State of charge estimation based on battery discharge model

It is proposed a method for estimating a charge level for a battery comprising the step of using a coulomb counter for estimating the State of Charge of the battery at a given time on the basis of the consumed charge Q i measured until this given time and on the maximum charge Q max of said battery, wherein the maximum charge is given by: Q max = 60 T max i load , Wherein T max =60.[(Q i /i load ) + (K.Q i /)] and =V cut-off -E 0 +R.i load , and wherein i load is the measured load current flowing through the battery, V cut-off is the cut-off voltage of said battery, R is the internal resistance of the battery, E 0 is a base voltage of the battery and K is a coefficient of the battery.