Fraser's Solar tracker thread part 1

[fraser130]

First, a big thanks to all the interest in the solar tracker I made.
Here I'm going to try and talk anyone through how to throw one together as best I can.
I'm really busy at the moment so it might take some time to finish, but it will happen, I promise!


This is it on a pole that I jam on the front using the winch to clamp it.


This is it on a dodgy stand I made up so I can put it out of the shade if the car is in the shade

Why do it?
You can get as much as 40% more energy out of your panel for WAY less than 40% of the price of the panel, and/or your panel can be smaller for the same energy, AND you don't need to keep moving the panel to face the sun during the day

I'll do it in stages, and keep adding to it as I get the chance.
First I'll give a little overview of what I've done so that those that are better mechanically and electrically can just get on and build one, others can wait and see how it develops and decide what to do later!

Anyway, here goes.......
I purchased a "led3x" controller from redrok.com it's a terrible site to navigate, but believe me the little circut is well worth it, it's about 1/4 of the way down the page, and he want's 39us$ for it, it's part number LED3XS24Vc3.

What this circut does is this:
Every couple of mins it will drive a motor either forwards or backwards depending on which sensor is getting more light, it does this for a couple of seconds, then resets and starts the timer to wait a couple of mins again.
So the end result is, the panel see-saws across the sky following the sun.
At the end of the day the panel slowly returns to face east to catch the sun in the morning!

I'm off now to take some pictures, then upload so I can link to them........ next we'll look at the motor, then we'll look at how to connect everything, and how to modify the motor

[weeds]

will be watching with interest, i have a spare solar panel sitting at home

[fraser130]

Okay, now for the motor!

As I said in part 1, the control circut outputs a forward/reverse current to move the motor in the right direction. You can use any DC motor capable of running on 12 volts, if you are mechanically minded, you may choose a completely different system to this, but please be aware YOU MUST HAVE LIMIT SWITCHES ON THE SYSTEM.(sorry for the shout, but it's critical)
I chose one of these:


They are available I'm sure from plenty of places I got mine from Melbourne Satellites.

The reason I bought one of these is 3-fold, it's weather-proof, it's all self contained and can support the weight of my 130watt panel, and probably most important IT ALREADY HAS LIMIT SWITCHES WIRED IN!

Okay, let's get on with it.

So you have the motor, it will look like this except for the output shaft which I had a mate machine up for me to replace the original, just ignore that, yours will be slightly different.


now you need to take the big bracket off (if you put it on) and remove the screw on the back that holds the little plastic disc on, then using a large philips head screwdriver, remove the four screws holding the case together (be carefull not to strip them, mine were bloody tight.)

Once you have done this, you need to pry the two halves apart (giving the back of the shaft a tap where the little screw was may help, but don't flatten the shaft, it's quite soft) I found a screwdriver at each end whilst tapping the shaft did the trick. as it comes apart watch you don't damage any of the wires and stuff in the inside
This is what you end up with (except yours will have an electronic control board in there which you don't need):


If for any reason you want to pull the output shaft out you need to take the circlip off above the plastic gear wheel, then prise the wheel off the shaft, then I think there is another circlip under it that has to come off before it can be removed.

See the small circut board on the end of the motor? If you cut the wires off at the large control board end, then separate them back to the little motor board, you can cut them all off except the top two:

The top two are the ones that go directly to the little sun tracker circut, all the limit switch wiring is built in!! Isn't that great?

Now all you have to do is work out how to connect those wires to the solar tracker circut, what I did was mount a "mini DIN" socket on the motor case, and soldered the wires to that:


Any socket of your choosing will do, the current that will be going through will be VERY small, so it's not critical, just make sure that it is a style that will only connect one way round.

Put the motor back together.

.......End of part 2

Fraser

[fraser130]

Okay, now on to the actual tracker controller.
As you have probably seen on the website you bought it from, there are many ways to mount it and protect it from the weather, I went for an electronics enclosure which I drilled two large holes in on an angle, and two small holes for the wires (i used some thin round microphone cables so they would seal the round holes) here it is:

And again:


It was a fairly tight fit, but I didn't want something bulky, I wanted it small and strong, I had to put it in sensors first, and then press the board in, I also didn't use the plug that came with the board as it made the whole thing a little big, I soldered the wires straight to the unit:


........end of part 3.

