Battery Control System

A method and a system for controlling the charging and discharging of one or more battery packs (8) connected to a power source (7) or an apparatus (9) driven by the battery packs. The battery pack (8) comprises a number of battery cells connected to two or more terminals for establishing an electrical connection with the power source or the apparatus. The electronic system (2) for controlling the charging of the battery pack (8) and the electronic system (6) for controlling the operation of the apparatus (9) are integrated into the battery pack (8). The battery pack (8) comprises a communications interface for communicating with other battery packs (8) and generates a charging and discharging pool, where the most effective battery pack (8) to charge or discharge is charged and discharged first.