I recently bought four really cheap 0.6W-0.7W, 6V solar panels from eBay and they worked well when I tested them on their own. So I decided to use all four of them to make a small solar panel to power small projects.
I coupled up the four solar panels, two in series to create ~12V and the two pairs in parallel to double up the current. For now I drilled a couple of holes in an old doorbell enclosure and fixed the solar panels on to it.
Quick tests revealed that in direct sunlight it was able to provide an open-circuit voltage of about 13.5VDC and a short-circuit current of about 0.3A. This was alright for some small projects.
On my workbench I made a small hub which allows me to see the current voltage delivered by the solar panel. I can also use a switch that I fixed behind the unit to toggle between solar power and fixed 12V DC output from a power pack.
I have not yet added a storage battery to the project. I intend to keep working on this project and make it better. At the moment it passes through a buck converter and charges up a few 9V batteries during the day time.
The solar panels that I bought from ebay were working properly but they were not delivering enough power to do anything useful. So I decided to purchase a few more solar panels and improve the project.
The four solar panels in the bottom are repurposed from the previous project and as you can see these solar panels do not last very long in the outdoors.
