A predictive model of the reliabilities and the distributions of the acid concentrations, open-circuit voltages and capacities of valve-regulated lead/acid batteries during storage

A model is presented which can be used to determine the distribution of voltages, acid concentrations and capacities of stored, valve-regulated (or sealed) lead/acid (VRLA) batteries with absorptive glass mats (AGM). Data taken on the self-discharge of six-cell, flat plate batteries are used to test the model. The actual capacities of cells stored at room temperature for up to two years correlate closely with capacities predicted by the model from measured open-circuit voltages. The model may also be used to predict capacities and voltages of cells stored at any temperature from data taken at only three temperatures.