The purpose is not to buy extra stuff, to use recycled materials or lowest cost possible to get MORE POWER!
So this is an example of how much you can gain with a little cardboard and foil.
Simple solar concentrator construction.
Also, its foldable so you can have a lot of power that can be carried around.
Step 1: Cells
The purpose is to have the same cells, the same system, but more power.
The first thing is to make sure you have room for the increased area. The finished product takes more room than the cells used to, and will not gather light at very sharp sideways angles, but when it does gather light, it will be up to 50-80% more intensity.
Step 2: Size
You can adjust the height or width of the cardboard and foil to adjust for certain weather or sun patterns.
More foil is better, so getting more complicated such as parabolic cardboard might help a little more, but flat was great for a large increase anyway.
If you need to be portable, this is great because it folds up, you could make it larger or smaller. Depending on the cells.
If it needs to be weatherproof, using enamel or other waterproofing spray after you finished building works great.
Step 3: Cut
The pictures explain it hopefully.
Step 4: Shape and Fold
Using the zip ties in this fashion allows you to adjust the strength and if you leave it a little looser it can be folded back down for storage.