Method and apparatus for battery charging

The invention provides a method and apparatus for operating a battery. The method comprises the following steps. The battery undergoing a first series of charge/discharge cycles, wherein the battery charging profile of the first series of charge/discharge cycles has a first regulation voltage. Monitoring the overall charge input and overall charge output during the first series of charge/discharge cycles and calculating the charge factor of the first series of charge/discharge cycles. The battery undergoing a second series of charge/discharge cycles, wherein the battery charging profile of the second series of charge/discharge cycles has a second regulation voltage. The second regulation voltage being determined in dependence on the calculated charge factor of the first series of charge/discharge cycles.