This brief note presents a reduced-form of the five-parameter model introduced by Desoto et al. (2006) and subsequently generalized by Tian et al. (2012). The five-parameter model computes five reference parameters utilized to synthesize performance curves in photovoltaic panels from information available in datasheets. The improvement resulting from the reduced-form is twofold: (i) the model is reduced from five to two parameters and (ii) as a result of (i) a domain of attraction of the solution space is defined analytically, which guarantees nonlinear solvers will provide the correct, that is, physically feasible, solution for the parameters at first launch. (C) 2013 Elsevier Ltd. All rights reserved.