Take a drained battery.If you charge it in a electrical battery charger,it will be filled with stored
energy.Stored energy can convert into other kinds of energy depening on where the energy needs
to go.If you hook a charged battery up to say a lightbulb or a motor,then all of the stored energy
will leave the battery then convert into another form of energy to be able to power up the motor or
the lightbulb...