A method for dynamically monitoring a capacity of a battery includes estimating a first voltage threshold of the battery that is being discharged, wherein the first voltage threshold corresponds to a low capacity of the battery, and measuring a present voltage and a present current of the discharging battery. The method further includes re-scaling the present current based on the estimated first voltage threshold and the measured present voltage of the discharging battery, and calculating, based on re-scaling the measured present current, the battery's capacity before the present voltage level decreases below the first voltage threshold.