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Old 03-24-13, 05:43 PM   #1
Join Date: Feb 2013
Location: mendocino, california
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Default DIM 5500 w PV Array

The following photos chronicle in a spotty fashion a single axis tracking solar array I finished recently. It took two years to design and build. It serves two residences and generates slightly more electricity than the two homes use. It is grid tied, so we use PG&E as our battery pack. The panels are 230 w Sunpower, and were installed on the array by a local company, Mendocino Solar. I built all of it myself, but I had lots of help. I used Parallax microcontrollers, and received help and guidance from the Parallax Users' Forum, from a local generous neighbor, Jonathan Peakall, and from my son, Patrick Moreland. Those are the folks who were given the daunting task of teaching me how to write code for the microcontroller. The motor, which has an additional microcontroller in it, was provided by the robotics company for which my son works. A very short video of the array working can be viewed by going on and searching "trackingQT1."

There was a good deal of welding involved, and the photo of the rocker arms shows a bit of the welding set up. I used a TIG welder for all the mild steel, which I later had galvanized, the stainless and the aluminum.

Each morning the controller wakes a bit before sunrise, elevates the array until it hits a limit switch which sets the beginning point for the day. It takes a few minutes to establish contact with a GPS satellite to determine the day and exact time, checks look-up tables that were derived from sun charts to find the correct orientation to begin the day, and sets the array to that angle. It corrects the position hourly until just after sunset when the array is returned to its steepest angle (to help prevent dust build up), and goes to sleep.

I'll be happy to answer questions, and I'll be happy to share any part of the programming code.

Last edited by michael; 03-27-13 at 09:36 PM..
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