This study interpreted open circuit impedance measurements of single negative and positive lead-acid battery plates. which were at different discharge levels and arranged in a four-electrode cell. This was performed in the framework of a proposed general model of charge/discharge reactions, morphological models of active materials, and based on interpretation of the characteristics of single negative and positive plates as measured by electrochemical impedance spectroscopy (EIS). This study shows that the proposed reaction models, morphological characteristics and EIS attributions are compatible with the obtained EIS data. The analysis indicates that negative and positive plate reaction mechanisms cannot be those proposed by the dissolution-precipitation mechanism alone. Rather, the reactions seem to obey the various mechanisms and morphologic ideas proposed in the present paper. It is shown that variations in the resistivity and dielectric constants of discharged films need to be studied in greater detail than film thicknesses to gain a better understanding of the processes. (C) 2008 Elsevier B.V. All rights reserved.