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Homework Help: Charing current

  1. Oct 12, 2003 #1
    Charging current

    I am total stumped on the following to questions so if someone could show me how to get started that would be good thanks.

    1) A storage battery rated at 120 ampere-hours is to be fully charged at constant current in 8 hours. Calculate the charging current.

    2) A lead-acid battery is designed to give continuous discharge of 180 amperes for 5 hours. Calculate the time it will be discharged by a steady current of 220 amperes.
     
    Last edited: Oct 12, 2003
  2. jcsd
  3. Oct 13, 2003 #2

    dduardo

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    Why don't you use the RC equations for charging and discharging? I would assume you can treat a rechargable battery like a capacity in series with a resistor.
     
  4. Oct 13, 2003 #3

    Doc

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    Hint: ampere-hours is a product.
     
  5. Oct 13, 2003 #4

    HallsofIvy

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    DDuardo, were you teasing?

    A current is measured in amperes. To go from ampere-hours to amperes, you divide by hours! Think about it.

    This is really a "proportion" problem. Let t be the time required by the 220 ampere current. Then x is to 220 as 5 is to 180.
    Or, in more modern terms, x/220= 5/180.
     
  6. Oct 13, 2003 #5

    dduardo

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    Thank you, HallsofIvy. Yes, it was a joke. I was trying to make the poor guy complicate the problem even further seeing how you just have to multiple a couple of numbers to get the solution. :smile:
     
  7. Oct 13, 2003 #6

    HallsofIvy

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    Gosh, you're evil!
     
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