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A Battery and An Alternator

  1. Nov 27, 2005 #1
    Could you run a car with just a battery and an alternator by having the alternator recharge the battery by using the motion of the wheels and other parts?

  2. jcsd
  3. Nov 27, 2005 #2


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    Gold Member

    No, that would be a perpetual motion machine. The battery could only supply the amount of power it gave out to the alternator at the absolute most (real world must take into account inefficiencies). Now if you throw in a drivetrain to power the wheels, power is lost powering the wheels and the power retrieved from those wheels if they could switch to the alternator could only be at the most, the power needed to spin up the wheel.

    In other words, conservation of energy says no.
  4. Nov 27, 2005 #3
    Ok, then I was right when I tried to explain to my dad other reasons why it wouldn't work. Since this has been proven it doesn't work, why have people pursued it so vigourously?

  5. Nov 27, 2005 #4


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    Staff: Mentor

    Sometimes people will stubbornly refuse to learn.
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