A battery charger, recharger, or simply charger, is a device that stores energy in an electric battery by running current through it. The charging protocol—how much voltage and current, for how long and what to do when charging is complete—depends on the size and type of the battery being. Charge and discharge rates are often given as C or C-rate, which is a measure of the rate at which a battery is charged or discharged relative to its capacity. The C-rate is defined as the charge or discharge current divided by the. A properly designed charger can allow batteries to reach their full cycle life. Excess charging current, lengthy overcharging, or cell reversal in a multiple cell pack cause damage to cells and limit the life expectancy of a battery. Most modern Simple chargerA simple charger works by supplying a constant or source to a battery being charged. A simple charger typically does not alter its output based on charging time or the charge on the battery. This simplicity means. Since a battery charger is intended to be connected to a battery, it may not have voltage regulation or filtering of the DC voltage output; it is cheaper to make them that way. Battery chargers equipped with both voltage regulation and filtering are sometimes termed • • – battery charging device in car• • •.