A battery charging apparatus includes a battery charger having a housing and a battery mount plate for charging the battery. A contact block of the battery mount plate includes an electrical terminal configured to provide a charging voltage to the battery. The battery can operate in a first state in which the battery delivers a first delivery voltage or in a second state in which the battery delivers a second and higher delivery voltage. The battery can be charged in the first state or the second state. The battery charger switches the battery between the first state and the second state in which power is provided to the battery through the electrical terminal at the second and higher charging voltage to charge the battery.