Introduction: Solar PV Tracker

For a class project (PV Design, Appalachian State, Dr. Dennis Scanlin) I decided to try making a low cost PV (photovoltaic) tracker. Being able to follow the sun's path through the sky can raise your solar panel system's output considerably (30-50%), but the argon filled ones can be a bit pricey, and seem to be a bit unsteady in wind. I looked at several different designs, looked at what materials I could find, and this is how I did it.

The panel is mounted to a frame, which is attached to two bike wheels. The wheels are mounted to a larger wooden frame, and the wheels and panel are moved by a 12 volt linear actuator. The sensor is an LED model and is purchased from Redrok Energy.

The LED sensor senses the path of the sun and tells the actuator how much to move to keep the panel properly oriented. At the front of the tracker are two legs that can be adjusted to the proper altitude for seasonal changes.

I used bicycle wheels because they are durable, strong enough to handle some weight, and best of all, in my case, free!

Step 1: What Do You Need?

Here is what I used to make this tracker, and where obtained:

*Several treated 2x4's (Lowes)
*Two wheels from a free bicycle- free or almost free bikes are pretty easy to find from the local landfill or thrift store
*A piece angle iron with pre-punched holes (Lowes)
*A 12 volt linear actuator-(~$75?)- (Ebay)
*An LED tracking sensor- (~$40)( http://www.redrok.com/led3xassm.htm#led3xforsale )
*Various nuts, bolts, screws, cable and wire -(scrounging around my workshop)

Step 2: Making the Base, and Mounting the Wheels

To make a nice, sturdy base I cut the 2x4's at angles and put them together to make two triangles. You can make them whatever size you need, depending on the size of your panels. I then tied them together with a couple of 2x4's at the base, and a couple up top. This made a nice, sturdy base to mount the wheels to.

I cut a couple of small pieces of angle iron with a hacksaw, found the mid point on the cross members, and attached them exterior woodscrews. I put the wheels through the holes, and spun them with satisfaction.

Here is a picture of the top wheel being mounted.

Step 3: Adding the Wooden Frame to the Wheels

I then mounted the 2x6 piece to the bike wheels by drilling holes through the bike rims and the 2 x 6 and bolting them together. I also used big U-bolts to clamp the rims to the board by drilling holes through the board and clamping it down tight. The board pivoted nicely on the two bike rims.

The 2 x 6 isn't wide enough to mount the panel to, so I added some smaller 2 x 4's to the top and bottom of the board, cut to the size of the panel. Each 2 x 4 board is as long as the solar panel is wide, and was attached to each end of the 2 x 6 with screws and bolts.

This allows a nice flat place on which to mount the panel. I attached small pieces of angle iron to the holes on the end of each panel, and then screwed them to the wooden frame. This secured the panel to the frame.

Step 4: Adding the Linear Actuator

I purchased the 12 volt linear actuator on Ebay. It's built to hold up in the weather, is strong enough to move however many panels I would want to add to it, and has a long enough stroke to move the panels all the way from one side to another. (I think the stroke is 8", but I'd have to double check.)

I mounted it on the one side of the frame with a through bolt, and attached it to the movable solar panel frame. To mount it to the side of the frame holding the solar panel I just used a staple on the board that moves on the bicycle wheels. A short piece of cable goes through the hole on the linear actuator and the staple, and iIused a small cable clamp to secure it. This allows everything to move around and flex as needed when it's moving. When hooked to the battery the actuator moves the panel all the way to one side, and reversing it moves it all the way back.

The next step is giving the tracker the smarts to know when and how much to move.

Step 5: Adding the LED Tracker

I wish I had more pictures of the LED tracking unit, but there is plenty of info at Redroks website. The unit uses LED's to measure the position of the sun and tells the linear actuator how much to move and where to position the panel. It's really a slick little unit, and at a great price.

Go to http://www.redrok.com/led3xassm.htm#led3xforsale to purchase one if you want to try this yourself. There are plenty of pictures of how other folks have mounted them at http://www.redrok.com/electron.htm#led3x . I put mine in an empty peanut butter jar and mounted it to a 2 x 4. I attached the 2 x 4 to the side of the unit to get the LED tracker up above the panel to give it an unobstructed view of the sun.

