Solid polymer electrolyte films of polyvinylpyrrolidone (PVP), and poly(vinyl alcohol) (PVA) with KClO3 and KClO3 + plasticizer (dimethyl formamide) have been prepared by the solution - cast technique. Various experimental techniques such as electrical conductivity (composition dependence) at room temperature and transport number measurements are used to characterize these polymer electrolyte films. Electrochemical cells of configuration K\(PVP + PVA + KClO3)\(I-2 + C + electrolyte) and K\(PVP + PVA + KClO3 + plasticizer)\ (I-2 + C + electrolyte) have been fabricated. The discharge characteristics of the cells are studied under a constant load of 100 kOmega. The open-circuit voltage, short-circuit current and discharge time for the plateau region are measured. The PVP + PVA + KClO3 blend polymer electrolyte system with added plasticizer shows an increased discharge time with respect to the pure PVP + PVA + KClO3 blend polymer electrolyte system.