Geoff: While it is strictly true that battery means more than one battery, in the real world more than one is two and two is a pair. Hence a pair of battery is actually two batteries. Do you feel better now? But your posting brings to mind a much more serious linguistic offence, namely, the battery upon the word "assault". Strictly speaking, an "assault" is an attempt to commit a "battery", or the threat of a "battery", not a "battery" itself.