We’ve all been through this scenario. You’re driving along when suddenly the battery light come on and you don’t know what to do. You are probably are getting worried about a serious malfunction with your electrical system. But what does it mean when your battery light comes on while you are driving?
The car’s electrical system works with a battery to supply voltage and an alternator to recharge the battery. As you turn on the ignition switch, the battery powers the starter motor and turns the engine over. The alternator starts spinning under power from the crankshaft and replenishes the battery charge as you drive. On engine start up, the battery light will flash for a second and disappear. But if the battery light stays on while you drive, there could be a problem with the charging system. You should be aware of potential problems when the battery light comes on while driving.
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Why Does the Battery Light Come on?
The simple answer is that the battery is not being charged by the alternator when the battery warning light flashes on instrument cluster. The cars ignition systems and electrical accessories are now being running on battery power alone, which will run out in about 30 minutes of driving. Your engine will shut down after this time and you will not be able to restart the car.
The first thing to do when you notice the battery light on in car is to switch off all electrical accessories. This includes the air conditioning system, stereo and subwoofer, infotainment system, external LED light bars and any device charging through the power outlets (smartphone and USB chargers).
If possible, try to drive to the nearest service station to rectify the electrical issue. Otherwise, stop the car at a safe place and call for vehicle recovery. The power steering and electronic stability programs could malfunction, leading to an accident. Remember if you happen to turn off the car, it may not restart due to the battery being drained of charge. You could drive home if it is a short distance, but it is better to avoid a risk.
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Reasons Why You Have a Red Battery Light on Dashboard
Dashboard warning lights are usually straight forward and the red battery light on dashboard is no different. However, there could be some underlying issues that you may have to address before you can start driving normally again.
So, what does the battery light mean? The following are a list of potential problem areas to look into when you see the battery light on while driving.
The alternator is an electrical generator that spins under the power of the engine’s crankshaft. It provides voltage to charge the battery as well to power electrical accessories like headlights, stereo, Ac, etc.
If there is a problem with the alternator, or the voltage regulators (rectifier unit, etc.), it will not charge the battery effectively. The car’s electrical system will start draining power directly from the battery which will last only for 30-45 minutes. Once the battery is drained of power, the car engine will shut down and it won’t restart. There is not enough voltage in the battery to power the ignition system and electrical accessories for long.
A bad battery will trigger the battery light on in car while driving. The battery light comes on and off as the voltage varies and may confuse some drivers thinking that the problem is going away. Batteries usually have a life of 3-5 years depending on proper usage and can get damaged over time. One of the common problems is battery electrolyte acid leaking from the reservoir and corroding the battery terminals. Sometimes the battery cables get loose or damaged and will not conduct sufficient current.
The battery will discharge quickly and the alternator will not be able to recharge it. Check the battery for signs of corrosion and ensure that the battery cables are in good working order.
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These belts transfer power from the engine crankshaft to the alternator as well the water pump, air compressor and power steering unit. Worn out V belts or serpentine belts will not spin the alternator to the right rpm, and voltage produced will be lower than required. You might see the battery light on while driving which indicates low voltage and insufficient charging of the battery.
You may also notice engine temperature rising and difficulty in steering because the coolant pump and power steering unit are not being powered properly. It is not safe to drive with battery light on in this situation.
As discussed, the battery light on while driving could be a sign of a minor problem like replacing the battery or reconnecting the cables, or a much more serious problem that requires looking into the alternator and electrical components that are used to recharge the battery.
Addressing the problem as soon as you identify the battery light on the dashboard could save you a lot of time and money at the mechanic shop.
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Frequently Asked Questions
Q1. What Does It Mean When the Battery Light Comes on?
Ans. The battery light is a dashboard indicator that lets you know there is something wrong with the electrical charging system in your car. The alternator is used to charge the battery while driving, so problems with the charging system can trigger the battery light. A damaged battery or corroded electrical wires and connections may also cause the battery light to illuminate, indicating that it should be fixed. If the battery light came on while driving, turn off unnecessary components that draw power such as the air conditioning system, stereo, interior lights or any USB devices that are charging through the power outlet.
Q2. Why is My Battery Light on?
Ans. The dashboard battery light may come on when there is a loose battery cable or when battery terminals are corroded, preventing sufficient voltage from reaching the electrical system. A faulty alternator will not be able to recharge the battery causing it to lose charge while driving and eventually fail. Sometimes the battery cells or plates may be damaged causing low voltage through the system. For all these cases, you might see the battery light flashing on your dashboard. Drive to the nearest mechanic and check the electrical system as soon as possible.
