Auto sun Tracking for Solar Panels.

'Auto Tracking' will double the energy output of your solar panels.

In this project, for less than $100, we added 'sun tracking' to a 500 watt solar array!
(This array powers our Fridge and Freezer - making them 'Blackout Proof')

Home Solar Panel 

Home Solar Panel 500w Auto-tracking, relocatable.

This 500 watt array is 50kg (110lb)
yet it can be driven by a 1 watt, worm drive motor which is
powered by the small 8 watt solar panel shown in the inset above!

Sun Tracking Solar Array.< Click 'PLAY' to see the video..
Sun Tracking Solar Array for less than $99!
(YouTube video @ 'Kids2Classic')

The 'Sun Seeking' solar panels.

(eg. $20 on eBay, 12v 10 watt)
Set back to back, facing east/west. This array will drive the motor so that the apex always point at the sun.
If the sun is more on the east panel, it will over-power the west one and drive the motor to the east.
The two panels cancel-out when the sun is equally on both.

Sun-seeking Solar Panel

This accute angle is ideal for strength, it limits the 'short circuit' losses (see below)
and sets the approx 15° tracking accuracy. 

The Circuit Diagram.

Basic Circuit. 

The full circuit is shown below..
These two east/west panels are wired in a 'short circuit' mode.. But.
The accute angle between them limits the power lost in this 'short'
and the motor can still get 80% of the available power.

More Construction Notes on Page2..

Limits to Angle of Rotation.

Limiting Rotation

For stability in storms (and a few other reasons)
the array rotation should be limited to about 50° down as shown.
At sunrise/set, there is very little energy to be gained by rotating to near verticle.
(and todays panels still work well with the sun 20° off-axis.)

This requires the addition of two 'rotation limiting' mercury 'Tilt Switches'.

The full circuit - with 'rotation limits'

Full Circuit. 

The Mercury Switches and Diodes..

Limit Switches

Shown here at 50° east rotation,
the 'east' mercury switch has just turned off.
The two mercury switches are epoxied to 4mm marine ply pieces
so their individual 'tilt' angles can be adjusted.

The 'Rope Drive' system.

The video below shows the 'Rope Drive', Pulley & Motor box..

Rope Drive system

The 11 oak fingers (above) are able to keep the
7mm rope on the edge of the 7mm marine ply disk.

Click Here for the article on a 'Chain Drive' option..

Note: After 3 months of use, no wear is obvious on the rope drive or nylon gears. But we suspect that 3 years might be a reasonable life? The 'Chain Drive' option is only $30 dearer and should last 15 years.

Parts from eBay or Local..
$20 12V Motor, 1 watt 10 rpm (worm-drive) Eg. JGY370 (eBay)
$40 2x 12V 8W Solar Panels (eBay 'Hobby / Toys')
$6 2x Mercury Switches. eg SM1035 (Jaycar)
$9 Nylon Pinion gear set. eg. YG2632 (Jaycar)"

Plus.. 7mm Marine Ply and 7mm Marine grade rope.

Click for Page 2 - Construction Notes..

Tags: Kids2Classic, Solar Tracking, bm8faldt,