Step 6: Finishing It Up

This is pretty much the finished product, and it works well. I had an issue of condensation accumulating inside the peanut butter jar and had to seal it better. The size of the tracker can be made to fit however many panels you need, and there are many ways to configure a tracker like this. I hope this was a helpful, and good luck in your tracker project!

Comments

author
UNSEPARABLE+TECHSCIENTIFICS made it!(author)2017-07-15

EXCELLENT WORK MY FRIEND!!!!

author
ElmerF5 made it!(author)2017-06-13

Helios for the android can be found at the Google's "Play Store"/

It is free.

It will provide the sun's Altitude and Azimuth from anywhere on the earth 24hrs, 365days a year.

author
Simple3 made it!(author)2016-08-28

There is an easy way ati adjust your solar panel whether level or not level, any season, any sunny day, anywhere on earth, any time of day, NO MATH involved. In the center of a piece of plywood or plastic, mount a 1inch x 12 inch dowel. Place the piece on the solar panel so that the dowel is in the exact center of the array, and temporarily tape it in place. Adjust the panel until the dowel has no shadow whatsoever around it, and your solar panel is now facing head on into the sun. Remove the plywood and you will be getting the maximum output. No Calculations needed!

author
jpccusa made it!(author)2016-09-20

This would only work if the sun did not move.

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Simple3 made it!(author)2016-09-20

People were talking about what angle to set the tilt of the solar panel for different cities around the world. All of the suggestions were about using charts, books or internet sites to get the information. Yes, the sun moves and the tracker takes care of East to West settings; my simple solution takes care of North to South settings without the math or internet. You can reuse this dowel method to adjust the tilt of the panel manually just a few times a year as seasons change and the sun is at a different angle in the sky. It will be close to accurate and will avoid having to adjust the panel as often.

author
MikeM241 made it!(author)2016-08-28

Tracking the sun works during the day, what brings the panel back to the East for the next morning sun rise? I have found that over the years a clean panel is more important than being off 20 degrees. I use the same care products as my car windshield.

windshield.

author
Mjtrinihobby made it!(author)2016-08-31

I agree!

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JoeS279 made it!(author)2016-08-28

In the last picture it shows your handy work and a rack of flat panels sitting there in a fixed position. You now have a mother/master board and you just need to make pivots for the rest of them and hook them together with a tie rod that will have all of them follow the leader. All of that with only one power unit. Great write up and idea.

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arjannugteren made it!(author)2010-05-16

Is there and equation to calculate the inclination i need to set the panel to for any given place on the world? Or is a matter of guessing towards optimization?

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colinmcc made it!(author)2016-08-28

I researched this some years ago and wrote a long article on the subject of fixed tilt angles. I've cut and pasted the most important conclusions and formulas below. Hope you all find it interesting and of use.

................................................................................................................................

Books and articles on solar energy often give
the advice that the tilt should be equal to your latitude, plus 15 degrees
in winter, or minus 15 degrees in summer. It turns out that you can do better
than this – about 4% better.

Fixed or Adjustable?
It is simplest to mount your solar panels at a fixed tilt and just leave them there. But because the sun is higher in the summer and lower in the winter, you can capture more energy during the whole year by adjusting the tilt of the panels according to the season. The following table shows the effect of adjusting the angle, using a system at 40° latitude as an example. (The comparison would be a little different for different latitudes.) Each option is compared with the energy received by the best possible ‘Dual Axis‘ tracker that always keeps the panel pointed directly at the sun.

Fixed Adj.2 seasons Adj. 4 seasons 2-axis tracker
% of optimum 71.1% 75.2% 75.7% 100%

In short, adjusting the tilt twice a year gives you a meaningful boost in energy. Adjusting four times a year produces only a little more, but could be important if you need to optimize production in spring and fall.

If your solar panels will have a fixed tilt angle, and you want to get the most energy over the whole year, then this section is for you. A fixed angle is convenient, but note that there are some disadvantages. As mentioned above, you’ll get less power than if you adjusted the angle. Also, if you live where there is snow, adjusting the panels to a steeper angle in winter makes it more likely that they will shed snow. A panel covered in snow produces little or no power!

