This paper develops and evaluates an elementary electrical circuit model for a storage cell. The model is applied to both lead-acid and nickel-cadmium cells. It exhibits the appropriate terminal voltage, current behavior and, for lead-acid batteries, the observed nonreciprocal power-energy relationship. The circuit model provides an accurate simulation of electric vehicle propulsion batteries, enabling vehicle designers to make good preliminary evaluations of driving range under a variety of conditions, including urban driving cycles. Also described is a programmable battery test stand which can simulate an electric vehicle under these same conditions and provide direct measurements of battery capacity.