As a car owner, you need to acquaint yourself with the various lights on your car’s dashboard and their different messages. Some lights car turn on and stay for days, sometimes for weeks before the actual fault the light was projecting begins to manifest.
One of the experiences you shouldn’t take lightly is when you find your car battery light on. Unlike some other light signals whose faults may take a while before their impacts are felt.
Once your car’s battery light on dash is on, within a few minutes, the real problem will unfold by stalling your car’s engine or battery not charging. Sometimes, this situation could leave you stranding until you get help.
It is essential to understand your car’s battery light’s message and how to fix the issue. The following sections will unveil what it means for your car’s battery light to be on and how to resolve the problem when you experience it.
What does the battery light mean?
The main purpose of your vehicle’s battery light is to warn you if the recharging system has failed in some way, meaning that your battery is no longer charging and is simply running on whatever charge it has left.
The light works on a circuit that measures the voltage produced by the alternator – the light turns on if the amount of voltage produced is low.
Basically, the light indicates a battery charging problem. If the light comes on and stays on while driving, this means that your alternator is running solely on energy stored in the battery.
If you continue driving, your battery will eventually drain and your vehicle will stop working.
Why Your Battery Light Turns On?
To find out what’s causing the red battery light to stay on, you first must know what to look for. And to help you with this, I’ve compiled a list of probable causes, with a short explanation for each.
#1. Faulty alternator.
The infamous red battery light flashing on your dashboard primarily indicates potential issues with your vehicle’s alternator.
The alternator could fail due to various reasons, including mechanical wear or damage to its essential moving components such as the rotor, slip ring, and brushes.
Additionally, electrical issues caused by a faulty rectifier or voltage regulator could also be the culprit. As a result, the alternator may not be able to generate sufficient charge, or in some cases, any charge at all.
#2. Slipping The alternator pulley.
The alternators in most modern cars have a pulley with an integrated clutch mechanism inside it. It effectively disconnects the alternator from the aux belt when no charging is needed and slightly improves fuel economy.
But such a pulley may get stuck in a disconnected position, and the alternator will lose its drive. This disruption leads to a decline in battery charge, which in turn triggers the activation of the red battery light on your dashboard.
#3. Damaged battery.
The battery, even if worn or flat, will rarely cause this warning light to come on, despite the symbol suggesting so. But if it’s been fully discharged in the past, one or more cells inside it might’ve warped, which creates an internal electrical short.
And if that has happened, the battery will not be able to take sufficient charge and will have to be replaced. In addition, if you have a traditional, wet-cell battery, it might be low on acid, and topping it up with distilled water might solve the problem.
#4. Corrosion on battery terminals.
Another potential battery-related problem that could prompt the battery light to illuminate is corrosion on its terminal, which usually appears because of overcharging or acid leaks.
If substantial enough, these whitish, powder-like buildups will increase the resistance between the battery terminals and lead clamps, consequently obstructing electric flow.
Luckily, corrosion can be easily cleaned off with warm water and baking soda. Loose cable clamps will have a similar effect, which predictably will be solved by tightening them up.
#5. Wiring issues.
Any damage to the wires that connect the alternator and battery to the rest of your car’s electrical system can disrupt the charging system and prompt the battery light to activate.
Similarly, if wire connectors become loose, akin to the lead clamps, you might experience the same issue.
To address this, an immediate inspection of the two main grounding strips is recommended.
One of these strips links the engine to the chassis while the other is connected to the battery. Another typical point of failure that demands attention is the thick red wire that runs from the alternator to the battery.
#6. Broken dashboard wire.
Most cars have a wire running from the alternator to the ECM or the dashboard, through which the signal about the charge level goes.
Because it’s usually made from thin cable, this wire might get physically damaged or corroded. This causes false readings, which trick the EMC into thinking there’s something wrong with the charging system and triggering the light.
#7. Broken or loose aux belt.
Lastly, we have the auxiliary or serpentine belt, which drives the alternator and several other components. Depending on the model, this can include the coolant pump, AC compressor, and power steering pump.
And if the belt is loose or snaps, all of these will be out of action, will cease to function, often leading to the battery light illuminating. You may also notice that the steering becomes stiff, or the air conditioning ceases to work.
However, keep in mind that some cars have electric power steering, which will continue to operate in this situation. Furthermore, if it’s chilly outside, your air conditioning would naturally be turned off, making it less noticeable.
How to Diagnose an Illuminated Battery Light?
If you aren’t familiar with your vehicle’s electrical components or lack technical expertise, it’s best to leave the diagnosis to a seasoned professional.
