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Joule heating in internal resistances of a solar cell

  1. Jan 16, 2017 #1
    Hi ,
    How can I calculate the resistive heating occurring in the internal resistances of a solar cell ? Are ohm's law or the power dissipation relation P=RI2 applicable in this case ? if not the case how can we calculate the resistive heating there?

    Thank you in advance for your help
  2. jcsd
  3. Jan 16, 2017 #2
    A solar cell or panel can be regarded as a voltage source with an internal resistance ... the voltage source , measured by putting only a voltmeter across the the output (open circuit) is fairly constant as long as there is some light ... the internal resistance varies with light intensity .. internal resistance is measured by shorting out the panel/cell with an ammeter . No danger of damage if you're ammeter can read up to 10A (there will be a small resistance in the Ammeter to be accounted for) .
    P = I squared R is the formula for heat generated.
  4. Jan 16, 2017 #3


    Staff: Mentor


    The internal resistance is the slope of the V/I curve at the operating point. As you can see above, it varies dramatically from almost zero to almost infinity, depending on the operating point.

    If your concern is the panel getting too hot, I think the direct heating of the panel by sunlight is much more than heating by internal resistance.
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