What Causes Your Car Battery Light To Stay On?

by Phil Borges // in Car

You are driving in your car, and the battery light comes on. You are not alone if you have noticed that your car's battery light turns on while it is running. It is a scary, frustrating feeling not to know what is wrong with your vehicle.

There may be many reasons why the battery light stays on, and it is important to diagnose the issue before jumping to any conclusions.

We will share with you the possible causes of why your battery light is staying on and how to fix it. By reading this article, you will have an idea of where to start the next time your car's battery light comes on. Let's get started. 

What causes a car battery light to stay on?

The red battery light on your car's dashboard signals a charging problem with the batteries in your vehicle. If this indicator turns and stays lit up, it might be due to damage or a defect of some kind that will need special attention from an experienced mechanic.

If you continue driving with the battery light on, it could lead to a more severe issue that will require your battery to be replaced. If the battery dies, it could cause you to lose power and be unable to operate at normal capacity due to faulty wiring or an alternator that's out of service. The battery powers essential parts in your car, so make sure everything keeps running smoothly.

Common causes of a car battery light to stay on are:

1.Due to a low voltage of a battery

If the voltage of your car battery is below 11V, the battery light will stay on. Check the manual of your car battery to find out how much voltage you need for your particular model of vehicle.

A car battery cannot charge when the voltage is below the required voltage. The vehicle may experience low speed and sluggish acceleration due to less power coming from the engine.

2.Disconnected battery cables

Another reason why the car battery light stays on is due to disconnected battery cables. If the wires are disconnected, the batter will be unable to charge properly.

That is why many people believe that replacing a battery alone might not fix all problems with their car's charging system if there is still an issue with one of these connections.

To fix this issue would be reconnecting or replacing any loose cables so that they are securely attached to both sides of the battery terminals.

3.Failing alternator

The car battery light may also be on because the alternator is failing. The alternator is a charging system component that produces electricity to power your car's electrical system and battery.

To avoid unwanted car troubles, it is crucial to have your alternator checked regularly. It is also best to check out for early signs of a failing alternator, such as:

  • lights dimming
  • car accessories malfunctioning
  • noise in the engine whining
  • there is a smell of a rubber burning
  • and the lights on the dashboard is sending you a warning

To fix this issue, you will need a serpentine belt diagram in order for you to do it yourself correctly. If you are having a hard time in figuring out how to repair your car's alternator, save yourself the trouble by taking it in for professional check and repairs. Those professionals are experts in this field and will give you the assurance that your alternator will receive the repair and proper care it needs.

4.Damaged cells in the battery

Another issue that may cause your car's battery light to stay on is due to damaged cells in the battery. Damaged batteries will need a professional inspection and replacement of individual cells as needed.

This type of repair requires special tools, parts, and skills, so it would be best for you to have your vehicle checked by a mechanic who is experienced in this field.

5.Corroded terminals

When corrosion builds up on the battery terminals, it prevents charge from being transmitted to or received by your battery. If this happens and you notice that your battery light stays on despite starting the car, there is a high chance that the car battery will underperform.

To fix this issue, you will need to clean off all of that corrosion from the terminals with an appropriate cleaning solution such as baking soda paste and water mixture before reattaching securely. Be very careful in scraping off any corrosion that is left to ensure a good connection. Do not forget to wear protective gloves, goggles, and clothing for your own safety.

Frequently Asked Questions

I have a new car battery, and the alternator is working, but the light stays on; what could be the problem?

If you have a new battery installed in your car and the alternator is working correctly, but the car battery light is still on, it could be due to low voltage. You need at least 12 volts for your car's system in order for that charge to flow properly. Another aspect to check is if the battery cables are connected securely. The cables might be damaged or defective and might need a replacement.

Why does my car's battery drain overnight?

Car batteries drain overnight due to parasitic electrical loads. These are battery drains that happen when your car is parked and off or not in use, such as headlights staying on for a long period of time. This issue can be avoided by turning the lights off while parking at night.

Do not leave your headlights on overnight while your car is parked. Don't leave the key in the ignition if you're not using it.

Should I also change the alternator if I changed my battery?

If you have a new battery installed and your alternator is working properly, then you probably do not need to change the alternator. Just make sure to have your alternator checked regularly.

Why is my battery light on and the alternator is working?

If your vehicle's battery light stays on, even when the alternator is charging, it could mean that you might have got a serious issue going on with either your car parts or the wiring of those components. This will lead to improper charging and some costly repairs in order to get back up running again. Ensure to have this checked right away.


To make sure that your car battery light will not stay on, it is best that you have a battery and alternator checked regularly. Keeping your battery and alternator in optimal condition is the best way to avoid any issues. If your battery light stays on, it is best to have the problem checked out and repaired as soon as possible.

This article was written as a helpful guide in determining what is going on with your car battery's light and that it has also helped you understand what causes this problem.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.