nearby I'd originally dismissed shading as a problem since the none of the other panels were affected, but when the engineers at Tigo looked at my data they concluded that everything was operating normally and that shading must be to blame.
A few days ago I borrowed a pole pruner from a friend and was able to remove the offending branches:
Removing those branches seems to have fixed the problem! Just goes to show that even a few small tree limbs can significantly affect solar production. From January through August that little dip cost me a total of about 40 kWh of production. That's enough to drive a Nissan Leaf over 125 miles!