Buy Polycrystalline Cells
The solar cell is the backbone of your DIY homemade solar panel project. The most common types are polycrystalline solar cells which we will discuss here and monocrystalline solar cells. For more information on monocrystalline solar cells click here.
Polycrystalline solar cells are basically wafers cut from a block of silicon which is made up of a large number of crystals giving them the poly, or multi, prefix. Unlike the amorphous cells, the polycrystalline cells are rigid wafers, about the thickness of a piece of paper. They are not flexible and cannot be bent without breaking them. As a result, polycrystalline solar cells must be mounted within a rigid frame to deter cracking and fracturing. Polycrystalline solar cells are the most common cells on the market today and are what you see on the roofs of many homes.
While polycrystalline solar cells are more expensive to produce, and as a result, purchase, than amorphous cells, they are much more efficient. In fact, at 13-15% efficiency, they are roughly twice as efficient as amorphous cells. You will know you have a polycrystalline solar cell if it is a rigid, paper thin wafer with visible marbling effect of the multiple crystals.
The easiest place to find polycrystalline cells is online. There are a few places you can find them, but I find the easiest and most reliable is Amazon. Amazon is my preferred source for solar cells because regardless of who the end seller is, I know that Amazon will back the purchase and the product. It relieves some concerns I have about products never arriving from smaller suppliers and I know if something goes wrong with the shipment, that Amazon will back me. That is a pretty big deal with solar cells because they are incredibly fragile. The only drawback to Amazon is that the selection of solar cells can be somewhat limited sometimes.
There are times when I am looking for something that no Amazon suppliers seen to have. Fortunately I came across AliExpress by Alibaba.com. AliExpress is a great little website that actually links you directly to the suppliers abroad. Most cells will have free shipping but it does take longer than you might hope. The great thing about them though is that you can get EVERYTHING. They have all different sizes of solar cells, different grades and a variety of manufacturers. If you are shopping for polycrystalline solar cells or anything else for your project, be sure to take a look as they most likely have it.
A few things to know about buying solar cells though. I recommend buying Grade A or Grade B cells and avoiding the cracked or broken cells. It is true that cracked and broken cells will still produce some energy, the problem you run into is that once you have broken cells wired together, the panel can only generate as much juice as the smallest piece. This means that you are basically wasting any whole or merely chipped pieces when you run them in with the broken ones.
Cracked and broken cells used to be a way to save some money but, frankly, the savings are pretty minimal these days and I would just recommend buying the good ones.