This paper proposes a simple and efficient method to estimate the parameters of the photovoltaic (PV) cells at standard test conditions (STC). The proposed method is based on developing a mathematical model for each parameter of the single-diode equivalent circuit of the PV cell. The models are formulated using Eureqa software based on thousands of training data collected from simulating the equations that represent the equivalent circuit behavior of the PV cell. Only the data provided by the manufacturer's datasheet are needed to execute the models and evaluate the parameters. The performance of the developed models is then assessed by comparison with simulation data, Simulink library modules, experimental data, and various recent reported algorithms. The assessments have shown an overall efficient performance of the models to evaluate the equivalent circuit parameters for any poly and monocrystalline PV cell/module at STC. In addition, the models are in good agreement and, in some cases, have outperformed various algorithms presented in the literature in terms of the accuracy of predicting the I-V curve characteristics.