Standard Amersil calendered ribbed separators based on the cold extrusion of PVC and silica have successfully been used in industrial lead acid batteries for over 30 years. The requirements of the battery industry for even more efficient separator systems have led Amersil to develop a new generation of highly porous polymeric material, well suited for traction as well as for stationary applications, both in flooded and gel VRLA technologies. The new polymeric separators are based on the unique Amersil production process and use the same raw materials of high chemical purity as the standard product, but the design has been optimised in order to improve the physical properties required to reach higher battery efficiency. Especially, the pore volume has been increased, the electrical resistance and acid displacement reduced to such an extent that the electrical output of batteries has been improved both in terms of higher capacity and longer cycle life. This paper shows the beneficial impact of the new Amersil separators on various types of industrial lead acid batteries.