Timed battery charger

Abstract

A charger 10 includes facility, such as a capacitor 14, for establishing a constant current source which is rectified by rectifier 16 to provide a supply of charging current at a single level in each of two successive periods of a charging cycle. The output of rectifier 16 is coupled through a SCR 26 to a battery B to be charged. Under control of a timer 28, SCR 26 remains conductive for a prescribed continuous period to facilitate the supply of the single-level charging current to battery B during a full charge or first period mode at a 100% duty cycle. At the end of the prescribed first period, a timer 36 then controls the on-off operation of SCR 26 to facilitate the supply of the single-level charging current during a trickle charge mode at a 20% duty cycle. In an alternative embodiment, a charge 100 includes four timers 118, 120, 122 and 124 which provide for three phases or modes of operation in which a single-level charging current is supplied to battery B at a duty cycle of 75% during a first of the three periods, at a duty cycle of 100% during a second of the three periods and at a duty cycle of 12.5% during a third of the three periods.