A battery washing machine for automotive type vehicle batteries, comprising an enclosed wash cabinet with an overhead spray apparatus, drain racks for supporting the batteries below the spray apparatus, and a water tank beneath the drain racks. The water tank is divided into separator and recirculating supply portions by a vertical separator wall that is partly screened and partly solid. The upper end of the separator portion of the tank is covered with a screen, while the upper end of the recirculating supply portion is covered with a solid water-diverting panel. Solid contaminants are screened and/or settled out of the re-circulated wash water in the tank by the vertical separator wall.