Wind up Torch from ASDA

[Skvez]

Capacitors store electricity directly (rather than converting it to chemical energy like a battery does). There are different technologies of capacitor but a few general trends are:
· They store less energy than a battery for a given volume
· They leak that energy faster than a battery (discharge in minutes or hours rather than days or weeks).
· Because there is no chemical process required they last many many more charge/discharge cycles.
· Like all things they degrade eventually but can be expected to last decades (rather than years for a battery).

But aside from those differences a capacitor can be considered to be similar to a small rechargeable battery.