[Fix guide] Battery light is ON: What does it mean? What to do now?

Written by

Tim Miller

An automotive mechanic and blogger at obdadvisor.com

Is your battery light on? Read this guide.

Your vehicle sometimes comes with a battery light on the dashboard. This light works as a warning in case the battery has a problem.

The battery is vital for the vehicle’s operation. It runs anything electrical such as the ignition system, the headlights, the radio, and the engine’s control computer, among others. But as vital a battery is, it at times stops working. And there are many reasons for that. It could be a damaged alternator, corroded wires, fuses, or the battery itself. 

In such a case, the battery light will then go on. Unfortunately, not many car owners know what a battery light is for. Also, they don’t know what it means whenever it goes on. And they barely know what action to take in such a scenario.

Here's where you can find out what to do when the battery light comes on
If you want to know what the battery light means, this is the right place

What does the battery light mean?

First, what does that annoying battery light mean when it chooses to illuminate on your dashboard? Contrary to what you might believe, it doesn’t necessarily mean your battery is dead.

A bright battery light means that your car has a problem with its charging system. It could say that your battery is dying, but in most cases, it means that there is a problem within the system. It could be as simple as a loose battery cable that keeps the battery from charging correctly or as complicated as an alternator failure.

Why does my car battery light come ON?

battery light on
The battery light on the dashboard works as a warning in case the battery has a problem.

If your car battery lamp switches on while driving, that indicates that the charging system has stopped working. However, the fault might come from something else besides the battery.

The battery light on can be caused by a rusted or loose battery cable or a wire that connects items in the charging system. 

Alternatively, a problem with a voltage regulator or alternator can make the battery light go on.

The alternator sucks power from a car’s battery. So, if the alternator’s accessory belt is broken or loose, the alternator will not work. 

And all you’ll have is a dead car battery since the faulty alternator will not recharge the battery.

Besides the alternator, the light can come on in case the battery itself has issues. These problems include damaged cells, leaking electrolyte, bad wiring, or rusted cable terminals. 

What to do when the battery light is ON?

Now that you know why your car battery comes on, you should know how to react in such a situation.

These tips will help you to at least get home safely. Hopefully, you always carry your car’s manual – because you’ll need it in this situation.

For one, when the battery light illuminates, do not panic at all. Instead, continue driving as you usually do, which means you should not break any road rules or regulations.

Another thing to do is switch off anything that sucks power from the battery, including the radio, air conditioning, and unnecessary light. If driving at night, just leave the headlights on. 

If driving on the highway, ensure you pull off the road immediately. Drive your car home. If you think you can’t make it home, drive to a secure location. 

Later, you can drive to a local repair garage. The experts here will check your vehicle to see the cause of the problem.

On the same note, ensure you do not switch off the engine. Letting the car stay idle takes less energy than restarting it.

The other thing is to read your car manual. Check the instructions on what to do when the battery light comes on.

Battery light came on while driving and the car died: Why?

If your battery light goes on, you can at least make it to drive to a service facility or at home. As long as there is some juice left in the car battery, your vehicle will continue running. 

However, if your alternator is bad or the charging system is faulty, unfortunately, your car will die because the engine cannot run with a drained battery.

And in case you switch off the car engine, you cannot restart it. This is because the battery barely has enough charge to power the starter motor. 

Find out 8 common reasons why the battery light comes on while driving and the car dies after that: Battery light comes on while driving and the car dies

Is it safe to drive a car with the cattery light on?

Though you can drive with a battery light on, the question here is whether it is indeed safe to do so.

The battery light comes on to indicate a severe issue that needs an urgent diagnosis. Therefore, driving with a battery light on is not a great idea.

The issues making the light come on might make your car lose power. Or worse, the car might not run as it is supposed to.

What does it mean when the battery light comes on and off?

It indicates that the car battery light has taken control over the running of the electronics in your car

When the battery light switches on and off, it means there is a problem with the alternator
Credit: commons.wikimedia.org

There is a circuit that examines the voltage level produced by the alternator. In case the voltage is low, the circuit will switch on the battery light.

On the same note, if the light illuminates and stays like this while driving, a damaged alternator belt is the cause.

When the battery light switches on and off, it means there is a problem with the alternator. It indicates that the car battery has taken control over the running of the electronics in your car.

If the output level – from the car alternator – drops to a really low level, the battery light will flicker. 

Battery light on after replacing battery: Why?

As aforementioned, there are many reasons why the battery light comes on. The battery is one of those reasons. 

So, if the problem is not coming from the battery, the light will still come on even if you replace the battery.

The battery light might illuminate if the alternator belt is loose. If so, have it tightened and see whether the light will disappear. If the problem still exists, let a mechanic test the alternator. 

Alternatively, if there is a damaged wire or poor connection somewhere, then the battery voltage will drop. The best thing is to measure this voltage at the ECU or alternator itself. 

Check whether the battery connectors are in good shape, tight enough, and don’t have frayed wires. Otherwise, you can replace it to check if the results will change. 

How to prevent my battery light from coming on?

What can you do to make sure your battery light doesn’t come on? Here are four tips.

Four tips to prevent your battery light from coming on
Here are something you can do to make sure your battery light doesn’t come on

1. Change your battery before it dies

A standard wet-cell car battery like the one that’s currently under your hood will usually last for five years before it will stop holding a charge. Extreme temperatures — either hot or cold — can affect this longevity. Damage, leaking electrolyte, or corrosion can also cause it to fail prematurely.

Pay attention to how long your battery has been in your car. Most batteries are labeled with the month and year of their manufacture. It will either be on the label between the posts or a small round sticker somewhere on the battery’s surface.

If it’s approaching that five-year mark, change it out for a new one even before it starts to fail. This preventative maintenance can keep you from ever seeing that cursed battery light. This is a job you can easily do at home once you set up your garage with the right equipment to do the job safely.

2. Load test your battery

When the battery is starting your car, it’s under what is called a load — something is drawing voltage from it for a specific task. A healthy, new battery will usually sit at 12.6 volts at rest. When it’s under a load, it shouldn’t drop below 12.2 volts to have enough power to start the engine.

Most parts stores and battery shops will perform a load test for free. If you don’t have one nearby, break out your multimeter, set it to volts, and have someone start the car while you’ve got the leads attached to the battery terminals.

3. Clean your terminals

Loose, broken, or corroded terminals could trigger your battery light. Ensure there is no corrosion on the terminals and that they aren’t broken or bent out of shape.

You can clean corroded terminals with a wire brush or pour a small amount of Coca Cola over them.

4. Test your alternator

A failure in your alternator could also trigger your battery light. If the alternator fails while you’re driving, you could find your car shutting off entirely while you’re trying to drive down the road. Head to your local mechanic or parts store and have them test your charging system — many will do it for free.

A functioning alternator should generate a steady charge between 13.8 and 14.2 volts. This energy is used to power the electronic components of your car while the engine is running. If the alternator fails, your radio, lights, and other electronics will drain the battery until it shuts off completely.

Test your alternator regularly. If it starts putting out less than 13.8 volts, it could be a sign that it’s beginning to fail and will need replacing to prevent your battery light from turning on.

Final thoughts

No one wants to see their battery light — or any of the warning lights on their dash — light up. Some regular testing and maintenance can keep your charging system in good working order and prevent you from ever having to see that hateful light.

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