When I recently added 2 solar panels to the south wall of my workshop, it was early spring and I felt that a steep angle would be appropriate to catch the low winter sun so I mounted them at 70° from horizontal. Recently, when I looked at my performance statistics on my Enlighten web interface I noticed that I was no longer seeing a peak power of over 220 Watts on each panel. So I did some research to determine how much more power I would get if I changed the panel to a 44° tilt angle. Since I live at about 44° latitude, this should make for an ideal average angle. I found a web calculator that allows me to see the relative per module power for each tilt angle, see below:
I have animated the two tilt angle curves so you can see the comparison. This made it clear that I would gain a significant amount of power in the summer by changing the tilt to 44°, so I cut two longer pieces of angle aluminum and have moved one panel up so that I can see the difference:
Here is the proof that tilting to the the panel up to 45 degrees improves performance, this shows peak Watts at solar noon:
Now to go up there an tilt the second panel!