Storage Batteries

Large amounts of energy can be stored in electric storage batteries. Consider a 6-v battery rated 100 amp-hr. If the drop in voltage is neglected as the battery gives up its charge, the energy given up by the battery is 600 whr. This amounts to 600 x 3600 = 2.18 x 10⁶ j or the equivalent of about 14 percent of the energy stored in a pound of coal.