Realistic electric vehicle battery evaluation

The STM-5-140 nickel cadmium electric vehicle battery was tested under actual operating conditions using the UMASS Lowell battery evaluation laboratory. The battery evaluation system uses battery current data taken from an EV using its on board data acquisition system. The car is driven on a typical commute while battery current as well as other data are taken at one second intervals. In the battery evaluation lab, individual batteries are subjected to the same operating conditions as those in the car. This procedure uses fewer batteries and allows the same commute to be repeated exactly. Three test procedures using 0, 20, and 40 degree centigrade controlled environment temperatures were implemented. Measured data consisted of voltage, current, and temperature. Test cycle, capacity and round trip efficiency data are presented.