Due to recent oil price crisis and an ever-increasing public awareness on environmental issues, an interest in electric vehicles (EV) has increased tremendously in Thailand and other Asian countries over the last few years. In this study, a prototype of 9-metre battery electric vehicle (BEV) bus was chosen as a vehicle of interest to undergo a series of field test by operating the lead acid battery powered electric bus in order to estimate a power demand of the bus as well as to evaluate a battery performance characteristic Two different types of battery were employed in this study i.e. a flooded-type deep cycle lead acid battery and a valve regulated lead acid (VRLA) battery. The effect of different driving modes available from the drive motor i.e. normal, max power, max range, as well as regenerative braking feature would be investigated while an influence of drivers were also taken into account to ensure the repeatability of the obtained results. According to the field test results, the different electrical characteristics of each battery type and driving conditions directly affected the performance of the electric bus in aspect of power demand, range per charge. Moreover, the regenerative braking feature was found to improve the overall operating distance of the bus as well as providing an extra deceleration over the mechanical brakes. The results from this study would then be used to determine the most appropriated driving parameters, including charging routines, for application of the EV bus as an university campus fleet in the next phase of the ongoing project.