Solar panel IV curve tracing

Discussion in 'The Projects Forum' started by MrBuggy, Apr 11, 2014.

  1. MrBuggy

    Thread Starter New Member

    Nov 7, 2013
    18
    0
    Hello there,

    I am currently constructing a test bench (basically a 1m^3 box) to graph the IV curve of these sunpower C60 solar cells. I've already figured out how to graph the IV curve with MPPTs(varying the duty cycle of the FET to control input voltage), obtain readings from multimeters remotely, and also how to analyze the data and make into graphs.

    The big problem now is choosing a light source that can make the solar panels give decent amount of current output. I'm not too familiar with light source solutions but a light source that has high enough irradiance to give me 1~2 amps output would be great. Lastly, it would be ideal that small amount of heat is dissipated by the light source as to not alter the open Voltage value of these cells (Voc).

    I'm looking for light sources now but if you have any suggestions, please state them here

    Thanks for your help.
    MrBuggy
     
  2. #12

    Expert

    Nov 30, 2010
    16,252
    6,751
    100 lumens is considered good for a reading light, but the sun produces 100,000 lumens. You are not going to produce that level without some heat.
     
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,281
    1,232
    Now that's a problem. Maybe the curves can be extrapolated from less current?
    There is only about a thousand watts per meter in full sun and you need 300. That's a lot of light watts. Right now LEDs have the best output for watt in, but the color might give you some trouble.
     
  4. MrBuggy

    Thread Starter New Member

    Nov 7, 2013
    18
    0
    Yea, I guess that makes sense, I can always make the tests very quick to ensure the panels don't heat up and give errors to my measurements.
     
  5. MrBuggy

    Thread Starter New Member

    Nov 7, 2013
    18
    0
    Yes, you are correct by the LEDs...
    Right now, what I have are something that are similar to these: http://reneemars.deviantart.com/art/Portable-Spotlight-202757350

    I can get an amp out of the cells, the only problem is that its too darn hot.
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    Why not used filtered sunlight?

    I don't understand why heat dissipation by the light source has any relevance. It's the panel temperature that matters.
     
  7. MrBuggy

    Thread Starter New Member

    Nov 7, 2013
    18
    0
    The test box is closed and if the light source emits significant amount of heat then the panels will heat up too
     
  8. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    Ah, got it. You should definitely record the temperature of the panel as you collect IV curve data.
     
  9. #12

    Expert

    Nov 30, 2010
    16,252
    6,751
    Solar panels get hot from the sunlight that hits them, sometimes too hot to touch. I don't see a problem unless you're going to take half an hour to measure a panel in a sealed box. Even then, that's what fans are for.

    A killowatt of heat can be limited to 50 F temperature rise with 63 C.F.M. and a $5 fan can do that if you catch them on sale.

    http://www.newegg.com/Product/Product.aspx?Item=N82E16835200049
     
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