Novel adaptive method for the estimation of the electromotive force of the battery -The proposed concept offers an accurate state-of-charge and capacity estimation -Analysis and implementation of novel least squares estimation schemes -Use of a-priori information about the battery for the extrapolation process -Evaluation of the proposed concept based on an implementation on a system-on-chip M Abstract In recent years, much effort has been spent to extend the runtime of batterypowered electronic applications. In order to improve the utilization of the available cell capacity, high precision estimation approaches for batteryspecific parameters are needed. In this work, an approximate least squares estimation scheme is proposed for the estimation of the battery state-of-charge (SoC). The SoC is determined based on the prediction of the battery's electromotive force. The proposed approach allows for an improved re-initialization of the Coulomb counting (CC) based SoC estimation method. Experimental results for an implementation of the estimation scheme on a fuel gauge system on chip are illustrated. Implementation details and design guidelines are presented. The performance of the presented concept is evaluated for realistic operating conditions (temperature effects, aging, standby current, etc.). For the considered test case of a GSM/UMTS load current pattern of a mobile phone, the proposed method is able to re-initialize the CC-method