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Step 7Sun tracking solar panel - Setup and ready for charging:
Portable 12 Volt, 12 Watt solar panel, a real work horse, is set up and now ready to generate power.
To quickly and accurately orient the sun tracker to true north, I prefer to use the "Sun Compass
version 1.8" (freeware), on my Palm TX pda. It's easy to initially set up: Just enter the time and select your city, from a long list on the program. And, when the program is opened, the "sun" will always appear in the exact position.
Holding the pda stylus perpendicular to the screen, to create a shadow across the screen, and
then rotating the pda until the thin shadow crosses both the "sun" and the center of the compass
rose, will provide highly accurate results.
A standard, traditional compass, even when set for magnetic declination, can all to often be
affected by nearby power lines and metallic objects, producing faulty readings. And my digital compass will not give readings if any magnetic interference is detected.
And my trusty vintage handheld GPS device will not funtion as a compass, when standing still.
Setting the tracker to the solar altitude, unlike orienting to North -or pivoting the solar panel to face the sun, is NOT intuitive. A solar altitude formula, or a solar altitude reference chart, is required to quickly and efficiently angle the solar panel to the seasonal angle of the sun. And, as the solar angle will vary wildly with the seasons, the angle of the solar panel should be carefully reset at least every two days.
Basically, the north-south rotating axis of the solar panel needs to always point north and skyward. There seems to be a common misconception that the axis always points directly to the north star, but that is not the case. The elevation of the north-south axis is always at a right angle to the sun's rays.
To orient the solar tracker to the seasonal altitude of the sun, the University of Oregon offers their "Online sun path chart program". It's the simplest, and most intuitive, I've found:
http://solardat.uoregon.edu/SunChartProgram.php
Entering your zip code will generate a chart that shows the angle of the sun, at high noon
(solar time), in your area, for different days of the year. Don't be distracted by the hours on the chart, as high noon is the only position you should be concerned about.
90 degrees, on the chart, is directly overhead. 0 degrees, on the chart, is on the horizon.
Subtracting the angle of the sun, from 90 degrees, will give you the proper angle of the solar
panel (perpendicular to the sun's rays), at high noon. The solar panel will now follow the sun, from sunrise to sunset.
Later on, I found a used Palm m515 pda, at a local flea market, for $ 5.00, and installed "RiseSet" program for the Palm OS, Version 2.1 (freeware). The program allows for setting up to 3 favorite locations with latitude, longitude, and GMT offset, to later provide a quick and easy reference for north-south orientation of the axis of the solar panel, as well as accurately setting the noon solar elevation. For noon solar elevation, just be sure to set the time for "high noon", which can be 11:00am, or 12:00pm, or 1:00pm, depending on daylight savings time. The vintage Palm m515 pda is now conveniently stored with the solar panel.
The tracker is designed to be fully functional, anywhere from the equator to the north pole. A simple modification of the clock drive position will allow it to also function in the southern hemisphere.
Also, being portable, the unit, if necessary, can be easily moved to another nearby location, to take advantage of the afternoon sun, if there is no area that receives full sunlight throughout the day.
As an added bonus, this solar tracking device could also be set up on a picnic table and used, at night, by the casual amateur astronomer. To function as a true equatorial mount, the north-south rotating axis of the solar panel needs to be re-positioned to point directly at the north star. But be advised that windy nights may blow the telescope back and forth, +/- 1 degree on the geared axis. While such tolerances are acceptable for solar panels, it is not suitable for serious astronomy.
To quickly and accurately orient the sun tracker to true north, I prefer to use the "Sun Compass
version 1.8" (freeware), on my Palm TX pda. It's easy to initially set up: Just enter the time and select your city, from a long list on the program. And, when the program is opened, the "sun" will always appear in the exact position.
Holding the pda stylus perpendicular to the screen, to create a shadow across the screen, and
then rotating the pda until the thin shadow crosses both the "sun" and the center of the compass
rose, will provide highly accurate results.
A standard, traditional compass, even when set for magnetic declination, can all to often be
affected by nearby power lines and metallic objects, producing faulty readings. And my digital compass will not give readings if any magnetic interference is detected.
And my trusty vintage handheld GPS device will not funtion as a compass, when standing still.
Setting the tracker to the solar altitude, unlike orienting to North -or pivoting the solar panel to face the sun, is NOT intuitive. A solar altitude formula, or a solar altitude reference chart, is required to quickly and efficiently angle the solar panel to the seasonal angle of the sun. And, as the solar angle will vary wildly with the seasons, the angle of the solar panel should be carefully reset at least every two days.
Basically, the north-south rotating axis of the solar panel needs to always point north and skyward. There seems to be a common misconception that the axis always points directly to the north star, but that is not the case. The elevation of the north-south axis is always at a right angle to the sun's rays.
To orient the solar tracker to the seasonal altitude of the sun, the University of Oregon offers their "Online sun path chart program". It's the simplest, and most intuitive, I've found:
http://solardat.uoregon.edu/SunChartProgram.php
Entering your zip code will generate a chart that shows the angle of the sun, at high noon
(solar time), in your area, for different days of the year. Don't be distracted by the hours on the chart, as high noon is the only position you should be concerned about.
90 degrees, on the chart, is directly overhead. 0 degrees, on the chart, is on the horizon.
Subtracting the angle of the sun, from 90 degrees, will give you the proper angle of the solar
panel (perpendicular to the sun's rays), at high noon. The solar panel will now follow the sun, from sunrise to sunset.
Later on, I found a used Palm m515 pda, at a local flea market, for $ 5.00, and installed "RiseSet" program for the Palm OS, Version 2.1 (freeware). The program allows for setting up to 3 favorite locations with latitude, longitude, and GMT offset, to later provide a quick and easy reference for north-south orientation of the axis of the solar panel, as well as accurately setting the noon solar elevation. For noon solar elevation, just be sure to set the time for "high noon", which can be 11:00am, or 12:00pm, or 1:00pm, depending on daylight savings time. The vintage Palm m515 pda is now conveniently stored with the solar panel.
The tracker is designed to be fully functional, anywhere from the equator to the north pole. A simple modification of the clock drive position will allow it to also function in the southern hemisphere.
Also, being portable, the unit, if necessary, can be easily moved to another nearby location, to take advantage of the afternoon sun, if there is no area that receives full sunlight throughout the day.
As an added bonus, this solar tracking device could also be set up on a picnic table and used, at night, by the casual amateur astronomer. To function as a true equatorial mount, the north-south rotating axis of the solar panel needs to be re-positioned to point directly at the north star. But be advised that windy nights may blow the telescope back and forth, +/- 1 degree on the geared axis. While such tolerances are acceptable for solar panels, it is not suitable for serious astronomy.
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