This presentation continues the study of the dynamic characteristics of lead-acid batteries previously reported into larger cells and batteries. Electrochemical impedance spectroscopy combined with fuzzy logic methodology of data analysis was used to characterize 6 V 10 Ah VRLA batteries and larger batteries used in tanks and other vehicles. Equivalent circuits were derived which can be used to estimate state-of-charge (SOC) and state-of-health. (C) 2003 Elsevier Science B.V. All rights reserved.