Introduction: DIY 5.2kW Solar Tracker Controlled by Raspberry Pi
A solar tracking system can increase the output of the solar farm with up to 40%. All commercial solar tracking systems I have found cost more than 40% of the total cost based on a fixed installation. Some solar tracking systems cost 2 times more than a fixed installation.
Hence it is better to buy more panels than to invest in solar tracking, unless you build the solar tracking system yourself. I set out to design and build a 5.2 kW solar tracking array, consisting of 20 panels, 260W each.
Each panel is about 1x1,6 meters, so the construction consist of 2 rows of panels, each row is about 2 meters high and 12 meters long.
The electronics I use to control the dual axis motion needs to be low cost, yet reliable. I decided to use a Raspberry Pi computer to calculate the sun position and to control the motors. The program was developed using Python, it is so easy to learn that anyone can understand and modify the program.
I spent about 6000 Euro/Dollars on solar panels, 3-phase inverter and cables.
The solar tracking system cost about 3 000 Euro. A fixed frame would cost about 1000 Euro.
I did not count my hours, but it was several days of work to build this.
The most expensive parts of the solar tracker was the linear motors, I used 4 motors (120 Euro each) and 4 drivers (50 Euro each)
Step 1: (Optional Step) Build Prototype
The prototype was built from scrap wood. It is actually two frames, one larger frame to track the suns vertical position, and one smaller frame to follow the horizontal position. The solar panel is mounted on the smaller frame.
Galvanized waterpipes are used to mount the frames and allow for the rotating movement.
An old screw driver was used as a linear motor, the Raspberry PI controls a motor driver that can set the speed and direction of the screw driver. The prototype only tracked one axis.
Materials used for prototype
- Old 12V screw driver used as motor
- RaspberryPi computer to calculate sun position and move the frame
- Parallax HB-25 motor driver to drive the motor with GPIO pins
- Limit switch to detect Home position
- 10mm threaded rod and nuts used for linear motion
- 12V DC source
- 12V to 5V converter for the Raspberry Pi to run on 12 V
All plastic parts for the prototype was made in my 3D printer.
I have attached the Python code for my prototype to this step in the instructable.
Step 2: Build the Full Scale Solar Tracker
The solar tracker frame was built mainly with impregnated 2" by 4".
A stable foundation is very important. Depending on the ground conditions, you might want to dig or make concrete foundations. I used a mix of both since I found bedrock on some locations while digging.
I will continue to write on this instructable when I have a moment to spare.
I have the code, the bill of materials, drawings, lots of photos.... Let me know if you have questions.
The system has been online since august 2016. The production is displayed here: http://www.solarmanpv.com/portal/Terminal/Terminal...
Step 3: Configure the Raspberry Pi
Follow these steps to configure your Raspberry Pi
- Install Raspiban for Raspebrry Pi
- Download and install bitwise SSH on your PC (To remote control the Pi)
- Set time and date
- Set time zone
- Enable NTP so the time is always correct
- Enable wireless
- Disable ipv6
- Install Python 3.5
- Install Pysolar (Calculates the position of the sun based on the date and time)
- Install RPI.GPIO
- Create a program to control the solar tracker, or let me know if you want mine.
I use an apache2 web server and run parts of my application as a Python CGI in order to remote control the applicaiton. This way any device with a web browser can be used to control the application.
The plastic parts in the picture was made in my 3D printer.
Step 4: Let Me Know If You Need Any Further Information
More pictures and a video will be added soon.