Solar Cell Questions

[Plaxerous]

Hi Folks,

I’m planning to buy some solar cells to solder together, and I had some questions about the process:

1. I’m going to use monocrystalline cells. They’re mainly sold as 5’’x5’’ or 6’’x6’’ cells, and are usually rated at 2.8W and 4.7W respectively. However, that’s about 0.112W/square inch and 0.131W/square inch. What’s with the discrepancy here? Is it because more area is cut off for the 5’’x5’’ cell when converting it into an octagonal shaped cell?
2. What is the ideal spacing to use between each solar cell? I’ve been told it should be between ¼’’ and 1/8’’. What is the point of the spacing/why can’t it be as minimal as possible?
3. How far has the solar cell industry gone in the past 5 years? Are the solar cells I’m buying online (think eBay, Amazon, etc.) still factory rejects, or are solar cells that are listed as Grade A actually Grade A?

Any help would be appreciated! Thanks.

[SunEagle]

Hello Plaxerous and welcome to Solar Panel Talk

I really do not have answers to most of your questions except the last one.

Just about 100% of individual cells sold by anyone anywhere will never be Grade A because Grade A cells are used in the production of factory made solar panels. Individual cells are rejected as not making the grade for a number of reason and therefore sent out to be sold for whatever that can be gotten and are advertised for whatever the seller wants to say.

Hopefully that answers the main question because whatever your build will not be made from Grade A cells.

[Plaxerous]

That is quite unfortunate. There is no manufacturer out there that sells solar cells direct? I guess the market for solar cells does not really exist.

[SunEagle]

The good news is that the manufactured solar panels have come way down in price that they are now so much cheaper it would be very hard to build a quality panel for less then purchasing a manufactured one.

If you want to experiment with solar cells to learn and understand the technology then that would be a perfect use for individual cells. But to be able to build a Grade A solar panel that will last 10 to 15 years and have the same output as a manufactured panel, it would be a waste of time and money.

[Mike90250]

There needs to be space between cells to allow the tab wire to flex and not stress or crack the PV cells, too close and they crack.
Look hard at the cells and they crack. Lift and dangle them from the tab wires and they crack.