A system for charging a battery is provided. The system includes a first and a second container, each including receptacles shaped to receive a battery and protrusions each being aligned with a receptacle, wherein a number of receptacles and protrusions in the first container is greater than a number of receptacles and protrusions in the second container. The system also includes a charging device including charging bays each being shaped to receive a protrusion. The charging bays are arranged in rows and columns with a number of columns corresponding to a number of receptacles in the first container and a number of rows corresponding to a number of receptacles in the second container. Each of the charging bays comprises an antenna configured to provide charging power to a battery disposed in a receptacle. The charging device includes a charging controller to provide charging power to the battery via the antenna.