For latitudes between 25° and 50°, use the latitude, times 0.76, plus 3.1 degrees.

Adjusting the tilt twice a year
Formulas used: The best tilt angle for:

Summer take the latitude, multiply by 0.93, minus 21 degrees.
Winter take the latitude, multiply by 0.875, plus 19.2 degrees.

The best dates on which to adjust and the angle from horizontal:
Adjust to summer angle of 24.57° on March 3rd
Adjust to winter angle of 62.075° on September 12th


Adjusting the tilt four times a year
Formulas used: The best tilt angle for:

Summer take the latitude, multiply by 0.92, and subtract 24.3 degrees.
Spring and Autumn, take the latitude, multiply by 0.98, and subtract 2.3 degrees.
Winter, take the latitude, multiply by 0.89, and add 24 degrees.

The best dates on which to adjust and the angle from horizontal:

Adjust to summer angle of 20.78°on April 18th
Adjust to autumn angle of 45.72°on August 24th
Adjust to winter angle of 19.61°on October 7th
Adjust to spring angle of 45.72°on March 5th

author
RickD72 made it!(author)2016-08-28

You can do all the research you want but I would bet with this back yard project arguing about 1/2 degree is silly. Bet neither one of you could get the angle within 5 degrees

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colinmcc made it!(author)2016-08-28

RickD72, I agree that the precision isn't warranted for this particular project, but I was actually replying to anjnugteren's question which specifically asked

"Is there and equation to calculate the inclination i need to set the panel to for any given place on the world?"

On my own tracker I have no problem setting it to 0.5 degs, using a digital inclinometer.

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SoakedinVancouver made it!(author)2016-08-28

What is so difficult about adjusting a sturdy frame within 5 degree?

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filmnuts made it!(author)2010-05-16

If your panel has a fixed inclination (as the one in this Instructable does), you usually want the angle to be the same as the latitude of the panel's location.  A location's latitude is very close to the mean sun height over a year.

author
cuyler1 made it!(author)2016-08-28

filmnuts i agree with you as i laughed about your post! I used to attempt this in september on a saturday with the guys over for the football game on t.v. a lot of Einsteins after 4 brews and "i just didn't know what i was doing" say them all without any panels of their own.

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Laral made it!(author)2010-05-16

That's DEClination and you need to set the normal to the axis to the COlatitude (90-latitude).

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redrok made it!(author)2010-10-31

Some also call this Zenith Angle

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Laral made it!(author)2010-10-31

There seems to be enough confusion without adding yet another layman's term. Why not just stick with standard astronimical terms?

http://en.wikipedia.org/wiki/Declination

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filmnuts made it!(author)2010-05-16

You're arguing over semantics.  Inclination and declination are complimentary, as are latitude and colatitude (the equation you give for colatitude is the equation of a complimentary angle).  To say the inclination and the latitude are equal is the same as saying the declination and colatitude are equal; the former is just easier for most people to understand because they already know what latitude means and how it relates to their geographic location. 

Also, the original question asked about the inclination of the PV panel, not mean annual solar declination, so I gave my answer in terms of inclination.  Declination is primarily a astronomical term, and though using it here would give you the same results, it's not technically the correct nomenclature, as we are not directly discussing the sun.

author
Laral made it!(author)2010-05-17

The word is complEmentary and I'm not arguing about anything. You seem to be doing that for both of us. ;-) And yes, declination IS an astronomical term and it is highly relevant to the discussion since ignoring the solar declination will definitely reduce the overall energy efficiency. If we're not "directly discussing the sun", then what are we discussing? And no, the declination is not the same thing as the "inclination", as you put it, or the latitude, at all. Declination is the angle that the sun makes relative to the earth's equatorial plane and it varies between +/- 23.5 degrees. At either extreme, only about 90% of the light energy is reaching the cells if you don't compensate. The astronomical term "inclination" refers to something entirely different from the latitude:

http://en.wikipedia.org/wiki/Inclination

If by "inclination" you mean the angle that the axis of rotation of the mount makes with the horizontal plane then OK. You need to align the axis in your local meridional plane, that's the plane that cuts through a north-south line at your location, and tilt the axis toward the sun so it is at an angle equal to your latitude. Then you need to add the declination angle throughout the year for maximum efficiency. You can easily calculate the angles or find a table and make a simple scale that allows you to quickly change the angle for any given week.

