When wiring up an electric vehicle traction pack battery, an off-grid battery backup bank, or other high current power systems, you sometimes need a cable capable of handling high-current with a custom length. If you have a few tools, it is easy to make your own by crimping terminals onto welding cable. This video shows a time-lapse overview of making such a cable:
Here is a set of links to the tools and materials I used:
- TEMCo Hydraulic Cable Lug Crimper TH0006 – 5 US TON 12 AWG to 00 (2/0) (to crimp the lugs)
- Razer knife (to cut the insulation)
- TEMCo Welding Lead 20′ Black/Red (10′ Blk, 10′ Red) 2/0 Gauge AWG cable
- 2/0 AWG Ring 5/16″ Hole Terminal Lug Tin Plated Copper (purchase a lug size and ring size to match your cable and terminals)
- QUICK CABLE 5724-360-005R Terminal Protector, Plug-In, PVC (from ZoroTools on Ebay)
- Heavy Wall Adhesive Lined Marine Grade Heat Polyolefin Shrink Tubing 1″ ID – Black
With the exception of the Hydraulic crimper, most of these parts are relatively inexpensive (or at least, as inexpensive as heavy copper wire can be…). You could substitute a hammer crimper to save a few bucks, but seeing as how the hydraulic crimper is only $80 and it works a lot more reliably without any real skill involved it is worth the extra $40-60.
The steps are relatively easy. First, make sure you know the exact distance you need between your terminals. Add a few extra inches just in case unless having slack cable would be a problem. Cut your wire taking into account the distance the ring terminal is from the end of the cable in the lug. Strip enough insulation that the lug will fully fit onto the copper with a small gap to the remaining insulation.
Hold the lug in place while you tighten up the crimper so that it doesn’t slip off the cable. After the lug is in place, seal the lug/cable with adhesive lined shrink tubing.
For the other end, I recommend placing the heat shrink tubing and terminal protector onto the wire BEFORE crimping the lug, just in case the head of your lug is too large to allow them to slip over it. (I didn’t have a problem with that in the video above, but it’s always better to have the heat shrink tubing and terminal protector on the wire before you permanently attach the lug.)
If you want to verify that your crimper is doing a good job, you can make a test crimp and then cut it in half with a metal cutting saw. It should look like a solid piece of copper inside the lug.
Pay attention to the orientation of the lugs. If you are dealing with golf cart batteries, which all have their terminals on the top facing the same direction, you probably want the lugs all “flat” so that cables don’t twist. However, in some situations you want the lugs to be 90 degrees “out of phase” with each other so that the cable twists correctly. The easiest thing to do here is to put the cable in place with at least one lug loose, and mark a line with sharpie showing how the lug should be oriented. (Note how I have all of the terminal covers and heat shrink tubing on the cable before crimping the lugs.)