Part 3.1 – Solar Panel Electrical Basics

Open circuit voltage and short circuit current, fill factor – for {solar lights}.


{solar lights} & Wind EBooks
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5 Comments on "Part 3.1 – Solar Panel Electrical Basics"

  1. Great video. Covered what it took me a week to learn on my own from trial and error in less than 5 minutes!

  2. hima kavuri says:

    how can we explain JV curve in terms of charge generation, recombination and saturation currents? For example, from the curve, can we identify charge generation and saturation points?

  3. OK so let me see if I understand this correctly – a short circuit only happens when the resistance is low beyond the open circuit threshold, correct? I mean, that makes sense and is consistent with what I know of circuits in general but I was looking at a small solar cell on Amazon and in its description it says:
    Peak Current (Imp): 70mA
    • Short Circuit Current (Isc): 75mA

    Which is a way that I'm not used to thinking about short circuits – is this saying that if I were make a circuit with a 1 amp resistor on it, that it would short circuit?

    The practical application I have in mind is to put 2 of these in series (they're 6v cells) to power a .5 amp, 12v computer fan.

  4. Brian Thomas says:

    It's a similar type of calculation as efficiency, but not quite because this "theoretical" max power you are referring to is Voc*Isc. This can never occur, but not because of imperfect conductivity or some other inefficiency, but because the solar panel cannot be shorted and opened at the same time.

    Rather, think of it like this: we are assuming that the ratio of Vm/Voc and the ratio of Im/Isc do not change as temperature and irradiance, respectively, change. If these two ratios do not change, then the product of these two ratios does not change either. So…

    (Vm/Voc)*(Im/Isc) is algebraically equivalent to

    (Vm*Im)/(Voc*Isc) = fill factor.

    Assuming the voltage and current ratios do not change with temperature and irradiance leads us to conclude that the fill factor does not change with temperature or irradiance either. Therefore we can use it to find new max power points at these other environmental conditions. Does that help?

  5. Sreya Singh says:

    Hi, I am studying solar electricity, but I don't quite understand what fill factor actually is. Is it the power efficiency of a solar panel? I understand how it is the ratio of the Max power output to the 'theoretical' max power (I think), but does this essentially just calculate the power efficiency?

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