Q3. What Would Cause a Battery Light to Come on?
Ans. There are several reasons why a battery light may start flashing on your instrument cluster. Some potential problems are a dead battery (batteries usually last for 3-5 years) which needs to be replaced. A damaged alternator which is not producing the correct voltage to recharge the battery. Worn out alternator belts cannot spin the alternator fast enough which may cause a drop in voltage. Often battery terminals get corroded due to battery acid leaking or engine heat. The battery light could illuminate when too many accessories are being used (stereo, air conditioning, device chargers).
Q4. What Does It Mean if Battery Light Came on and Car Stopped?
Ans. If the battery light comes on while driving, it is a sure sign that the battery is not receiving enough voltage from the alternator. The battery will slowly get discharged up to the point when there will not be enough voltage for ignition. The car engine will then turn off and it would be impossible to start the car because the battery will be completely drained. When you see the battery light in the instrument cluster, turn off all electrical accessories such as stereo and air conditioning and drive to the nearest service centre to get the electrical system checked out.
Q5. What Does the Battery Light Mean in a Car?
Ans. All internal combustion cars have a 12 -volt battery which is used to start the engine and provide electrical supply for the ignition system, spark plugs are interior accessories. The alternator is driven by the engine’s crankshaft and recharges the battery while driving. If either the alternator is not providing sufficient voltage, or the battery is faulty, you should see the battery light coming on the dashboard while driving. It is normal for the battery light to flash when starting the car, but it should disappear once the engine is running.
Q6. How Long Can You Drive With Battery Light on?
Ans. The battery light indicates that the battery is not being recharged. You will have approximately 30 minutes to 1 hour before the battery completely discharges and the car engine stops. Running electrical accessories such as LED light bars, music system, air-conditioning, devices charging from the power outlet will drain the battery faster, meaning you may have less than 30 minutes of battery charge left.
Q7. What Can Cause the Battery Light to Come on?
Ans. The battery light could come on due to a faulty electrical system. Check the alternator for proper voltage generation to ensure that the battery is being charged while the engine is running. If the battery is more than 3 years old, check the electrolyte levels and cells for signs of damage. A bad battery should be replaced as soon as possible. Other reasons for the battery light illuminating could be corroded battery cables or faulty terminals.
Q8. Is It Safe to Drive a Car With the Battery Light on?
Ans. It is advised to seek help from a mechanic if you see the battery light on. Certain accessories on the car such as the power steering, brakes and traction control rely on a constant voltage to work properly. A flashing battery light could cause these components to malfunction which could be a safety issue. Other electrical components like the ECU could get damaged as well. There is a possibility of the car engine shutting down without warning.
Q9. What Does It Mean When a Red Battery Light Comes on?
Ans. The red battery light could indicate a problem with the alternator, battery or other parts of the electrical and charging system in the car. It could be a minor problem such as a malfunction rectifier unit, blown fuse or cabling short circuit. But don’t rule out major problems such as a faulty ECU or bad battery which will need replacing.
Q10. What to Do if Battery Light Comes on While Driving?
Ans. If the battery light comes on while driving, follow these steps:
- Check the battery for proper voltage with a multimeter. Inspect the terminals for signs of corrosion or leaking battery acid.
- Test the alternator. It should produce sufficient voltage to charge the battery.
- Look at the alternator belt for signs of cracking, wear and tear.
- Test the fuses and replace any blown ones.
- Turn off all electrical accessories that may drain the battery.
Q11. Why is My Battery Light on but Alternator is Charging?
Ans. If the alternator is charging properly and you find that the battery light is on, there could be a problem elsewhere. Check the wiring connections, battery terminals and fuses. The alternator has a rectifier unit to convert AC to DC so that it can recharge the battery. Sometimes the RR unit malfunctions which may cause the battery light to come on while driving.
Q12. Can a Fuse Cause Battery Light to Come on?
Ans. A blown fuse could be a cause of the battery light to come on. Excessive voltage in the electrical system can blow the fuse and prevent charging of the battery. A electrical technician can replace the fuse quickly and it an inexpensive fix. Running the car engine with a blown fuse may cause the battery to drain completely and fail to power the ignition system or starter motor when you need to start the car.