A method for estimating an operating current I dispensed by a battery pack or cell including the steps of acquiring characterization data of the battery pack or cell, related to measured time trends of a voltage Vm and of a characterization current Im of the battery pack or cell, associated with a respective characterization temperature value Tk; and then processing the characterization data to determine a plurality of parameters P of a model of the battery pack or cell, as a function of temperature and state of charge SOC. Measuring an operating voltage V of the battery pack or cell and an operating temperature T and for estimating the operating current I of the battery pack or cell. A plurality of time observation windows Wi is identified and characterization voltage Vmi values are detected. Then, at each observation window Wi, the following actions are performed: calculating a value of the state of charge SOCi of the battery pack or cell; calculating an estimated voltage VABi, by means of the model of the battery pack or cell, as a function of respective nominal values of the parameters P; determining a respective error function Ei dependent on the difference between the estimated voltage VABi and the characterization voltage Vmi of the time observation window Wi; calculating an actual value Pi for each parameter P, by minimizing the aforesaid error function Ei.