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help on lab! efficiency of solar cells?

Thursday, September 24th, 2009

for this lab, i had to make a solarimeter, which is a simple solar power meter consisting of a solar cell connected to a meter that measures electricity. the cell will be exposed to sunlight. i used a voltmeter/ammeter, a solar cell, a 9v battery to make one. what i’ve recorded as data was the voltage and current.

so i’m asked to "prepare a table and rough plot of the % of maximum voltage vs. color of incident light from the data obtained". how do i do this if i only have the voltage, current, and power (voltage x current)?

-also, if the maximum efficiency of the cell in a science lab is 30%, whereas a commercial cell (the one used in my lab) might be 4 – 15% efficient, is the cell i used comparable to the solar cell in a lab? why is not as efficient?
-if the efficiency of a solar cell is 5%, what do you think will happen to the rest of the energy?

i know i’ve asked a lot, but any help on this lab is greatly appreciated.

The only way to graph the color data is to have taken that data.(voltage and current wont be enough)

Your experiment is going to have considerable error since there will be no way to calibrate the intensity of the light.

The point of the exercise is to show you that solar cells can only capture a certain wavelength of light. I believe the largest power will be in the green wavelength(just a hunch). So to do your lab simply shine a bright light though some translucent colored objects and take readings. One color will be substantially greater than the others. Record your data and graph it in excel. Voltage will increase as wavelength decreases while current will decrease as wavelength decreases. This gives you your maximum power production somewhere in the middle(probably green 510nm).

Commercial panels are about 12-15% efficient. The rest goes into heat. I doubt your panel is 30% efficient unless you got a substantial donation from nasa :)

However as will all engineering labs, if you are within 100% your doing pretty darn good :)

Best of Luck