Capacitor
An electronic component able to hold a charge. It can be used in the same function as batteries with the following differences :
+ a capacitor is easier to recycle than most batteries (references will follow).
+ a capacitor can provide and absorb a higher peak power.
– the voltage varies with the charging state of the capacitor (it needs an additional converter to provide the voltage of the system)
– the energy by weight capacity is less interesting than with batteries.
– the cost by energy is higher.
– the lifetime is quasi infinite (1M cycles).
The energy storage of a supercapacitor :
energy = 1/2 * C * voltage difference^2
http://www.engineeringtoolbox.com/capacitors-energy-power-d_1389.html
ex = 1/2 * 500F * (16-12)^2 = 4000J = 1.11Wh = 1 cyclist for 1min20sec
http://www.maxwell.com/products/ultracapacitors/16v-large-modules/documents
