A battery charging circuit

A circuit for charging batteries B1 - B4 comprises means for supplying a charging current to each battery, load application circuits (400) for applying a load to each battery and control means comprising a main control unit (200), charging control circuit (300) and discharging control circuit (400) for connecting the charging current supply means and load applying circuits (400) alternately to the batteries. The circuit enables alkaline and nickel-cadmium batteries to be recharged. The main control unit initially measures the internal resistance of the battery and charging is prevented if the measured value exceeds a preset value. The circuit also monitors the load voltage to determine if the battery requires charging, charging being terminated when the charging voltage exceeds a preset value or when the rate of increase of the charging voltage is less than a preset value.