Upgrade Your Battery Cables

Electrical problems have punctuated the winter this year with the Big White Bus. I’ve had a lot of trouble electrically speaking. The engine has run rough for a few months now. The tachometer has been exhibiting the bouncing needle problem indicative of a failing alternator. A glowing battery charge light when the headlights are on. And of course as you read in the last post my ignition switch has been acting up.

I got the ignition switch problem sorted out and now it was time to upgrade the battery cables. And there is only one man you go to when it comes to electricity, The Evil German Dude. His evil liar has all the tools and he has a supreme understanding of the dark art of electricity.

Other than “replace the cables” there really wasn’t a clear and concise plan when we started to swap the original OEM battery cables for an upgraded set hand-crafted by the Evil German Dude. The plan is pretty simple:

  • Remove the old cables.
  • Build new comparable cables.
  • Install the new cables.

There are four battery cables of concern on this project. One goes from the positive battery post to the starter. One goes from the positive battery post to the alternator. One goes from the negative battery post to the frame. And the last is a fresh ground connection to the fender from the negative battery post.

We also upgraded the battery post connections to industrial grade. The ones they sell at the auto parts store are just…INADEQUATE.

EGD was able to salvage some heavy-duty battery cables from a private contact he has and we re-purposed them for use on the Range Rover.

The battery has been removed. The old cables are still in place.


Here I am removing the old connector from the alternator to the starter. We replaced it with one run directly to the battery. I asked EGD why he thought they ran it to the starter instead of the battery. He thought it was a manufacturing thing. So to save the trouble we ran the cable directly to the positive post.


You will need to remove the cables from the starter. The new beefier battery cable needed only a little grinding on one side to fit the post.

EGD removes the insulation from the fender ground cable.

The ground cables are bundled and getting ready for crimping into the battery terminal. The shrink-wrap is in place and the zip tie is to hold every thing in place while it is crimped.

The cables are bundled and ready for crimping.

We hold the jigs in place as we close the crimping tool. We wanted it to be aligned correctly so the crimp tool crimped evenly and we got the results we desired.

You can see the crimp tool in use here.

EGD wields the heat gun to activate the shrink-wrap. To further seal it we applied hot glue to the bare wires that were outside the battery terminal.

This is the positive battery cable. All the cables got the same treatment. Hot glue to seal (or attempt to seal) and then heat shrink. The goal is to keep as much atmosphere off them as possible.

I used a file to scratch a bare spot on the fender. I bolted the connector down and then covered everything in dielectric grease. I know it won’t matter after the first hot summer day but it looks good now. Bring on the rust.

With all the cables made all that is left is to run all the cables and hook them up. It is important to secure them. We used the original bolts and straps where we could. Zip ties took care of the rest.

I rolled under the Range Rover and hooked up the new cables. This reminded me one of my next projects is to slow the oil leaking from the various gaskets. The oil pan gasket must be mostly perforated as there is a lot of oil under there. I will also invest a set of ramps. I will take them with me to the car wash when I go to remove the layers before replacing the gaskets.

Let us have a word about “Original Equipment”. I don’t know why one of my friends took this picture but it reminds me that sometimes we need to modify our Land Rovers. In the case of this project we needed to upgrade the wiring that charges the battery and delivers the power to the circuits.

The stock wires provided are within tolerances, proper to the design specifications, in a word they are “adequate”. But when you install a new sound system OR upgrade your headlamps OR add auxiliary lights the stock battery cables are not going to cut it any longer. We upgraded the cables to 2 gauge. The OEM cables are most likely 10 gauge.

The gauge is important due to the current you are trying to run down the wire. This is a lovely chart from Crutchfield.com

The battery cables on the Range Rover are in the four-foot length range. So you can see that the gauge of wire to run 30 amps (think about the 30 amp fuses) is important. When you feel a wire getting hot you know you are running more current through it than it was designed to have. Yet another reason not to buy cheap jumper cables.

Hopefully all this makes sense and helps you see the importance of proper cables. With the new battery cables my alternator now charges the battery properly. The discharge indicator lamp on the dash no longer glows when I turn on my headlights. The tachometer no longer bounces when I get the RPMs up past 1500. The Range Rover is running better than it has in a long time. In short, my charging system was seriously tasked and now it is not.

Thank you to my friends who helped me. Magnum Mike, Paparazzi Ford, and the Evil German Dude. I love the camaraderie and it was just what I needed this month.

Thanks for reading and Happy Rovering.

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