A lead acid battery is provided. The battery includes a container and a plurality of electrochemical cells within the container. The electrochemical cells have a plurality of flat positive plates eachcomposed of a grid formed of virgin lead or high purity lead or highly purified secondary lead and a positive battery paste disposed on the grid, the battery paste comprising a lead-containing composition, a positive plate paste vehicle, and a polyvinylsulfonate additive. The electrochemical cells also have a plurality of flat negative plates each composed of a grid and a negative battery paste disposed on the grid, the battery paste comprising a lead-containing composition and a negative plate paste vehicle. An absorbent glass mat is interleaved between the flat positive plate and the flat negative plate. An electrolyte is provided in the container and retained in the absorbent glass mat. The electrolyte includes phosphoric acid. The plurality of flat positive plates and the plurality offlat negative plates are connected by intercell connectors and coupled to one or more terminals. A lid is provided on the container.