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capacitor based battery replacement Answered

I was wandering how big does a normal capacitor have to be to replace a AAA battery?

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JStaples
JStaples

10 years ago

Hack A Day used to have an article on a 9v supercap battery replacement, it was even sized properly. The article is still there with a picture of the finished product, but the link to the how-to is dead.

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Tool Using Animal
Tool Using Animal

12 years ago

I'm very drunk right now, so check my work, but a AAA is 1.5 volts about 900 mah for a total of 4800 Joules. Energy of a capacitor is 1/2CV2. So solving for c you need a capacitor of 4300 Farads. Whoa, somebody check that.

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westfw
westfw

Reply 12 years ago

Sounds about right. Supercaps aren't really anywhere close to batteries in capacity yet, though they have certain other advantages...

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clasic_traveller_diehard
clasic_traveller_diehard

Reply 12 years ago

I'm assuming that size and weight is no object I'm thinking of is a set up that that produces as much juice and lasts as long as a AAA battery

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Kiteman
Kiteman

Reply 12 years ago

Again, it depends on the use, but if you want an equivalent to a AAA battery but rechargeable, maybe try a rechargeable AAA? What device are you wanting to run?

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clasic_traveller_diehard
clasic_traveller_diehard

Reply 12 years ago

there is no device i want to run I'm just curious as to how big a capacitor (or capacitors) would have to be to equal a AAA battery in electrical performance. i don't want a rechargeable battery cause those wear out and stop holding a charge eventually. as far as I've read capacitors work the same every time for a lot longer (usually until catastrophic failure ends it life).

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TheInventor
TheInventor

Reply 12 years ago

In electrical performance, you can definitely get enough voltage, I'll do some testing though to see if you an use it just as long.