Battery Or Alternator: How To Tell Which One It Is

Going somewhere but your car won’t start? There’s probably a problem with your car battery or alternator. There may be possible damage to your car that you don’t know about. It might be your unlucky day if the problem really turned out to be your car battery or alternator since these can be hard to determine from time to time.

Here you will find the signs of a bad car battery or alternator.

Signs It’s A Battery Problem

1.       The car dies immediately

This happens when your battery only has a certain amount of voltage to start the car, but it cannot hold out.

A woman having car trouble while traveling.

2.       Car battery is old

If you know your car is old, your car battery would probably be old too. Car batteries usually last up to 2 to 5 years. Through the years, the metal inside corrodes making the batteries less likely to retain a charge. When it can no longer hold on, it will no longer start no matter how much power the alternator gives.

3.       Corrosion of battery

When checking your battery, you may notice some white powder on the terminals, that may be a result of a chemical reaction. It is important to wear safety glasses and gloves when dealing with hazardous chemicals to avoid infection and contamination from unknown substances.

4.       Check the lights on your dashboard or headlights

If you notice that the lights on your car are quite dim, there may be something wrong with your battery. Even when your car is off, the battery should be giving charge allowing it to turn on the lights, windshield wipers, and windows.

5.       Bloated battery

Upon inspecting, a bloated battery is easy to notice. This happens when the alternator overcharges the battery.

Signs It’s A Faulty Alternator

1.       Dead battery

Since dim lights are also a sign of dead batteries, it’s natural to think that dead batteries are the problem, however, dead batteries do not always point out the battery being the problem. A faulty alternator may be causing this problem since it is responsible for helping power the battery.

2.       The smell of something burning

When you think you smell something funny, like something is burning, you should probably check out the alternator since it may have induced hot wires.

3.       Growling noise

If you hear funny noises that shouldn’t be heard like something growling or squealing, it could mean that your alternator has a problem.

4.       Electrical issues

If your car accessories or car radio are acting up, or there’s an electrical problem in your car, your alternator may have failed since it may obstruct the electrical system with erratic alternator output.

A woman testing the car audio system.

5.       Test your car and battery

Try running your car then unplug the positive battery, if it stops then the alternator is most probably the problem.

6.       Jump-starting won’t work

If you tried jump-starting your car but it still doesn’t work, then the root of the problem is most likely the alternator.

A Simple Solution To Alternator Or Battery Issues

  • Check your car batteries or alternator to see if something is unusual, if you do find something, call for a handyman.
  • If you are knowledgeable about fixing this kind of problem, you must still proceed with caution and remember to wear personal protective equipment.
  • Try jump-starting your car. You may ask for help when you see a car with a functioning battery.

What Should I Do

  • If you are in the middle of the road and your car breaks down, call for help. If possible, before completely shutting down, move your car to the side of the road.
  • Ask a repairman to fix your car, if there is no one available due to circumstances, ask for help from those near you.
  • Do not touch any chemical substances without proper equipment when inspecting.
  • If you smell something burning, the wires possibly may have overheated. Stop driving and turn off everything in your car immediately.
  • You may also take precautions to avoid these problems in the future. Turn off car accessories that consume the car battery without running. When parking, disconnect cables from the car battery when your vehicle is unused to maintain the battery charge.


With all things considered, a car battery and alternator are connected and work together, when the car dies quickly, the lights are turning dim, the smell of something burning, and a funny noise may all be signs of the battery and alternator having something wrong.

Seek help from professionals and always remember to protect yourself when inspecting to avoid complications.

Feel free to comment if there are any more questions and clarifications.

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!

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