Electrical Basics and Automotive Grounding Systems



Left: A good choice for a new ground system, Right: a not-so-good choice for a new ground system (Right photo courtesy of Nissan, left photo courtesy of me.)

There’s good news, though.  You don’t have to pay a ton of money for a ground system.  (HKS’s system is over $100, for instance.)  All you need to do is get some car audio power cable and some ring terminals.  The brand I chose is Stinger.  Depending on the size of your engine bay and how many different points you need to ground, you’ll need somewhere between 15 and 30 feet of cable.  I used 4-gauge cable.  

stinger wire ring terminals
Stinger wire and ring terminals.  (Photos from StingerElectronics.com)

Most of the grounding kits you see on the market connect every ground point in the engine bay directly back to the negative battery cable.  This is done because those kits use relatively small wire, usually around 14-gauge.  Since we’re using 4-gauge, we don’t have to directly connect everything.  Instead, daisy-chaining different grounding points together will be more than sufficient and will also cut down on clutter.

The first step of your grounding kit is connecting an additional ground wire between the negative battery terminal and the chassis.  Try to keep this wire as short as possible, as this one will be carrying the most current.  Any current in your vehicle will eventually be carried on this wire when it returns to the battery.  Cut the wire to the proper length using some beefy wire cutters and attach the ring terminal to both ends.  Put one ring terminal on the negative battery terminal and the other one on the factory chassis ground point, leaving the stock wire intact.

Here’s a picture of my negative battery terminal.  Yes, it’s old and beat up.  The supplemental ground wire I installed is the black one at the bottom of the picture.

Speaking of battery terminals, old battery terminals get dirty and corroded, adding even more resistance into your automotive circuitry.  You may wish to replace them.  I purchased two aftermarket battery terminals made for car audio competitions.  The nice thing about them is that you can simply cut the old terminal off and tighten the wires into the new terminal.

1 comment

  1. Very good read. I would just add a word of caution when tieing Electrical Ground to Signal Ground especially in newer vehicles with more onboard electronics. The Electrical Ground provides the voltage differential to insure things like Spark Plugs work well. However, spark plugs (and wires) also generate lots of signal noise that electronics do not fair well with.

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