Mary and I live off grid, so we wanted to mount our panels near ground level, where we could easily keep the snow off (i.e., not on a two story tin roof) and adjust the panel angle seasonally, because every watt is sacred in a non-grid-tie system, especially December through February in WV. Also, the panels would be more efficient in warm weather (due to being cooler than if mounted on a hot tin roof). We didn’t want to spend a lot of money on a pole-mount rack, so I came up with a simple design that we built from treated lumber, common hardware and hinges.
Four local families have built similar racks modeled on this design (up to 24 panels – see this gallery). We have four panels, mounted in two pairs, where each pair adjusts individually. Critical joints (2×6 and 2×4 boards to 6×6 posts, hinges to beam) are made with nuts, bolts and washers through drilled holes for strength, though we did use 2 1/2″ wood screws (and a power driver) for fastening the hinges to the narrow edge of the rack joists, and to hold the 2×6 and 2×4 in place while drilling holes for bolts.
The adjustment arms should be long enough to hold the panels horizontal, so that the panel may be adjusted through a 90 degree range from completely vertical to completely horizontal.
Here’s a closeup of the hinges and adjustment arm. The bolt attaching the adjustment arm to the hinged rack is tightened just enough to be snug but still allow pivoting (tighten an extra nut against the first to lock it in place). I used 1/4″ bolts to attach the adjustment arm to a 2×4 screwed to the main posts. Each time I made a seasonal adjustment I added a new hole to the adjustment arms. After the first year of operation the adjustment arms had holes in all the required places (since I drilled new holes as necessary), so I only have to remove/re-insert 2 bolts to adjust the angle (a couple minutes at most for each rack). We’ve found that we only need to adjust the angle about 4 times per year.
The panels are approximately balanced at the hinge point, so that it takes little effort to change the angle and hold the panels steady while reinserting bolts, and there is little stress on the adjustment arms due to wind loading. (note: for best balance the hingepoint should be an inch or two below the center of the vertical-esque panel joists, since the center of gravity of the panels is several inches away from the hinge line).