To put it simply, for your sake, make the angle of the frame equal to your latitude and align the axis in a north-south direction.

Before replying, do some homework this time.;-)

author
Laral made it!(author)2010-05-16

Again, that's DEClination, and here's a simple equation to calculate it:

http://pvcdrom.pveducation.org/SUNLIGHT/DECLIN.HTM

You then need to add the result, which can be positive or negative, to your COlatitude to get the current angle that the normal to the rotational axis should be at.

author
filmnuts made it!(author)2010-05-16

I would not call that equation simple (yikes!), but it is helpful for finding the solar declination on a given day and would definitely come in handy with a PV panel that pivoted on two axes.  However, as I said below, this equation is not necessary, as long as you are dealing with a PV panel with fixed inclination.  The optimal angle will always be the same as the latitude of the PV panel.  It's a fact.

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Laral made it!(author)2010-05-17

Well what's NOT simple about a multiplication, a subtraction, a division, and a sine? If that's not simple to you why did you even ask if there is an equation if you are not prepared to use it?

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greenman123 made it!(author)2013-05-30

I love the idea of solar or wind energy but dont know too much about them. How much power does this give and how can it be used inside?

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DottieM5 made it!(author)2016-08-28

If you go on YouTube you can find any information you want. I put 400 Watts on a Bimini Top on our Motor Sailer and also 378 that glues down flat and you can walk on it on the roof of the cabin. Fantastic. Love it and it is easy.

author
econjack made it!(author)2016-08-28

Nice! For those who want to spend less for the system, you can build your own sun sensor for about $2 and use a $20 stepper motor to rotate the panel to track the sun. I followed the directions in Chapter 16 of the Arduino Projects for Amateur Radio book. It is an Arduino-based system using a 10W solar panel. The code for the Arduino is also included. It does not rotate for elevation, but the system was designed for using power on camping trips where elevation doesn't change much over a long weekend. Of course, you can adjust it by hand when needed.

author
LarryO8 made it!(author)2016-03-21

What 12 volt actuator did you use stroke 8 or 12 inch?

What torque? 225 lbs?

what led tracking sensor did you order from redrok?

Thanks

Larry08

author
LarryO8 made it!(author)2016-03-21

What 12 volt actuator did you use stroke 8 or 12 inch?

What torque? 225 lbs?

what led tracking sensor did you order from redrok?

Thanks

Larry08

author
clothier_bruce made it!(author)2016-01-25

Don't you need to move the panel in two axes?

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King+Ripord made it!(author)2016-01-21

Absolutely genius. thanks I'm going to try this

author
iko.lola made it!(author)2015-02-22

Hello ,

This is really awesome

but if we don't have LED sensor tracker

Can we replace it ?with what ?

Thanks !

author
winkers787 made it!(author)2015-12-07

you use photoresistors, mounted to the panel, and rotate the panel twords whichever has the higher value

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Lifeseeker made it!(author)2015-10-21

look for solar trackers here in instructible they have a few that use smaller solar cell to control the power to the motor.

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theasianbuilder made it!(author)2015-12-03

What solar panel did you use? And how much was it, and where did you get it?

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Lifeseeker made it!(author)2015-10-20

Thank you for the idea. Jere is a pic.

temp_1337468876.jpgtemp_-1107299114.jpg
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brassmonkey666 made it!(author)2010-12-09

I want to add this tracker to my solar array over the next month or two. It seems the largest consideration is going to be which linear actuator to use.

Obviously if you can find a free or cheap one from someone who is junking an old satellite dish that would be great.

But if left to buy one, other than the stroke and finding one of the appropriate voltage, how much force should one be able to exert on say, 2 45W panels and still be able to operate in blowing winds? It seems like you would want to minimize this in order to draw the lowest amount of current from your battery bank so that you gain the maximum power from your tracker and invest as little power as possible into driving the thing. Thoughts?

