Method of Evaluating Remaining Power of a Battery for Portable

An apparatus comprising:

• an energy management circuitry of at least one battery having one or more specific parameters configured:
• to measure a momentary voltage and a momentary current of each of the at least one battery;
• to provide a corrected voltage U of each of the at least one battery based on the measured momentary voltage, the momentary current and the one or more specific parameters;
• and
• to provide an amount of available energy E in at least one of the at least one battery, each amount of available energy E being based on a function f1 of the corresponding corrected voltage U and the one or more specific parameters.

A method comprising:

• applying a set of low and constant power consumptions to a battery;
• measuring a first set of voltage drops of the battery respectively resulting from the set of low and constant power consumptions;
• applying a set of high power consumption to the battery;
• measuring a second set of voltage drops of the battery respectively resulting from the set of high power consumptions;
• and
• determining a parameter alpha specific to the battery by correlating the power consumption applied to the battery with the resulting voltage drops.

A computer-readable medium encoded with instruction that, when executed by a computer, perform:

• measuring a momentary voltage of a battery having one or more specific parameters;
• measuring a momentary current of the battery;
• providing a corrected voltage based on the measured momentary voltage and the momentary current and the one or more specific parameters;
• and
• providing an amount of available energy E in the battery based on a function f1 of the corrected voltage and the one or more specific parameters.