Building Better Battery Cables - Kopycinski's BrainPosted in How To: Electrical on August 6, 2014
Custom vehicle work often requires custom parts, which can include electrical wiring and connectors. You may need to create custom battery cables or other heavy-duty wiring for a winch or other high-current accessory. Often, this is best done by creating battery cables to the length you require. You can purchase them from custom suppliers or can build your own.
Wires can be soldered, and we’ve done that before. However, soldering big wires requires a hefty heating element (or torch) and a lot of solder. Crimping is a faster alternative, and a quality crimp can offer a reliable connection both mechanically sound and highly conductive.
Here, we’ll show you the basics of using an inexpensive mechanical crimper to construct your own heavy battery cables. For connections to the battery, you can use screw-type connectors that come in a variety of types. Lug ends used to connect to threaded studs can be completed with the crimper.
We prefer to use welding cable for our high-current wiring needs. The welding cable uses a fine-stranded copper core that is very flexible and is far easier to route than standard large-strand battery cable. You can purchase large wire cutters designed for cutting heavy cables, but a big pair of diagonal cutters can get the job done as well. On the larger-gauge cables, you may have to nibble your way through the entire cross-section of copper with a few successive bites.
Lugs (or terminals) are available in bare copper or in tinned form. The tinned ones resist corrosion better. They should match the gauge wire you’re using and the size stud you’re bolting the lug to. Common auto power wire sizes range from #4 up to maybe 2/0. To determine size, you can use an old cable for reference or consult online charts that specify electrical current capacity.
For crimping, we’re using this Temco manual crimper we picked up for about $17. It will service 8 to 4/0 gauge wire. The crimping procedure is straightforward: Strip back the insulation to the proper depth using a utility knife. Place the battery cable in the lug and the lug in the crimper. Use a press, bench vise, or a couple of hammer hits on the crimper and the crimp is complete. The lug collapses onto the stranded wire until any free space is consumed and the crimping action ceases. It’s quick and simple to use. This is a good choice for a crimper if you only build battery cables occasionally.
Here’s a properly crimped lug using the manual crimper. The only thing left to finish this cable end is to apply heat-shrink tubing over the crimped portion of the lug. With these methods, you can create all your own high-quality custom-length battery cables economically.