Here’s how a mechanic will diagnose your battery light:
#1. Inspect the Battery.
In some vehicles, hydrogen gas from the battery acid can cause corrosion on the terminals, especially in warm climates. This buildup can weaken battery connections and interfere with the flow of electricity.
Your mechanic will remove the battery terminal covers and look for white or greenish residue to check for a corroded battery cable. They may use a baking soda mixture or a battery cleaner, along with a bit of elbow grease, to clean grime and battery corrosion.
#2. Tighten the Cable Clamps.
Your mechanic will check the clamps on the battery terminal to ensure they’re securely fastened and that the battery connections are stable.
If the clamps are loose, they’ll use a small wrench or pliers to tighten them snugly around the terminals, helping restore proper electrical flow.
#3. Check the Alternator Output.
The mechanic will check your alternator for loose connections or damage. Then, they’ll use a voltmeter to check if the battery terminals have normal voltage output between 13.8 and 14.5 Volts when the engine is running.
They’ll also listen for unusual noises, such as grinding or whining, that can indicate an alternator issue.
#4. Examine the Serpentine Belt.
If you notice overheating and loss of power steering along with a lit battery indicator, you might have a bad serpentine belt.
The mechanic will look for major cracks or breakages in the belt and ensure it has proper tension. A loose belt can cause squealing noises and fail to drive critical components like the alternator.
#5. Check the Fuses.
While fuses don’t directly control battery charge, your mechanic might still check for blown fuses and replace them if necessary.
A blown fuse can disrupt vital systems like the alternator or charging circuit, which are essential for keeping your battery healthy and properly charged. It can trigger the battery light by cutting off electrical power to the alternator or charging system.
The good news is that many battery light issues are preventable with a little routine care.
How to Fix Car Battery Light On?
At the first sign of the battery warning light, it’s best to pull the car off in a safe location to diagnose the system.
You don’t want to keep driving because the battery and/or alternator could fail at any time. Once you have a place to look at the vehicle, follow these helpful tips.
#1. Measure Charging Voltage While Engine Running.
With your multimeter, you want to check the voltage of the battery while you keep the engine running.
With the engine off, the battery should measure 12.6 volts. However, when the engine is running, the alternator should provide extra voltage, so that number should be higher.
In fact, a normal reading would be 13.5 to 14.5 volts. Anything lower or higher than this indicates a problem with the alternator.
#2. Inspect The Alternator/Serpentine Belt.
Heat, abrasion, oil and the environment can all take a toll on the serpentine belt. Plus, the pulley can start to wear against the belt, leaving behind visible damage if you look for it.
Once the belt gets 50,000 miles on it, you should check it regularly. If there’s any sign of wear or damage to the belt, you want to replace it. It’s especially important to replace any belt with cracks, splits or fraying before it fails.
You can also look for signs that the belt is glazed on the sides. If the belt becomes glazed, it can slip, crack or overheat.
If you plan to replace the belt on your own, make a note of how the new one goes back on. There should be a diagram in the service manual or underneath the car hood.
#3. Check The Wiring.
It’s also important to perform a visual inspection of the wiring. You can trace all of the wiring from the battery to the alternator to see if there’s damage.
If you notice any damaged wires, it’s important to replace them right away. Make sure you also inspect the connectors where the wiring is attached.
#4. Check the Battery.
Don’t overlook the importance of checking the car battery regularly. You can use a multimeter to ensure the battery voltage measures 12.6 volts with the engine off.
If you don’t want to check the battery at home, you can get free battery testing at many auto parts stores. Many of these locations will also install the new battery for free when you purchase it through them.
#5. Inspect Engine Ground And Battery Terminal Corrosion.
Test the ground connection with these steps, just as we would in our very own shops.
- Set the voltmeter to read ohms to test resistance.
- Probe the negative terminal and ground connection.
- If the reading is less than five ohms, the ground connection resistance is good.
- Set the voltmeter to DC current to check voltage.
- With the accessories on, the voltage should not go higher than 0.5 volts under load.
- If there’s a place where voltage is present, a bonding strap needs to be added or you need a new grounding location.
Additionally, you can clean battery corrosion to ensure a proper connection.
- Sprinkle baking soda on the corrosion.
- With an old toothbrush dipped in lemon juice or vinegar, dab it over the baking soda to make it fizz.
- Leave it to sit for a few minutes.
- Scrub away the corrosion.
- Rinse it with some water.
To prevent corrosion, you can apply some battery-terminal grease on the posts. It’s simple to find at auto parts stores.
