Abstract: An automatic battery charging apparatus is provided with a regulated battery charger (15) and a control circuit (20) for monitoring the actual voltage across the battery terminals to control the operation of contactor (25). The control circuit includes means (50) for sensing the average battery voltage at regular intervals and means (55, 60) for comparing successive average battery voltage readings. Whenever the present average voltage reading differs from the previous average battery voltage reading by less than a predetermined amount, a signal (63) is applied to a circuit (65), and whenever a predetermined number of consecutive voltage readings have been detected, a logic circuit (70) causes the contactor (25) to terminate the charging operation.