Capacitors have a much lower capacity of energy when compared to batteries. This is why batteries are used in applications that will need to supply energy for a longer period. Capacitors are generally used in applications where they will supply energy for a few seconds or less. Capacitors only have a limited amount of storage. When a capacitor is fully charged it can not take any more energy and the excess voltage is wasted. Capacitors cannot store charges for long periods of time. Once a capacitor holds energy for long periods of time the level of voltage will start to drop. This is due to the characteristics of the. The level of stored voltage in a capacitor can vary. What we mean by this is the amount of energy in a capacitor is not fixed. If voltage is applied to a capacitor for a period of time it may not.
