pv grades

AmDDAmDD Registered Users Posts: 5
Ive been looking around, reading and learning as much as I can here and I keep seeing people refer to different grades of PV's (are all solar panels called pv or just specific ones?) whats the difference in them? I assume A is the best, but why? whats makes it an A over a B?


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: pv grades

    PV = PhotoVoltaic cell. Turns light into electricity.

    As for the other part of your question ...

    Are you wondering about the difference between Amorphous, Monocrystaline, and Polycrystaline?
    Or the fact that panels are sometimes sold off as "Grade 'B'" - wherein they're not "up to snuff" so what would have been, say, a 200 Watt panel only puts out 190 Watts in testing? Or the sometimes blemished "2nd's" that are offered occasionally for reduced price?

    (And I must note here that once again the turkey who did the Glossary left out those panel terms. Ooops! That was me, wasn't it? :blush: )
  • AmDDAmDD Registered Users Posts: 5
    Re: pv grades

    Haha, looks like someone is trying to get fired. :P

    I assume it would be the "not up to snuff" panels. An example is on this page: http://sunelec.com/index.php?main_page=index&cPath=5&page=1&sort=3a the very first panel is a "Grade B".

    Since you brought it up, what is the difference in Amorphous, Monocrystaline and Polycrystaline? I remember seeing on Discovery channel or maybe History that new solar cells were in development that could use the whole light bandwidth to generate electricity, not just the visible light spectrum. Do they have something to do with that or am I way off?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: pv grades

    They can't fire me 'cause I'm not employed. We're all just volunteers helping out as best we can, with Bill and Niel serving in the supreme position of Moderator to keep things under control. :D

    Off-hand I'd say the panels you linked to are just blemished or 2nd's; might be slightly under the rated power or be discoloured or something. Without an actual explanation from the vendor, "Grade B" could mean just about anything in their book.

    In practical terms, monocrystaline and polycrystaline are interchangeable. Amorphous are somewhat less efficient (18% max for crystaline, about 9% max for amorphous - with variations of course).

    The monocrystaline would have the best efficiency; they are literally "all one crystal" per cell; no 'edges' to interfere with the conversion. Polycrystaline would be slightly cheaper, as they are multiple crystals touching each other; easier to make. Amorphous are the least efficient because the silicon isn't "neatly lined up" so to speak, but very cheap to make.

    It basically comes down to the way the silicon crystal is made, lined-up, joined as it were. All-in-one (mono) is efficient but more difficult and therefor expensive to make, followed by "ordered multiple crystals" (poly), followed by "random crystals tied together" (amorphous).

    Okay, the engineers can pull their heads out from under the pillows and stop wincing at my over-simplified explanation now. :p
  • AmDDAmDD Registered Users Posts: 5
    Re: pv grades

    Alright, thanks for the help! Im sure Ill come up with more questions sooner or later.
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