Dynamic performance of a 10-kW proton exchange membrane fuel cell (PEMFC)–battery hybrid system to power servers in data centers has been experimentally evaluated in our previous work [1]. The present work is a numerical study based on the previous work to identify the dynamic characteristics and present basic insights for the system control strategy during transients. The hybrid system dynamic model has been developed using the MATLAB–Simulink®, which consists of a one-dimensional, two-phase dynamic model of the PEMFC, lumped dynamic model of an air blower and a battery. The system model is verified by comparing the dynamic behavior of the power generated by the PEMFC and battery with the experimental data at the step change of the system demand power between 0 and 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 kW. During the step load increases, the system instantly obtained the total amount of external load power from the battery within 0.1 s in every case and gradually decreased until approximately 4 s or 6 s as the power generated by the fuel cell is gradually increased. The dynamic response of the system model is compared with the experimental data at various load profiles of three, six, and nine servers.