- #1

spaceball3000

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I read on another forum, some person says (read below) when you charge one cap, then discharge into another, there is 50% efficiency loss?

I think this is wrong, as the only losses I can think of, are due to the caps ESR when there is a voltage difference between the caps. Can someone help show his\her Math is wrong..

Also you lose 1/2 the energy in this process.

I can illustrate with a little math

Given capacitors C1 and C2 of the same size (C). One charged to V and one uncharged then the energy stored is

1/2 C * V *V

If you hook these two capacitors in parallel then they will settle (after a current pulse) to a voltage in each of 1/2 V. The energy in each will then be

1/2 C * 1/2 V * 1/2 V

or 1/4 of the original energy in each capacitor for 1/2 of the original energy.

I think this is wrong, as the only losses I can think of, are due to the caps ESR when there is a voltage difference between the caps. Can someone help show his\her Math is wrong..

Also you lose 1/2 the energy in this process.

I can illustrate with a little math

Given capacitors C1 and C2 of the same size (C). One charged to V and one uncharged then the energy stored is

1/2 C * V *V

If you hook these two capacitors in parallel then they will settle (after a current pulse) to a voltage in each of 1/2 V. The energy in each will then be

1/2 C * 1/2 V * 1/2 V

or 1/4 of the original energy in each capacitor for 1/2 of the original energy.

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