Abstract: A method for estimating a capacity of an electrical energy storage device with higher accuracy than what is provided in the prior art. The uncertainties in measured electrical current or voltage used in the estimation of the capacity of the electrical energy storage device are at least partly compensated for by using a bias compensated capacity estimator instead of the often-used prior art capacity estimator. The accuracy of the voltage and/or electric current sensor becomes of less importance which leads to that less complicated and less costly sensors may be used and to improve accuracy of the estimated energy storage capacity. The above advantages are obtained by providing a bias compensated capacity estimator that includes at least one bias term which is related to a deviation of an expected value of an original capacity estimator from a true capacity value.

Abstract: A method for estimating a capacity of an electrical energy storage device with higher accuracy than what is provided in the prior art. The uncertainties in measured electrical current or voltage used in the estimation of the capacity of the electrical energy storage device are at least partly compensated for by using a bias compensated capacity estimator instead of the often-used prior art capacity estimator. The accuracy of the voltage and/or electric current sensor becomes of less importance which leads to that less complicated and less costly sensors may be used and to improve accuracy of the estimated energy storage capacity. The above advantages are obtained by providing a bias compensated capacity estimator that includes at least one bias term which is related to a deviation of an expected value of an original capacity estimator from a true capacity value.