The Storm Battery's projectiles electrify their target for 9 seconds. Every time an electrified creep is damaged by an attack or spell it has a chance of 20% to take 40% extra damage.
The tower attacks creeps in a range of 1200 every 0.2 seconds till all mana is gone. Each attack (or try to attack) costs 10 mana, deals 300 spelldamage and electrifies the target.