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HomeTips & GuidesBattery Cables for Cars – All You Need to Know

Battery Cables for Cars – All You Need to Know

About Battery Cables for Cars: Before you can even start driving, your car’s components must be in place and perfect condition. 

Some of these parts are the cables that transmit power from the battery to various components, e.g., the starter. 

We must discuss car battery cables, their standards and gauges, and how to choose them.

What Is a Battery Cable?

You may be familiar with the fact that the car battery makes the circuit system, starters, and ignitors work. 

You may not know the car battery cannot connect with these components using any wire. 

They require a heavy gauge conductor with a single core called the battery cable. It features a pure construction for proper conductivity and longevity.

 Its insulation is also the robust XLPE or PVC to prevent destruction from acids, fuel, water, and salts. 

In addition, it is flame redundant to withstand moderate heat. Generally, the cable comes with two terminals, which include the positive and the negative. 

The auto battery cables can also be used in marines and other industrial uses.

What Gauge and Standard Are Battery Cables?

These cables’ generally accepted standard gauge is 6 gauge for the 12V car battery. However, they can withstand up to 60V current, although 12V is the ideal.  Again, they have an operating temperature between -40 to 125 degrees Celsius to prevent condensing and melting. Additionally, they can withstand various engine fluids, as mentioned above. Note that these cables appear in different sizes and three main types, as bulleted below:

  • SGT Wire, which comes with PVC insulation for application in heavy-duty automotive current supply
  • SGW, which features XLPE insulation to withstand high temperatures under the bonnet
  • STX cable also comes with XLPE insulation, but it’s a bit rigid and withstands high temperatures in modern cars.

Battery cables separately 

Battery cables separately 

Factors to Consider When Choosing Battery Cables

According to our discussion, we can all agree that not all cables can act as automotive battery cables. 

The good thing is that battery cables have almost the same rating in terms of gauge. 

What now is remaining is to choose the best from the available lot using the considerations below:

Current rating

Typically, you will have many components drawing current from your battery. For this reason, you require a battery cable that serves all these devices without voltage drop.

 Your chosen cable’s current rating should equal the total current of your devices. 

For example, if you have one device with 10 amps and another with 20, your cable should be 30 amps and above. 

If your devices are rated in watts, divide the inscribed watts by your battery voltage. 

For instance, if you have a 120-watt device, divide that by your 12-volt battery to get 10 amps. Note that any drop can be significant since the battery is just 12 volts.


By size here, I am referring to the length and the thickness. The cable should be long enough to reach your components from the battery. 

It should also be thick, gauge 6, to withstand heavy current transportation. However, if it’s very long or very thick, it will cause current resistance. 

Consequently, you will get voltage drops and heating, which can spell problems in your ride.


Sometimes, the cable must pass through twists and bends in your vehicle conduits. If this is the case, avoid rigid cables and get a flexible cable that you can twist easily. 

Such a wire ensures fast and convenient installation without breaking sweat or destroying your cable.


While cost is also a consideration, check the required use first. For example, powering devices at the back of your RV while the battery is in front needs a long cable.

 The longer the cable, the costlier it is. While here, remember that the gauge and the insulation quality determine the final price. 

However, I recommend a robust cable, especially for durability, efficiency, and safety, even if it’s expensive.

How to Test the Battery Cables

As we said earlier, two cables exist for each battery. One is the positive battery cable that connects to the positive battery terminal to the ignition. 

The other one is the negative one, connecting the negative terminal with the grounding. 

Now, if any of these cables suffer damage, the engine won’t start or will be a sluggish start. 

In case you experience this problem, the first thing is to inspect it physically.

 Check for corrosion, damage, cuts, and bends, and if any, replace the cable.

Voltage drop test

At some points, you may not see the damage or corrosion physically. In such instances, you need to do a voltage drop test.

 It involves inspecting invisible damages that cause current flow drop to the starting circuit. 

Here, we learn how to do that, but first, use a digital multimeter to check if the battery has a full charge.

 Note that a full charge of a 12V battery must be about 12.2 volts. Just wear your safety glasses and set the digital multimeter to 20 volts. 

If all is ok and the battery is full, now perform a voltage drop test on the cables using the formula below:

  • First, configure the digital multimeter to 2 volts DC settings
  • Then, disconnect the ignition system to prevent your car from starting. You usually remove the fuse, injection relay, or disconnect ignition coil connectors.
  • Now connect the black meter terminal to the starter battery terminal and the red one to the battery positive.
  • Have another person ignite the car and note the reading, which should be 0.2 volts or less. If more than this, the cable is faulty and needs replacement. You can also do the same to the other cable.

Using a digital multimeter 

Using a digital multimeter 

How to Replace Battery Cables

Despite their heavy-duty copper construction, like all things, battery cables get worn out too, at some point.

 The good thing is replacing them is something you can do by yourself without requiring a mechanic. 

You just need to test the damaged one using the above method and replace it using the below steps. 

But before then, get a jack and jack stand, repair manual, safety glasses, wrench set, and wheel chocks. 

Now, if you are set with your glasses on, let’s start with the battery cable removal procedure:

  • For starters, gently raise your car using the jack and support it with the jack stands. Remember to chock the back wheels and set the parking brakes.
  • Now disconnect the negative cable and isolate it to prevent reconnection
  • Disconnect the positive cable and unscrew the fastener that secures the battery hold-down.
  • Then, remove the hold-down device and remove the battery from its position.
  • Lastly, trace the battery cables and loosen their connectors to remove them from the system.

After removing the cables, the next procedure is to install the new cables:

  • To start the process, first, inspect if the cables look like the ones you removed. For universal cables, you may need to trim or change connectors.
  • Now insect the vehicle battery connection points and battery terminals to remove any rust and corrosion
  • Then, put the cables in their place, faster them the way the old ones were, and then put the battery in its position.
  • Secure it with the hold-down and then connect both terminals in their place.
  • Lastly, remove the jack safely and test if everything works by starting the car.

Disconnecting battery cables

Disconnecting battery cables

Recommendations for Upgrading and Maintaining Car Battery Cables

Universal Cables

You may need a universal cable kit to upgrade your battery cable to a custom appearance. 

But as we said, the universal cable may require trimming and changing the connector. 

Also, ensure they are of the correct gauge and quality.

Cleaning Tools

To prevent battery failure and voltage drop, you need to have quality cleaning tools.

 These remove rust and corrosion from the battery terminal, thus prolonging its life.

Battery Terminal Replacement

Another way to care for your battery involves replacing its terminal with a quality one. 

Remember, a bad or worn-out terminal can cause voltage loss, affecting your car’s electrical supply.

Wrap Up

Now you have all the information about batter cables and how to test their integrity and replace them. 

What remains now is to put the information into action and eliminate the slow start in your vehicle.

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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