Methods and systems for assembling customizable solderless cables for direct current (DC) transmission of electricity to an electronic device. The systems and methods utilize shielded co-axial cable defining first and second opposed ends which may be cut to a desired length as selected by the user. Connectors, which may have a conventional 2.1 mm×5.5 mm DC plug design, include a barrel portion defining a threaded axial passageway. In use, the threaded passageway of the plug is twisted upon a respective end of the cable such that the end of the cable becomes threadedly seated thereinto and in electrical contact with the plug to form two dedicated electrical connections. A respective other plug is mounted on the other respective end of the cable in the same manner to thus define the customizable cable. A single length of cable or a plurality of wire segments and plugs may be sold as a pre-packaged unit for use in making a plurality of customizable DC cables.