Hello AAC,

Due to the recent black outs in my area,I have been considering building a mobile solar charger.(a thread for another day)

Looking around here and the net I've come to the conclusion to get the most bang for the buck, at least a single axis tracker is needed.

So further net poking I found this http://www.youtube.com/watch?v=aSyScg9VRa4&feature=related

And another on same system http://www.youtube.com/watch?v=zSEOWOam0vg&feature=plcp

It is almost to good to be true,no batteries,no controller,no sensors it's all in one so to speak.

If it's wired the way I am imagining it,well I don't know......

See any issues w/ it?

 

There's no description but from looking at it, I'm going to assume that the way it works is that the panels on one axis are wired to both sides of the motor for that axis. When one panel is receiving more light, it puts out more voltage and there is a potential difference across the motor, so the motor turns, until both panels receive the same amount of light, hence equal voltage output, and no potential difference across the motor so it stops. Same thing on both axes. Pretty cool idea, I've never seen it before. Most times people use sensors and opamps or microcontrollers to drive the motors to the correct position. That seems overcomplicated now after seeing these videos.

All that being said, I think this simple system will have the same problems as the more complicated simple light sensing systems do. If someone parks a car near it and the glare hits the panels they might behave erratically. Rolling clouds might make the panels oscillate.

When I was looking into making a panel tracker last year, The most "fool proof" system I found ran on arduino and would calculate the position of the sun based on date, time, position, and azimuth of the sun. It would stay absolutely perpendicular to the sun even if a massive thunderstorm passed overhead.

 

A simple mechanical system using a clock mechanism could eliminate all that. Add a µC to compensate for time of year drift it could be quite reliable.

 

Ikr, simplicity defined...

And that is what bugs me,nothing can be so simple,at least not in my mind.

Has to be something horribly wrong w/ it....

Think there would be problems with cell heating?

Perhaps due to a slight mismatch in cell or extremely low coil resistance?

I don't know,just gotta be a hole in this thing somewhere,want to find it before I build it.

 

FWIW I don't think the videos are "fake" and I don't see why it couldn't be done that simply. I don't see any glaring "holes" in it.

 

Some of the farmers around here use mechanical heat driven solar trackers, sold commercially. They have two black painted resevoirs both linked to a bidirection piston that rotates the mount. If the sun is at an angle it makes one resevoir hotter and more pressure so the whoel mount turns.

I assume they would have those devices in the USA too?

 

Some of the farmers around here use mechanical heat driven solar trackers, sold commercially. They have two black painted resevoirs both linked to a bidirection piston that rotates the mount. If the sun is at an angle it makes one resevoir hotter and more pressure so the whoel mount turns.

I assume they would have those devices in the USA too?

Sounds interesting,all my solar tracking prowling haven't seen one.

 

So i started digging around in my junk boxes and came up w/ this motor

http://www.hmimotors.com/New_Pages/3440.htm (6V. model)

Made in America,there is something you don't see to often.

Problem is,I haven't any cells w/ the correct specs to power this thing.

I need at least 2 cells,small as possible that can output sufficient current and voltage even on over cast days.

They need to be as lightweight as I can get them as the primary bat. charging cell is 10oz. un mounted.

Any suggestions on what and where to buy such panels?

 

I assume they would have those devices in the USA too?

They are called Track Racks by Zomeworks Corporation.
http://www.zomeworks.com/

creakndale

 

Thanks, that looks like the units I have seen, but for some reason I had the impression the 2 resevoirs were driving a piston to move the device, the "Track Racks" use gravity and the displacement of the liquid.

 

Start with torque requirement to move the panel, might be around 50 oz-in for 4' X 4' [ pure speculation ]. I like worm drive for final, at least a substantial gear for final.

 

Here's a simple cct using two green LEDs as photo sensors to track the sun and a cheap solar path light to detect dusk conditions and return the panel to dawn position.


covering the path light with the hand allows a manual rewind if necessary.

http://piments.com/solar/tracker.svg