Truck Battery Cable

I had some starting issues with my truck recently.  After looking into it some I discovered that my battery cables weren’t in good shape.  My truck has a dual batteries and it seems the corrosion was so bad that one battery wasn’t contributing when starting.  I decided to make my own battery cable as opposed to buying one.  I believe the setup I used will result in a better cable than the stock one or replacement available.

Here’s the old cable off the truck.  Starting at the bottom black cover is the terminal for the driver’s side battery.  Next, is the terminal for the passenger’s side battery and the feed wire from the post on the solenoid which carries current from the alternator.  Continuing along the wire, there’s a bracket and then the end which connects to the starter.

Here’s a close up on one of the terminals.  As you can see, the insulation has become brittle with age and heat which has started to crack.  The wire has also grown fat in spots due to internal corrosion.  Also, the terminal is a little worse for wear.

Here’s a better look at the corrosion.  In the pic below, the red wire is brand new and the middle wire is an old wire that’s still in good shape.   On the left is a wire full of corrosion which causes the internal resistance of the wire to go up decreasing the current through it.

To start with I needed some new red 2/0 gauge wire for the positive.  I chose to go with welding lead wire which is more flexible and has a more durable insulation.  The negative wire on the truck looked good except near to the terminals.  Fortunately, there was enough slack on the negative cables to allow me to trim the bad sections off and reuse them.

For terminals I decided to go with so called “military style” terminals.  I like these terminals because the cables are attached via bolts allowing replacement of pieces if necessary.   I also ordered some lugs to attach to the wire to connect the pieces (not pictured).

The lugs I purchased need to be crimped on and to do that I picked up a cheap hydraulic crimper from Amazon.  You can tell it’s a cheap model but it worked well.  The crimper has different dies that can be used for different gauge wires which make it pretty versatile and useful for other projects.  You can solder on lugs as well but I think a good crimp gives a better connection.

I took measurements off the old cable and cut my new wire in to segments a little longer.  Next, I slipped on a piece of adhesive heat shrink tubing and removed the insulation from the end of the wire for the lug.

Then comes the fun part…crimping the lug.  You almost need three hands to do this part.  I found it easier to lightly squeeze the lug with the crimper and then insert the wire for the crimp.  Once you’re absolutely certain the wire is where you want it, start pumping.  After multiple pumps the lug and the wire have become one.  Then, for this lug, you move a bit down, and crimp it again.  Yup, that’s never coming off.  In retrospect, I may have overcrimped a bit but seems to have worked ok.

After crimping, I dabbed a little dielectric grease around the exposed wire and then sealed it with the heat shrink tubing.  This heat shrink tubing has an adhesive inside of it that oozes out around the ends to hopefully make a more durable seal.

After that was more crimping until finally I had two large cables and a small cable with lugs on the ends.  The lug for the starter has a 90 degree like the original cable.  The original cable had a rubber elbow molded onto it where it was held by a bracket.  To replace the elbow I used a piece of 3/4″ heater hose.  Later on, plastic wire looms were put on the cable similar to the stock one.

I crimped lugs on to the negative battery cables using the same process for the positive cables.  Now it’s time to install.  I attached all the terminals and put the cables into position.  After that all the wires were attached to the terminals.  In these pics I’m using the hardware that came with the terminals but soon after I switched over to nylock nuts to keep the nuts from loosening.

Above is the drives side battery and below is the passenger side battery.

I’d pulled the old starter off while I waited for all the supplies for the battery cable to arrive.  It looked worn and I decided to take a peak inside to check the condition.  One of the bearings was very stiff and one of the brush leads was partially broken.  There was also bit of scoring on the commutator and toasty electrical smell.  All this lead me to purchase a rebuilt one from the store.

With the new battery cable and starter in place the truck turns over and starts much quicker.  Startlingly so.  Clearly, things are working better.


I little bit afterwards, I ran across these battery terminal covers and picked them up.  I also converted the terminal nuts over to nylock nuts.  I had to trim the opening on the passenger’s side cover a bit to get all the wires to fit.

Should be good for a few more miles down the road!


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5 Responses to Truck Battery Cable

  1. Gill says:

    Great job David, enjoyed the write up and photography.

  2. P. Wiebe says:

    Another great project. It’s nice seeing how your projects turn out. Thank you for taking to time to post them. Always high quality work; both the project and post.

  3. jackywonders says:

    Hi. Can you give me any advice to improve my blog. Please visit my blog and follow me. Thank you. Have a nice day!

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