How To Tell Which Is Positive and Negative on Car Battery?

The battery is the car’s main powerhouse, and knowing how to tell the positive and negative terminal on the battery is crucial for the safety and longevity of the vehicle and battery. Supposedly, your battery dies, and you need to jumpstart it or change an old battery for a new one: knowing the difference between the terminals can be a lifesaver. Read on to tell the positive and negative terminal on a car battery.

Ways to tell the positive and negative on car battery

There are a few different ways to differentiate the terminals, some more popular than others. Highlighted below are the ways you can successfully tell the difference

  • Printed Signs visible near the terminals: most batteries have printed signs + and – signs near the terminals to differentiate them. If a terminal has the + sign, it is the positive terminal, and the one with the – sign is the negative one.
  • Colored plastic cover and wiring: another way to tell the difference is by looking at the terminal covering or wiring. The positive terminal always has a red cap or wire, while the negative terminal has black. If the terminals both have the same-colored covers, use the signs to differentiate.
  • Diameter of the battery terminals: Examine the batteries and look at the metals on each terminal. The positive terminal is slightly larger or more prominent than the negative terminal. 
  • Usage of a voltmeter: lastly, a voltmeter can help get the battery polarity. The terminal with the highest voltage is usually the positive terminal, while the one with the nominal voltage is the negative one.
jump starting a car battery

How to replace a car battery. 

Knowing the difference between the battery terminals is essential, but knowing how to connect them properly is more important as it can prevent battery damage. There is a simple way to replace a car battery, and it is highlighted below:

  • Locate the battery: look to see if the battery is under the car hood. The new model cars have a cover on the battery that can be lifted to see the terminals. If you open the hood and can’t see the battery, consult the car manual for the location.
  • Identify the battery terminals: After finding the battery, find the positive and negative terminals of the battery. Most batteries use color and signs to differentiate the terminal. However, if the terminals are not distinguished, the manual should detail how to go about it.
  • Detach the negative terminal first: you must disconnect the negative terminal connector first. Removing the positive terminal connector can cause an electrical shortage. Instead, remove the negative terminal connector first by loosening it and shaking it off till it is free. Do this for the positive terminal too.
  • Connect the new battery positive terminal: After you are done with the battery and place it back, reconnect the positive terminal first and the negative terminal after. When putting the battery back, the positive terminal always comes first. Also, be sure not to touch any metal part of the car during this process, or it may spark. Cover the battery and close the hood, and it should not cause any issues if done correctly.

How to jumpstart a car battery 

Jumpstarting a dead battery can cause damage to you and the car if it is not done right. Knowing the difference between the battery terminals can help prevent damage to the battery. The ways to jumpstart the car battery are listed below:

  • Wear a safety gear 
  • Attach the red cable to the positive terminals of the dead and the good battery. Also, attach the black cable to the negative terminal of the good battery and connect the other end of the black cable to a ground location on the vehicle of the dead battery. Good ground location includes bare metal part of the engine or body of the car.
  • Check if the connections are secure and start the car with a good battery. increase the engine speed to about 1500 RPMs and leave for some minutes
  • Start the car with the dead battery.
  • Once the dead car engine starts working, remove the black cable connected to a ground location on the dead car, then the black and red cable from the vehicle with the good battery. Finally, remove the red cable from the jumpstarted car.
  • Allow the engine to run for about 30 minutes to charge the battery.

What Will Happen if the Battery’s Positive and Negative side is Interchanged?

Wrong connection of the battery terminals can have a damaging effect on the car and you. Some of the effects of wrongly connecting the battery are:

  • The battery may not hold a charge anymore
  • The battery may explode
  • There is a chance of acid leakage due to overheating the content of the battery.

Furthermore, if the wrong connection is made while jumpstarting the car, the effect will extend to both batteries. The most significant impact is overheating, which can damage the internal and external parts of the cell. It can also lead to blown fuses (circuit protection devices).

jump starting a car

How to maintain the car battery?

Knowing how to connect and jumpstart your car battery without taking care of the battery will reduce the battery’s shelf life. To keep your batteries functional, here are a few tips to take note of: 

  • Switch the battery regularly or disconnect if it will not be used for an extended period.
  • Keep the battery clean of dirt and check the terminals always for corrosion. A brush can do a lot in keeping the battery clean.
  • Give the battery cover as it protects it from external damages.
  • Keep the battery away from excessive heat exposure as heat can reduce the battery’s lifespan.


Knowing the difference between the positive and negative terminals of the battery can go a long way in helping you prolong the life of the battery. The easiest way to differentiate the terminals is to use the + (positive) and – (negative) signs and the color of the wiring. For example, the red wire signifies positive and the black negative. However, if you are still confused about the terminals and how to connect them, consult either a professional or the owner’s manual, as it contains detailed instructions on battery care.

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