Improved battery separators are disclosed herein for use in various lead acid batteries, and in particular lead acid battery strings. The improved separators, batteries, battery strings, methods, and vehicles disclosed herein provide substantially increased battery life, substantially reduced battery fail rate, and substantially higher voltage uniformity among the various batteries in a battery string. The improved battery strings may be advantageously employed in high depth of discharge applications such as electric bicycles, golf carts (or golf cars), uninterrupted power supply (UPS) backup power battery strings, and the like.