Living Sustainably
in the shadow of climate change
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05/03/13
Tilt adjustment
Filed under: General, Solar Power
Posted by: Guy @ 7:16 pm

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!

2 Responses to “Tilt adjustment”

  1. rj Says:
    Nice. I wonder if wind loading will be a problem either to the panel or to the attachment points? The animated jpg was great.
  2. Guy Says:
    I bolted the wall brackets to the wall with 3/8″ stainless lag screws, and the panels are tied in with 1/4″ stainless hardware so they ate well secured. But yes, wind is a concern and I’m considering replacing the arms with a linear actuator like those on RV awnings so I can adjust seasonally without climbing on the roof. I would install TILT OUT and TILT IN buttons inside next to the window.