Instructables

Portable Sun Tracking Solar Panel With A Windup Clock Drive

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I've just designed and built a homemade solar tracker than can be easily set to accurately align to the altitude of the sun (as it changes daily, with the seasons), and also faithfully track the sun, from sunrise to sunset. The tracking ability of the panel provides about 40% more power than a fixed panel. Another little-known advantage of sun tracking solar panels is that they run cooler, which enhances their output, versus rooftop mounted panels, or panels flat on the ground, which tend to build up a considerable amount of heat.

The lightweight, but sturdy device is a real workhorse, ready to provide power in the field for contractors, third world homesteads, camping trips, vacation cabins, scientifc research field stations, recharging electric powered radio controlled model aircraft, and sound systems for park events.

The heart of the unit is a standard Intermatic wall timer (Model FD12HC), with a 21 tooth spur gear mounted on the 3/16" diameter timer knob shaft, and a 36 tooth spur gear mounted on the 1/4" threaded axis that holds and rotates the solar panel. The electrical contacts of the Intermatic timer were gutted to reduce drag. The massof the lightweight 12 Volt, 12 Watt mono-crystalline solar panel, delicately balanced, slows the speed of the clock mechanism about a third of one percent.

The spur gears were ordered from:
Sterling Instrument / Stock Drive Products
www.sdp-si.com
516-328-3300
fax: 516-326-8827
Excellent schematics provided online for all gears.

21 tooth gear:
Part Number: A 1T 2-Y24021

36 tooth gear:
Part Number: A 1T 2-Y24036
 
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Step 1: Articulated foundation:

Picture of Articulated foundation:
AdjustableLegDetail.jpg
LevelsMountedOn4Sides.jpg
The foundation is designed to be lightweight, yet with rigid right angles at the corners, but is very flexible, parallel to the ground. In fact, a leg can be lifted almost 2 inches before another leg lifts. Four levels, one on each side, are required to accurately level the foundation to the ground. The photo shows the foundation knocked down for ease of stowage and transport.
azlan1873 months ago

this is great!

I wanted to know what the numbers on the rod stand for, do they correspond to the angles of the sun?
shastalore (author)  kellykelly971 year ago
Yes. Solar angle: 0 degrees is the horizon, while 90 degrees is directly above.

The lower the solar angle, the higher you go "up" the calibrated arm, to properly align the solar panel to the sun.
I have a new video on equatorial mount that you might find helpful  and also I have a picture showing a liquid piston tracker.   http://solardesign.ning.com/photo/liquid-piston-tracker
Do you think the clockwork could do the job of timing for something like the liquid piston tracker?
Brian
shastalore (author)  gaiatechnician1 year ago
Your link for this doesn't work. Could you check it out and post a correction? Thanks.
http://www.instructables.com/files/deriv/FJR/D07M/G6MPBJBQ/FJRD07MG6MPBJBQ.LARGE.jpg should help and http://images3.wikia.nocookie.net/__cb20080419182345/solarcooking/images/8/8e/800by566Water_Based_Solar_Tracker_Diagram.jpg should help too. I made the second one and it worked. But centre of gravity issues make it difficult to keep the motion even. The 2nd one should overcome any issues with centre of gravity. Actually I just looked and all my tracking ideas are on http://solarcooking.wikia.com/wiki/Solar_tracking including diagrams and some nasty old video Thanks Brian.
Do you happen to have a list of all the materials you used to make this????
shastalore (author)  kellykelly971 year ago
No, I don't have a list of materials on any of my projects, as I see all of them as experimental, and always subject to future changes and improvements.

Some of my projects are quite dangerous, if not put together properly, or carelessly handled while in use. So, in these cases, I would rather make it just a little difficult for the casual user, who might not delve deeply into the project, and might end up seriously injuring themselves and others.

I have also been approached about posting detailed schematics, with a list of materials, as well as step-by-step assembly details. But I decline, for the same reasons.

All of my projects start out with only basic sketches and ideas, with preliminary math, and any additional info gleaned from the internet (which is usually seems to be quite sparse, for all of my projects). And are then quickly thrown together, often with cardboard and hot glue, and the results carefully tested and measured. My initial math always gets me in the ballpark, but things are then quickly fine-tuned with an x-acto knife and masking tape. The experimental project is then produced from wood, using the crude, hot glued cardboard prototype for all dimensions and revisions.

