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capacitor control Answered

I was just wondering if anyone knows any methods of controlling the energy discharge from a capacitor..

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nuncoop (author)2007-09-25

is it possible to hook up a large number of (ultra)capacitors and use them to power a small electric motor?

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LasVegas (author)nuncoop2007-09-25

Yes. You could do it with just one also. That's how those little cars, that "refuel" with a battery pack, work.

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nuncoop (author)LasVegas2007-09-25

alright but say i wanted to gut the combustion engine out of a car and replace it with an electric one, any idea on how many capacitors might be required to give it a decent amount of stamina?

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LasVegas (author)nuncoop2007-09-25

None. It's difficult enough with high capacity batteries. Capacitors would never suffice for this purpose, unless all you want is a big burst of power and then coast the rest of the way...

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nuncoop (author)LasVegas2007-09-25

Is there any way to spread that high burst of power over a longer period of time, via clever circuitry?

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LasVegas (author)nuncoop2007-09-25

I imagine with enough capacitors and an unacceptable waste of energy, one could, but it just wouldn't be practical. Batteries hold more power, distribute it more efficiently and are much lighter.

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nuncoop (author)LasVegas2007-09-25

correct me if i'm wrong, but i was under the impressions that capacitors (being essentially immortal) create much less waste in terms of energy, and that new advances in the field of aerogel and nanotube capacitors will allow it to bridge the energy storage gap. when you say much lighter, do you mean that capacitors of equal energy density to batteries are heavier?

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LasVegas (author)nuncoop2007-09-25

Capacitors are not batteries and are not interchangable. While capacitors will hold a charge, what they hold is a difference in potential from one conductive plane and another. Anything you use to try to adjust the release of that potential is simply going to absorb (waste) some of that power. If it were practical to run a car from a capacitor, it would have been done long ago. Man actually had capacitors long before batteries.

As quoted from an article at PhysOrg.com, "While capacitors might not be capable of storing as much energy as batteries of the same size, they could be much better at delivering more energy over a short time"

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Goodhart (author)2007-09-24

or if you need adjustable control, try a potentiometer (adjustable resister).

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LasVegas (author)westfw2007-09-23

Short and to the point! I like that! :)

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