A group of rechargeable batteries held within a holder, container, or mobile cart/trolley intended to provide temporary electrical energy to operate a medical device, typically when it is not possible, intentional, or convenient to connect the device being powered to a mains electricity (AC-powered) electrical outlet; it might additionally have features to facilitate transport of the device being powered (e.g., push handles, storage shelves, mounting rails). It is typically used during a transport situation (e.g., a neonatal incubator) or to power a cordless device (e.g., an endoscopic device or a rechargeable battery-powered surgical drilling system handpiece). This is a reusable device.