A reversibly connected battery pack is provided. The reversibly connected battery pack includes a pair of end frames, at least one frame, a plurality of battery cells, and at least one power connector. One end frame has a positive terminal, and the other has a negative terminal. The frame(s) is positioned between the pair of end frames. Each of the plurality of battery cells has a positive tab and a negative tab. The positive tab of one of the plurality of battery cells is electrically connected to the positive terminal in the end frame, and the negative tab of another one of the plurality of battery cells is electrically connected to the negative terminal in the end frame. The plurality of battery cells are positioned in the frame(s) and the end frames. The plurality of battery cells and the positive and negative tabs are supported by the frame and the pair of end frames. There is at least one power connector electrically connecting the negative tab of one battery cell with the positive tab of an adjacent battery cell.