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Solar cells in parallel and series

  1. Dec 10, 2012 #1

    I am conducting an experiment whereby I have to measure the individual performance (on a per-cell basis) of solar cells on a solar panel. The panel has 20 cells, which are 4 strings in parallel of 5 cells in series each. The entire panel has a +V and chassis GND wire that I can open or close.

    I have the solar panel positioned in front of a high power LED to ensure that it gets roughly the same amount of light. (I am not looking for raw cell performance, but, rather, before/after tests).

    What is the best way to hook up a multimeter to an individual cell so I can figure out how much it has degraded? I am hitting these solar cells with things, and seeing how they perform after cracked.

    Do I need to sever the electrical connections between them so the results are not skewed?

    The attached picture shows what I am doing.

    I am not even sure what the best way of evaluating the health is. Should I be measuring with different resistances so I can get some kind of rudimentary IV curve? I do not know the intensity of the controlled light setup and I have no way of finding out what the intensity is, either. All I know is that it is the same. I am thinking that all I can do is get a good idea for how the voltage/current changes before/after damage.

    Attached Files:

  2. jcsd
  3. Dec 10, 2012 #2


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    Hi there :0

    getting at individual cells is pretty much impossible for most solar panels as the individual cells are buried in a sealing compund ... epoxy, polyeurathane etc and any attempt to get at the electrical connections of am individual cell is likely to damage it beyond usefullness

  4. Dec 11, 2012 #3
    What I have is not like most solar panels. The cells are individually placed on a PCB in a way that the + and - leads are fully visible and accessible to a multimeter. This solar panel was manually constructed, and is of the form shown in the diagram. Assume that all the wires in the diagram are fully accessible to a multimeter.
  5. Dec 11, 2012 #4
    Your goal seems to be to test each cell individually before and after damage. If that's the case, and you can't somehow disassemble the panel into its individual cells, I think I'd cover up all but one string and work on one string at a time. Use an ampmeter, a voltmeter, and a potmeter to graph the IV curve. Make sure you include the short-circuit current and open-circuit voltage in your measurement range. Short out a cell with a wire once it's damaged, before moving on to the next. What color is your LED light source?
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