A Battery Powered Energizer System needs a constant current.
If not recharged, the battery will eventually become completely discharged and the Energizer will stop working. The amount of current required by an Energizer increases with the size of the Energizer. The amount of charge stored by the battery is measured in Amp-hours (Ah) and increases with the size of the battery. A battery should be chosen which is designed for regular charge and discharge cycles and for discharging most of its capacity without damage.