Abstract: A charging system includes a primary single charging bay unit and at least one secondary single charging bay unit. Each of the units has an adapter cup for receiving one of a battery and a battery-powered device for charging, an associated printed circuit board disposed beneath the adapter cup, and a primary printed circuit board disposed within the main body. The least one secondary single charging bay unit is in communication with the primary single charging bay unit via a user assembled backplane bus. The backplane bus is expandable to permit a gangable or build-out configuration of the charging system.