My Instructables posts are mainly intended to show that such projects are possible, and also to inspire others to improve on them. And post their results on Instructables for all.
For readers who find this project of interest, you may want to see this fellow's electric sundial. I would imagine the output from his device could be used as a controller for a sun tracker.

http://pc-calculator.110mb.com/sun/digital-sundial.html
You are right. Hi has already made it by himself. See
http://personal.inet.fi/surf/atn/stracker/solartracker.html


elrodqfudp3 years ago
To make a more powerful tracker, for larger panels, you might try using the clock works from a water heater timer powered via an inverter.
Gramjen3 years ago
Wow, this looks like a great accomplishment in engineering, especially since it uses materials that can be made within an average residence. What a cool tool to be able to use. http://www.missionsupplyonline.com
Thank you for posting the instructable. 
The geared clock should be ideal for running the "clock based dripper tracker" 
I have been looking for a better clock for over a year!
Some Normal wall clocks can run it but they are so hard to take apart that most of the time I have damaged them and many of them are very weak.
The advantage of the dripper trackers is that there if the wind gets strong, your clock is not directly connected to the panel and the wind cannot damage the clock.  Also, with the dripper tracker, you clock could do the timing for several panels at once if you wanted.
If you are using solar panels, you can use a little of the power to run a 12 volt sump pump and reset the drippers at the end of the day.
Alternatively you could put several panels on one dripper tracker if you used big barrels of water instead of little buckets like I did.
Brian
pfiddle4 years ago
 This may yet prove to be a serious contender for a prize. Beaut. Simple. Workable. MY only concern is dust and dirt getting into the works. 
One way to avoid it is a trick my mother taught me - put some oiled-paper under the clockwork. It attracts dirt that sticks to it and we've often gotten clocks to start up again after years of disuse by this "trick".
Peter
Kaiven4 years ago
Cool! I was just talking about this with someone the other day, except with a parabolic food cooker!
shastalore (author)  Kaiven4 years ago
Alright! Do it! 'Cause I haven't had time to get around to it yet. But I did toy with the idea. The most promising approach seems to be a stationary black cooking pot, resting on a solid base, on a slender pedestal, with a lightweight aluminum parabolic reflector, properly angled for the latitude and day of the year, with the clockdrive faithfully tracking the sun from sunrise to sunset. But the device would also need a heat resistant glass panel to contain the solar heat, as well as a clever way to seal everything against drafts, which complicates getting the weak and tiny windup clockdrive to track everything. Be sure to post it on Instructables.com if and when you complete it.
Oh, well I didn't say I would make one. We were just thinking :P Sorry for giving up your hopes, but maybe someone would be interested in doing this for us? haha
shastalore (author)  Kaiven4 years ago
That's ok. Actually, the soIar oven possibility, I described above, was really a design for a solar water heater, with a black cylinder (with reflector and heat resistant glass) replacing the solar panel, but still carefully angled for latitude and season. If one was to build a solar oven, with a windup clock-driven sun tracker, adjustments, for latitude and season, are not needed, as the "L" shaped side view accepts all sunlight anyway. But the clock drive would require a little more planning (an eccentric cam), as a simple 180 degree rotation would not faithfully track the sun, since the axis of the pivot would be perpendicular to the ground.
Iceman944 years ago
Is there any way to scale this up to say, a 3'x3' panel?
shastalore (author)  Iceman944 years ago
I don't feel that a 3' x 3' solar panel would be a good candidate for a simple scale-up. You see, a lightweight solar panel would weigh at least 12-1/2#, and that would be too much mass for the simple clock drive to handle. Even if you were to mount two clock drives, at opposite ends of the panel, it would be straining things. And would probably be an awkward setup, juggling both clock drives and building a larger, cumbersome rig for the wide and unwieldy swing of the solar panel. And be aware that buffeting winds, on a 3' x 3' panel, will also put a damaging strain the delicate clock drives.

A state-of-the art 3' x 3' solar panel will probably generate about 85 watts, which seems extravagant for packing into a remote site or cabin. You might want to take a second look at the current usage of your 12VDC accessories and see if low drain devices are available.

My original plans called for two solar panels: 12 Volts 12 Watts each, in-line, on a longer axis, for a convertible 12 Volt - 24 Volt system. The entire rig wouldn't be much larger than my existing one. But the lightweight Russian-made panels were in short supply and I could only get my hands on one of them, at the time. I now have three of these lean-and-mean panels for my projects.

You might want to consider building two of these 12VDC 24 Watt rigs I just described. Combined, they would generate 48 Watts of power. They would also have the advantage of a lower profile (= less wind resistance) than a 3' x 3' device. And if you are truly setting up in a remote site, 2 units would provide the advantage of a redundant power system, in case one malfuntions, or becomes damaged.

I tend to favor small portable, rugged 12VDC battery power stations: One charging on the solar panel + one charging on the portable wind generator, plus one or two extra 12VDC power stations in use. That way, the portable power stations can be switched back and forth for charging, and set up in the area(s) of the camp or research station that they're needed. Very convenient.
cool, thanks. What was the approximate cost of the finished rig?
shastalore (author)  Iceman944 years ago
I don't really know how much it would cost you to build this rig, as it's homemade. Of course, once one thinks about it, our time is the most expensive commodity on these things. And the special, lightweight 12 Volt 12 Watt Russian solar panels will actually cost about 4 times what I paid for them, once they get their production up. But there are other brands out there that are readily available, are also lightweight, weatherproof, and you have many wattage / sizes to choose from.
Jalloy5 years ago
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