Abstract: A supply device comprising a tubular body configured to contain a battery pack formed by a plurality of cells organized in a predetermined number of layers. The supply device provides, furthermore, a control unit configured to monitor the state of functioning and to manage the state of charge of the battery pack and a connector comprising a plurality of electrical contacts to supply, or absorb, a predetermined electric power. The supply device provides, furthermore, connection cables for connecting the battery pack to the aforementioned plurality of electrical contacts of the connector to the control unit. The layer of cells comprises a first group of cells and at least a second group of cells between which a housing channel is defined configured to house, in use, the connection cables.