For some reason when I started out in electrics I ordered 2 two cell (7.4 volts) 2000mah packs. Why I ordered them I have no idea, but I have them and I don't want them to just collect dust. Now some of the motors I have will run on 4 cells. Can I take a red lead from one and connect it to a black lead from the other and use the other red and black as the batt connector to get a 4S pack? Basically connecting them in series without taking them apart and soldering them together in one pack?