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Homework Help: Converting watts to kilowatts

  1. Feb 24, 2004 #1
    Let's say, for example, that I have a common household item that is 6amps, being run from a 12v circuit, like a car battery. That would make the wattage 72, correct? What is the time frame on that? Is that 72 watts an hour? a minute? Basically, how do I convert that number, 72watts, into a kilowatt hour? I'd like to know basically, how many kwh come from the typical car battery, in a comparison for class.

  2. jcsd
  3. Feb 24, 2004 #2


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    Watts is a rate, it's 72 watts now and it will be 72 watts 3 hours from now (as long as it's still running).

    Kilowatt hour is a unit of energy. Just turn watts into kilowatts by dividing wattage by 1000, then multiply by the hours the thing is running to get kilowatt hours.

    If a device is 72 watts and it runs for 3 hours, 0.216 kilowatt hours of power is used.
  4. Feb 24, 2004 #3


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    Make that 0.216 kW-hr of energy.

    - Warren
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