A major factor controlling the specific energy of a lead/acid battery is the utilization of active material. If this could be increased, the specific energy would be increased, with a corresponding increase in range of electric vehicles using the lead/acid battery. The main parameters that affect active-material utilization are examined, namely, current density, plate thickness, active-material structure, conductivity of active material and grid, and electrolyte volume and density. Increases in utilization can be achieved by changing all these parameters and examples are given.