What does the battery light mean?
Whenever a warning light comes on on your dashboard, you should always pay attention to what’s going on. If your battery light is on, you may not have much time to fix the problem before your car breaks down. Therefore, you need to diagnose why your battery light is on while you’re driving.
In this guide, we’ll cover the 7 most common reasons why this warning light appears, especially while driving. We’ll also show you what to do if the light comes on. At the end of this article, you’ll find some answers to questions that have been bothering you.
Why does the battery light come on while driving
The battery light can come on if the alternator belt is broken or slipping. It could also be due to a worn alternator, broken pulley, or damaged wiring. It could also be that the battery is faulty, the terminals are corroded, or the engine ground strap is faulty. Watch this video to learn why your battery light is on. We’ll go into this in a bit more detail below.
1. Broken or slipping alternator belt
The V-belt is what keeps your alternator and other accessories working. With proper maintenance, it usually lasts 50,000-100,000 miles. If the belt breaks or starts to slip, you’ll know that your alternator isn’t working properly. This problem also causes a squealing noise, especially when it’s cold outside. If the battery is completely drained, the lights may flicker or go out, and the engine may stall.
2. Generator failure or wear
The generator is responsible for charging the car’s battery while the engine is running. If the generator fails, the battery will not receive the energy it needs. Alternators typically last for 100,000 to 150,000 miles, so it’s not an issue that needs to be repaired often.
There are several signs of a faulty generator, including dim headlights and faulty electrical equipment. If you don’t fix the problem right away, your car’s battery will die.
3. Faulty generator pulley
The V-belt wraps around the alternator pulley as it travels back and forth between the various components. If the pulley is damaged or fails, it can cause a variety of issues with the belt, which can lead to problems with the alternator.
The first sign that something is wrong with the pulley may be a damaged belt. If the belt gets stuck or worn on the pulley, you will notice some damage. During inspection, you may also notice physical damage to the pulley. In addition to a burning smell or unusual sounds, you should also look out for the classic signs that your car battery is dying:
4. Poor Generator Wiring
Your generator powers your car battery, but it can’t do that without the proper wiring and connectors to carry the voltage. If the wiring is damaged or worn out, it will cut off the signal and your battery won’t get the charge it needs to operate.
The result is a dead car battery. This issue will cause your battery light to come on, letting you know your battery isn’t charging.
5. Bad Battery
There’s always the chance that the problem is actually related to your car’s battery. If the battery gets too depleted, the alternator won’t be able to charge it and the light will come on.
The average car battery lasts for 3-5 years. It’s a good idea to check your car battery regularly to make sure it’s in good condition, especially before winter when the cold can have a negative effect on a weakened battery.
6. Corrosion on Battery Terminals
Even if your battery is in good condition, it may not be able to charge. If corrosion occurs on the terminals, the voltage from the generator will not be able to charge the battery. Corrosion occurs when hydrogen gas comes into contact with air.
It can be identified by a white or green substance around the terminals and connections. However, it is highly corrosive, so avoid touching it. We’ll discuss in more detail in a few minutes how to fix this problem.
7. Faulty Engine Ground Strap
The engine ground strap is what connects the negative battery terminal to the body of the vehicle. This is also known as the negative battery cable, and is necessary for your vehicle’s electrical system to function. If the ground strap is not properly secured, it can cause headlights to flicker, warning lights to light up on the dashboard, and problems charging the battery. It can also cause low voltage, problems starting the car, and unusual malfunctions in the electrical system.
How to Fix Battery Light That Lit Up While Driving
When the battery warning light first comes on, it’s best to park your car in a safe place and diagnose the system. Do not continue driving, as the battery or generator could fail at any time. Once you find a place to have your vehicle inspected, follow these helpful tips:
1. Measure the charging voltage while the engine is running
You should use a multimeter to check the battery voltage while the engine is running. With the engine off, the battery voltage should be 12.6 volts. However, when the engine is running, this value will be higher because the alternator has to provide additional voltage.
The actual normal reading will be between 13.5 and 14.5 volts. Anything below or above this indicates a problem with the generator.
2. Check the generator/V-belt
Heat, wear, oil, and the environment can damage the V-belt. Additionally, the pulleys may begin to wear against the belt, leaving visible damage upon closer inspection.
You can also look for signs that the sides of the strap are glassy. If the belt becomes glassy, it can slip, break, or overheat. If you replace the belt yourself, make sure you take note of how to install the new belt. There should be a diagram in your service manual or under the hood.
3. Check the wiring
It’s also important to visually inspect the wiring. You can follow all the wires from the battery to the alternator to check for damage. If you notice any damage to the cables, replace them immediately.
4. Check the Battery
Don’t forget to check your car battery regularly. With a multimeter, you can verify that the battery voltage is 12.6 volts with the engine off.
If you don’t want to check your battery at home, many auto parts stores offer free battery testing. Many of these places will install it for free if you buy a new battery through them.
5. Check the engine ground and battery terminals for corrosion
Test the ground connections, just like we do in our workshop, by following these steps:
Set your voltmeter to ohms to test for resistance.
Check the negative and ground connections. If it measures less than 5 ohms, the ground resistance is good.
To check the voltage, set the voltmeter to DC.
With the accessory powered on, the voltage under load shouldn’t exceed 0.5 volts.
If there’s voltage at any point, you’ll need an additional ground strap or a new ground position.
You may also want to clean any corrosion on the battery to ensure a good connection. Sprinkle baking soda on the corroded area.
Dip an old toothbrush in lemon juice or vinegar and dip it on the baking soda to create a lather.
Leave it on for a few minutes.
Scrub the corroded area.
Rinse with water. To prevent corrosion, you can apply battery terminal grease to the terminals. It is readily available at any auto parts store.
6. Contact a Professional
If any of these steps seem too complicated for your experience, we recommend consulting a professional. We have seen many people causing further damage to their charging system by simply messing with things they should not be touching. You are dealing with voltage, so refrain from working with voltage unless you are ready to take all the necessary safety precautions.
Can I drive my car even if my battery light is on?The vehicle can continue to run normally for a short period of time, so there is nothing to prevent you from driving even if the light is on. However, your car battery can die at any time and cause your car to stop working. For this reason, we recommend stopping immediately and correcting the problem.
Does a battery light coming on mean there’s something wrong with the alternator? This could indicate that there’s something wrong with the alternator and that the battery isn’t charging properly. You should also check the ground connections.
Why is the battery light on but the alternator is fine?The battery light indicates low voltage, which indicates a problem with the charging system. This could mean an issue with the alternator, but it could also be that a problem with the battery, connections, alternator pulley, fan belt, or battery corrosion is causing the charging problem.
How long can I drive with the battery light on?The amount of time it takes for the battery to fully discharge after the light comes on depends on several factors. While the age and condition of your battery are the main concern, the factors that are causing the problem also play a key role. Your car can shut off at any time, although only for 30 to 60 minutes maximum.
How do I know if my alternator is failing?When the alternator no longer provides enough voltage to the battery, your car battery will die. In addition, some of your car’s electronic components may fail or your lights may flicker. If you have a voltmeter on your dashboard, you’ll know that the charge falls into the danger zone.
If the battery light on your dashboard comes on, don’t ignore it. You may want to keep driving, but your car battery can fail at any time and cause your engine to stall. This situation puts you at risk, so you need to act immediately.
If you’re not familiar with working on these parts, we recommend having a professional check your charging system. If you are familiar with the system, it will not be difficult to identify and correct the errors.