Control Strategy for Pulse Charge Lead-Acid Batteries for standalone photovoltaics

Lead acid batteries are still broadly used in stand alone photovoltaics. The main concerns within the use of this type of batteries are deep discharge cycles, prolonged undervoltage state leading to sulfation and, in some... [ view full abstract ]

Lead acid batteries are still broadly used in stand alone photovoltaics. The main concerns within the use of this type of batteries are deep discharge cycles, prolonged undervoltage state leading to sulfation and, in some cases, poor charge acceptance inducing gas formation during charge and active material softening. This work proposes a method to revert the battery sulfation and to reduce the gases formation using a three-step charge protocol, implemented in a bidirectional dc-dc converter. A bidirectional converter, in which the output current is pulsed with both magnitude and width controllable, is used together with constant current profiles in order to increase charge acceptance and, by that, reduce the gases formation and potentially increase the battery life.