The true story
I started this project after buying this 100W flexible solar panel during BlackFriday last october.
These panels are quite cheap and are very light (less than 2kg). They are thus well positionned to design a portable system.
Here in Europe it was the beginning of the winter season and I very soon discovered that a solar panel rated at 100W never produces such a power in winter times...
So I started to imagine a system to harvest the most possible power from this solar panel while preserving two main objectives that I fixed to myself :
- keep it as cheap as possible (as it was for me a hobby and a way to discover real problems with PV panels before thinking to equip my house with a Pro installation)
- keep it portable, ready to go, easy to operate and light (I wanted to be able to carry this panel in the fields to recharge my Parrot Disco flying wing batteries or to use it in a camper van !)
Finally, to be honest, this project wasn't intended to participate to the Hackaday's contest.... But when I received the reminder mail (two days before the deadline) and read the objectives of this contest... I frankly believed that with no effort I was completly inline with the Planet-Friendly Power themes :
"Build a hardware solution that lowers the cost of clean energy, through energy harvesting and/or storage efficiency improvements."
In the following sections I will cover the design of
- the frame for the PV panel
- the solar tracker system
- the MPPT controller
And you will soon see how my design lowers the costs while improving efficiency of energy harvesting with solar panels !
Everything wil be open source either hardware or software, so you will be able to build your own whenever you want !
Currently I do have a working prototype, but even if a lot has already been done, there is still a lot of job to clean the code and to improve the operations. Stay tuned !
Adding a frame to a flexible panel was an absolute necessity !
Furthermore this frame should be "scalable" to be reused for the solar tracker system
I wanted the frame to be light and cheap, so I forgot using metal and jumped to a "full plastic" solution.
Considering the low cost approach I decided to build it around cheap 20mm PVC pipes used for electrical installation. You can purchase them at less than 1$ for 2m. You will need two of them to build the full frame
To assemble the frame I designed 3d printed corners and hinges.
They are already available for download on thingiverse on my account : tilting frame for PV panel
Simply insert the PVC pipes into the corners and screw all this to the PV panel using 6mm screws and washers !
Something that I would like to mention is that 3D printing is not "free" as the filament costs "a lot" !
In order to lower the price of the project and to keep the "reuse, recycle, revamp" spirit of the challenge round#2, I decided to use PET filament that I produced from plastic bottles.
So I can proudly consider that the 3D printed parts of this project are totally free (avoiding to take into account the electrical bill... considered as negligible)
This was just to tease a little, as I will for sure publish my "pulltruding machine" to the next contest
As you will see, printing with plastic bottle PET has also the advantage of strength and also it resists to very high temperature (printed at 265°C). This is important as the back of a solar panel can easily overheat at more than 60°C. So if you use PLA for parts in contact with the panel it may start to melt...
The solar tracker
Principle of operation
A solar tracker will help to follow the sun during the day and to point the panel strictly perpendicular to the sun rays.
So a "good" solar tracker must not only follow the vertical motion (elevation angle) but also follow the East/West motion of the sun during the day (azimuth angle). The structure should have...Read more »