The electrical modeling of a proton exchange membrane electrolyzer (PEMELZ) to determine the voltage-current (V-I), the power current (P-I) characteristics and the electrolytic cell efficiency has been extensively reported in the literature. However, the dynamic cell performance, the possibility of overpotential, and the ohmic losses demand special attention. This paper proposes an electrical equivalent modeling of the PEMELZ where the dynamic cell performance can be evaluated by taking into account the fluctuations in the external current profile. The overpotential and the ohmic losses variations as the operating conditions, such as temperature and pressure, vary are also taken into account. The performance of the proposed model is compared with those of the reported models. The proposed electrical equivalent model can play an important role in analyzing PEMELZ, where the PEMELZ is supplied by a renewable resource, such as solar PV or wind, to produce and store the green hydrogen, and integrated with other electrical energy storage systems in a power grid.