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LiuBigfelix8 made it!(author)2015-02-01

trackers will make you solar array work better.

sales5@vigordigital.com

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hdb111 made it!(author)2011-01-30

Should two Linear Actuators be used for a larger array? Say Four Panels?
Thanks folks.

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LiuBigfelix8 made it!(author)2015-02-01

yes, it should be

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redrok made it!(author)2012-06-12

Hi hdb111;

I think I understand what your asking:
Can one drive multiple independent linear actuators from a single tracker.

The simple answer is no. Due to friction and different weight balance they tend to get out of sync.

A better, and cheaper, method is to link multiple bicycle rims together with a cable. A single actuator moving the cable can drive quite a few panels.

Note! These multiple panels should be separated so there is minimal shadowing.
I have a Excel spreadsheet that deals with shadowing issues. See:
http://www.redrok.com/led3xassm.htm#shadowing
http://redrok.com/Shadowing1.xls

Duane
Red Rock Energy
redrok.com/led3xassm.htm

author
LiuBigfelix8 made it!(author)2015-02-01

We have produced wifi and tilt inclinometer for 15 years in Shanghai, China.


These inclinometers are used on solar tracking system such as single-axis, dual-axis, 0~360° range. There are more specifications in my computer. Once you are interested, I will send them to you.

Many solar tracking companies, such as Juwi Solar, Scatec Solar, have chosen us as a long-term supplier.

For example, Scatec Solar has built two PV plants in South Africa.

One is in Dreuenberg, which used 535 sets of our inclinometers. The other is in Linde, which used 300 sets of our inclinometers.

Our cost and quality are very competitive.

If you are interested, please let me know. Thanks

sales5@vigordigital.com

author
SolarE2 made it!(author)2014-12-18

Great work ....Solar energy is becoming best solution for Energy Crisis in the world.

http://www.uenergysolar.co.uk/

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pkalinowski1 made it!(author)2014-05-09

I was looking into solar trackers when I found your project. Very nicely done ! I would also like to point to something I have found on youtube => https://www.youtube.com/watch?v=ljTJqQYSJ8g

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Grayhawk1982 made it!(author)2014-12-12

Sometimes simple is better. thanks for the link.

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rmasre made it!(author)2013-10-30

briliant

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rmasre made it!(author)2013-10-30

u r brilaint

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metwally made it!(author)2013-05-12

cool and nice many thanks for the helping people.

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metwally made it!(author)2013-05-12

cool and nice many thanks for the helping people.

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Wunderbar12 made it!(author)2012-06-18

Hi Team,
Here is Wunderbar 12,
Just an update on my Bike tracker Project.
After building 2 and got them working by hand, I was a happy person, sending a photo to my friend a German Tool Maker, he warned NOT to build my trackers like this, as the roof is not a good environment, and he believes I must redesign the lot to do without the Bike wheels. He said you have 30 years warranty on this solar panels, and the wheels will fall apart after 3 years, when I am also 3 years older!
We started on the redesign, so far so good, when I have a array going, I am happy to post a few photos.
Yes it is NOT easy to build something low priced but high Chocolaty,
Have a good KW day! (KW stands for Kilo Watt)

author
Wunderbar12 made it!(author)2012-06-12

Hi bwiter,
Thank you very much for your WUNDEREBAR Idea. I love it so much!
I have just copied your tracker, I used my existing Alu frame. I am waiting for some panels to complete my test unit. Then I will give you some Photos.
I will build 108 trackers, as I have 9 arrays of 12 panels on my very large roof all up 30KW. My production is down to 100KW average per day. I need to get 150+KW to repay my $80,000 loan.
I adjust the angel every month, but I find I need to track East - West the panels for more production.
We got winter here in Brisbane and it is nice to work on the roof now. Can anyone help me: I will put the panels 250mm apart and join the trackers with a rod to have 12 trackers working of one linear actuator, with this nice freely movement of the bike wheel, I am sure I will get it working, the shade problem is my worry, right now in winter I find 250mm a bit to small, but I need to save some room, would 500mm be better?
Any comment would be welcome.
Thank you again, you Gays are helping me a lot with all your input.
E-mail: Solar_Lover@bigpond.com

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