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Battery / Capacitor Question

  1. Oct 19, 2006 #1
    A super capacitor is to be designed to store the amount of energy that is stored in a typical size C nickel cadmium rechargeable battery. Use (but justify) any reasonable assumptions to calculate the energy that can be stored in the rechargeable battery.
    a. Determine the required capacitance value, assuming the capacitor can be charged to 5 volts.
    b. Determine the required capacitance value, assuming the capacitor can be charge to 100 volts.

    I know that U = .5CV, and we are given V. For a size C nickel cadmium battery, is the potential the same? I'm not sure how to tackle the problem.
     
  2. jcsd
  3. Oct 19, 2006 #2

    NoTime

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    No, the potential is not the same.
    Try looking up the battery specs on the web.
    Battery capacity is generally given in amp hour.
     
  4. Oct 19, 2006 #3

    berkeman

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    No, look up the capacity and output voltage of a C size NiCd battery. The output voltage will be approximately 1.5V (I don't know the nominal voltage of NiCd off the top of my head), and there will be some Amp * Hour (AHr) rating for the battery. A first approximation to the energy stored in the battery can be calculated by assuming that the battery puts out its nominal V for the AHr rating.
     
  5. Oct 19, 2006 #4

    berkeman

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    Doh, NoTime beats me again!
     
  6. Oct 19, 2006 #5

    NoTime

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    :rofl: I get lucky sometimes :biggrin:

    A NiCd has somewhat less than a 1.5v output.
    But, I'll let the OP look that up. :smile:
     
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