Abstract
A lead‐acid battery stored in an acid‐starved condition, rather than in a totally flooded state, shows a well‐behaved and predictable decline in open‐circuit voltage with time. The voltage‐time curves of such batteries can be used to determine the rates of the predominant self‐discharge reactions and to study the reaction mechanisms. An abrupt change in the slope of the curve indicates a change in the dominant self‐discharge process. Acid‐starved automotive (SLI) batteries with antimonial‐lead grids show a slope change at 1.85 V/cell. This apparently corresponds to a change in the grid corrosion mechanism. Measurements of gas evolution from these SLI batteries show that the rate of hydrogen evolution is dependent on the acid concentration whereas the rate of evolution of carbon dioxide is independent of acid concentration. Oxygen reacts rapidly at the negative plate.