Fraser

[fraser130]

Okay, hopefully I've been clear enough so far..... now to the wiring....

If you look at the last picture of the sensor box, and position yours the same way, of the 4 connections on the sensor, the top one is the positive red(+ or red) supply, The bottom one is the negative (- or black) supply, and the two middle ones connect to the two wires that you sorted on the motor.
This circut is designed for a wide voltage range, so if you pull the supply from the actual solar panel connections, you'll be fine (assuming its for a 12v system) I put a small "mini DIN" socket straight on the connection box on the back of my panel, but of a different type to what I put on the motor:


This is VERY important as if you connect the cables incorrectly you will destroy the controller.

As you have probably been wondering "how do I mount the panel to this?"
well, that's your problem! but here is one option:


The little sensor box can be mounted anywhere on the panel or the axle as long as it moves with the panel, and the sensor "eyes" are at right angles to the axle, I just velcro mine to the top of the panel as can be seen in the second photo right back in part 1

Personally, I would do it as above, but turn the motor up the other way (like I have done, and mount it at the edge of the panel instead of in the centre, that way it can go 1/2way up a longer pole.

Now if you are sure you have the supply connected the right way round, plug it all in and put it in the sun, cover one sensor and within 2 mins it should drive the motor in a direction to move the covered one towards the uncovered one. if it moves in the opposite direction, disconnect power,then swap the two wires that lead to the motor, then reconnect power. If you find that at the end of the day it returns to the wrong side (west instead of east) you just flip over the sensor (rotate it so whichever side was facing north is now facing south ) then you may need to swap the motor wires around.

One thing that is worth mentioning, make sure that the motor can move from one extreme to the other without the panel hitting anything (including the stand and the motor itself) as these little motors are heavily geared and will do some damage either to themselves or your precious panel!!

As for setting it up when camping, you could make up a stand like I have, or get a second jockey wheel clamp for your caravan/camper and clamp a pole on that then aim the setup, it's quite simple, you point the axle to the North, and adjust the angle so the back of the axle is facing the South Celestial Pole!
It's easy to locate at night using the Southern Cross, and the Two Pointers (do a Google!!)

I have actually run a dedicated supply from my batteries to the controller, with very small speaker cable as it uses very low current, but I have been assured it can run straight from the panel it is moving.


WELL! (ahhhhh sigh of relief!) that's about it, now bring on the questions!
(I'm sure I've forgotten something)

If there is any interest, I could probably put together some complete setups that are ready for you to mount your panel on, or even supply a complete kit including panel, regulator, tracker, and an aluminium tripod for the tracker/panel to mount on.
I'm about to get a tripod for mine, I'll post pics when I get it.

Cheers all,

Fraser

[awabbit6]

This looks great. I had considered making a tracker for our panels. You have inspired me to have another look at it.
I was particulaly concerned about the power consumption of the tracking motor, but the motor you used seems to draw very little current. What was the cost of the motor?

[fraser130]

Paul, the motor cost me $99 about 3 years ago.

Don't give the current a second thought, I just looked at the rating on the motor, it draws 350mA Max at 18v, so even less at 12-14v and it only runs for 2 seconds every 2-3 mins.
Nought compared with the gains.

Fraser

[isuzu110]

I like it!

I made a much simpler version in my last year at highschool (back aways now). I'd point the panel towards north and only have movement east to west to track to sun. I used a 12V motor to drive a length of threaded rod forward and reverse. As a nut ran back and forwards on the rod, it rotated the panel east to west.

Two small PV cells separated by a vertical divider to cast a shadow on one cell drove an opamp which switched the motor fowards or backwards (east to west) so it chased an equal voltage on each PV panel.

I'm pleasantly surprised at the cost of the Geotrack. Seems value for money.

[Bushwanderer]

Hi Fraser,
Great description, including sources for components.

Best Wishes,
Peter
PS: Thanks also for the PM.

[XSiV]

Great tutorial Fraser, I have almost finished my rock sliders so now it must be time to do the solar tracker. I'm sure once I obtain my components I'll have some questions however it seems you have explained things well enough for me to make a start. Thank you for going to the effort to post this up and for the PM to let me know it was here. It's much appreciated.