#6. Contact A Professional.
If any of these steps seem to be too complicated for your experience level, it’s best to reach out to a professional. We’ve seen many people do further damage to the charging system simply because they messed with things that shouldn’t be touched.
Additionally, there are some minor dangers associated with the working on the car battery and alternator. Because you are working with voltage, it’s best to refrain unless you are prepared to take all safety precautions necessary.
Can You Drive Your Car With The Battery Light On?
While an illuminated battery light may not initially prevent your vehicle from driving, commuting with the battery light on is not advisable. Here’s why:
- Loss of power: The battery light indicates a problem with the battery or charging system. If the alternator is not charging the battery, the car will eventually run out of electrical power. This can lead to the vehicle stalling and can cause a breakdown.
- Damage to other components: Ignoring the battery light can result in more severe damage. A failing alternator, for instance, can cause other electrical components to malfunction, leading to costly repairs.
- Safety concerns: Safety is a crucial factor. A car that stalls unexpectedly can be dangerous, especially at high speeds or in heavy traffic. Addressing the battery light promptly ensures your vehicle remains reliable and safe to drive.
Preventing Car Battery Light Issues
While it’s impossible to completely eliminate the risk of car battery light issues, there are several steps you can take to reduce the risk:
Regular Maintenance
Regular maintenance is essential to prevent car battery light issues. Here are some things you can do:
- Check the battery voltage regularly
- Check the battery terminals for corrosion or loose connections
- Check the alternator belt for signs of wear or damage
- Check the fuses to see if any have blown
Avoiding Deep Discharging
Deep discharging, or allowing the battery to drain completely, can cause permanent damage to the battery. Here are some tips to avoid deep discharging:
- Turn off unnecessary accessories when the engine is off
- Use a timer or alarm clock to remind you to turn off the engine
- Avoid leaving the headlights or other accessories on for extended periods
FAQs.
Q: How long can you drive with the battery light on?
If you are asking how long can you drive with the battery light on, here’s a suitable response for you.
You could manage to drive your car with the battery light on for an average of 15 minutes or thereabout. The battery light is a sign that either the battery or any of the components that link up with it is faulty. Hence, the car is likely to stall after driving for a while.
It is better to park your car and check to find out what could be wrong or take the vehicle to a professional auto mechanic to check out the problem and fix any fault discovered as being responsible for the battery light turning on.
Q: What do you do when the battery light comes on?
When you find your car’s battery light on while driving, turn off every electrical component of your vehicle immediately, except the headlights. It enables you to conserve the level of charge that is left in the battery.
After that, proceed to inspect the car’s battery to see whether there are any loose connections or any corroded part of the battery that may be responsible.
If any, clean the corrosion and tighten the connections. Then, check the alternator to see whether there are any defects on the connections to fix them.
You can also check whether there is a faulty or blown fuse that may be the reason for a termination in the flow of electricity between the battery and the alternator.
If this is the problem, you should change the blown fuse. After that, run a quick test on the battery by starting your car.
If it starts, congratulations, you’ve fixed the issue. But, if it doesn’t, you may have a bad battery. You have to consult an auto mechanic to do a proper check.
Q: How can you tell if it’s the battery or the alternator?
It is simple to differentiate the faults linked with a car’s battery and those connected with the alternator. If your car’s engine starts and dies down immediately, the issue is with the alternator, probably because of its inability to keep the battery charged.
In contrast, if your car always requires a jump start to turn the engine on and it usually won’t start on its own without a jump-start, you likely have a dead battery that needs to be replaced.
Therefore, you could find your car’s battery light on but the alternator is charging probably because your car’s battery won’t hold a charge.
Q: Can a bad fuse cause the battery light to come on?
Yes, it can. If the safety fuse breaks, the electricity supply from the alternator to the battery and vice versa will be altered.
The termination of the power supply between these two components will automatically send a signal that causes the battery light to turn on immediately.
It would be best to check to see if there is a blown fuse in the process of ascertaining the reason why your car’s battery light is on. If this is the case, kindly replace the blown fuse immediately.
Final Words
When you see your car battery light on, as part of your safety measures, you need to take action immediately to find out the cause of the problem.
Once the problem is discovered, ensure to fix it immediately without wasting time. It is easier and cheaper to solve a problem at the initial stage.
If you find it difficult to ascertain the fault that could be responsible for the reason why you find your car battery indicator red, contact an expert mechanic to do a proper check and unravel what could be wrong with your car’s battery or any of the related components.