Abstract The accurate electrical modeling of photovoltaic (PV) module is vital due to the extensive installation of photovoltaic power plants. Therefore, the scientists suggested a three-diode photovoltaic (TDPV) model for precise modeling of PV losses. However, TDPV is a complex and nonlinear model that contains nine unknown parameters. Hence, this paper presents a new method that is combining the computation and Harris Hawk Optimization (HHO) algorithm to extract the unknown parameters of the TDPV model. Also, this paper exhibits a new objective function based on the datasheet values instead of using extensive experiments for PV modeling for time-saving. The industrialists provided the datasheet values of PV modules at standard test conditions (STC) and normal operating cell temperature (NOCT). Therefore, this paper utilized these data to compute four parameters using equations and identify the remaining five parameters using the HHO algorithm. In this paper, the offered method is employed to find the TDPV model of two commercial PV panels, such as multi-crystal KC200GT and monocrystalline CS6K280M. After that, the I–V and P–V curves of these TDPV models plotted and compared with the curves of the measured data under different temperatures and solar irradiations. Moreover, the absolute current error of the proposed method compared with that obtained by using other methods. Accordingly, the results revealed that the proposed method is efficient and can be easily applied to identify the electrical parameters of any commercial PV panel based on the datasheet values only.