An improved method for sharing power between multiple battery energy storage systems (BESS) connected to a common DC network having a nominal voltage wherein the current from each BESS is regulated based upon a voltage-current characteristic which defines an output current which increases linearly in a predetermined ratio as the measured system voltage decreases. The predetermined ratio is constant in respect of each BESS. The output current of each BESS varies based upon an external signal that varies with the state of charge of the BESS.