A battery pack (20A4), comprising: a housing having an interior cavity, the housing including an interface for coupling with an electrical device; at least one switch, the at least one switch being configurable between a first state and a second state; a set of battery cells housed in the interior cavity of the housing, the set of battery cells including a first subset of battery cells and a second subset of battery cells, wherein when the at least one switch is in the first state the first subset of battery cells is connected to the second subset of battery cells in series and when the at least one switch is in the second state the first subset of battery cells is connected to the second subset of battery cells in parallel, and characterized by : a converter element housed in the interior cavity of the housing, the converter element being movable between a first position and a second position and including a projection extending from the converter element, wherein the at least one switch is in the first state when the converter element is in the first position and is in the second state when the converter element is in the second position, and wherein the converter element projection is positioned to receive a mechanical input from the electrical device to move the converter element from the first position to the second position. a housing having an interior cavity, the housing including an interface for coupling with an electrical device; at least one switch, the at least one switch being configurable between a first state and a second state; a set of battery cells housed in the interior cavity of the housing, the set of battery cells including a first subset of battery cells and a second subset of battery cells, wherein when the at least one switch is in the first state the first subset of battery cells is connected to the second subset of battery cells in series and when the at least one switch is in the second state the first subset of battery cells is connected to the second subset of battery cells in parallel, and characterized by : a converter element housed in the interior cavity of the housing, the converter element being movable between a first position and a second position and including a projection extending from the converter element, wherein the at least one switch is in the first state when the converter element is in the first position and is in the second state when the converter element is in the second position, and wherein the converter element projection is positioned to receive a mechanical input from the electrical device to move the converter element from the first position to the second position. a converter element housed in the interior cavity of the housing, the converter element being movable between a first position and a second position and including a projection extending from the converter element, wherein the at least one switch is in the first state when the converter element is in the first position and is in the second state when the converter element is in the second position, and wherein the converter element projection is positioned to receive a mechanical input from the electrical device to move the converter element from the first position to the second position. <EOS>