A charging system is provided for use with the battery pack of an electric vehicle, where both the charge level and the charging rate may be specified over a range of available levels and rates, respectively. A system controller coupled to the charging system determines the optimal charging level and the optimal charging rate, where optimization is based on maximizing battery lifetime while insuring that there is sufficient power for the vehicle to travel the user's intended distance and that the charging process will be completed prior to the user's intended departure time.