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MAXIMUM SUN

A manual solar tracker—cheap, rugged . . . perfect.

By Tom Moates

The first winter on our homestead was rough. The snows were the worst anyone could remember in these Blue Ridge Mountains of Virginia, and aside from the house being completely incomplete and without running water, the solar panels—our source of electricity—were , sitting on the ground, leaned up against a camper shell to do their collecting. When spring finally sprang permanently, mounting our photovoltaic array was a priority we could no longer put off, even though our funds were seriously depleted. No longer could we afford weeds climbing in front of the modules, tree shadows, and dog traffic—all debilitating our current generation as water pumping and clothes washing became a regular in-homestead event.

The treetops around the homestead remained bright with sunlight for awhile after the sun dropped behind the higher surrounding ridge for the evening, so it was obvious a tall mounting pole would help harness more power each day. Also, we explored the benefits of panel mounts that track the sun. The pros say that in the winter, a tracking array in an unobstructed spot produces at least 15 percent more power than a stationary model; in summer, that figure jumps from 40 to 60 percent. This is a substantial gain, but we simply couldn't afford a self-tracking mount—which would have been more than $1,000 for one large enough to house all our panels.

Carol, my wife, brought to my attention the key to solving the dilemma. "With the animals and gardens," she said, "someone is usually here—couldn't we turn them?"

Of course! A manual tracker—cheap, rugged.. .perfect. For pennies compared to the factory built self-tracker, I designed and built a manual tracker large enough to handle our current 18 panels as well as 12 additional panels we hope to add one day, and used material we already had on hand.

The design is simple. The sun makes its journey across the sky in an orbital path, so the solar array needs to track in that same way. Also, the sun tracks much higher in the sky during the long days of summer (figure the angle by subtracting 15 degrees from your latitude) than in the shorter winter days (latitude plus 15 degrees). To maximize full frontal angle to the sun, the array also needed to tilt up and down to allow for this seasonal change.

Adjust the size of the tracker in this article to fit your needs. The total area of our panels is about 60 square feet, but an upgrade to 120 square feet was allowed for, so the overall size of the tracker is 10' x 12' though it isn't all used yet.

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