The role of the alternator is to provide the charge needed in your car to run the electrical system. It does this by turning some of your engine’s power into electricity. But can the alternator drain the battery? Yes and no!
Alternators are one of those robust parts of your vehicle and often will last a long time without needing to be replaced. Often they will last for over 100,000 miles. However what if you notice that your car’s battery is losing charge?
Two situations could be at play here. First off it is possible that your car’s alternator is damaged and cannot, therefore, charge the car battery. Secondly, the alternator itself may be draining your battery of its charge.
At this point, your vehicle will require a diagnosis to find out the real cause of your battery’s lack of charge. You may find that you need to replace your alternator with a new one. You may also find a used and remanufactured alternator helpful and a cheaper alternative.
Let’s take a closer look at the question “can the alternator drain the battery” to help you find out exactly what to do.
- Dead Battery
- Parasitic Draw
- Alternator Or Battery
- Battery Draining Overnight
- Frequently Asked Questions
Dead Battery
There are plenty of factors and causes that could leave your car battery drained. Nothing will put you in a foul mood than waking up in the morning and can’t drive your cool Mustang because it just won’t start.
So the question now becomes what are the various causes that could drain the charge out of your car battery and leave you with a dead battery?
One thing we should point out is that even while a dead car battery is one of the most annoying things, there are steps and measures that you can take to avoid it. For you to prevent a dead car battery, you must find out exactly what could have caused the issue.
Let’s find out.
1. Leaving The Headlights On
If you notice that the car battery is draining quickly and you always wake up to a dead battery, you may want to check if you left the headlights on.
Sure modern cars have a feature that turns off the headlights whenever they are left on for a certain amount of time.
However, many vehicles don’t come with this feature. This would then mean that you need to turn off your car headlights yourself otherwise they remain on and completely drain your car battery of its charger.
2. Loose Battery Terminals
You may find that it is not the battery that is dead but the terminals that are loose or corroded. Such corroded or loose terminals will prevent the battery from transmitting its charge and therefore fails to start your vehicle.
This issue could even cause the car it stalls whenever you are driving or it could end up damaging other electrical components.
You won’t have to worry about this if you drive a Tesla.
To prevent this issue, you can ensure that your terminals are tight and you can clean the vehicle regularly.
3. The Weather Is Extremely Cold Or Hot
The cold winter days or extremely hot summer days could affect your car battery’s ability to hold its charge. A new battery is more able to resist the effects of extreme weather temperatures.
That said, if however, your battery is old, its ability to withstand such cold temperatures or extremely hot days is very limited.
4. No Charging While Driving
To start the vehicle, the battery is required to have a decent amount of charge. However to keep your battery fully charged it must be charging with the help of the alternator whenever you are driving.
But can the alternator drain the battery? If the alternator is damaged it will fail to charge the car battery when driving. You will often find that even after a drive, you are getting a hard start whenever you want to drive again.
Therefore, if you are finding that your vehicle is not starting after driving, there is a good chance that the alternator isn’t working.
5. Frequent Short Drives
Whenever you are cranking your car’s engine, a huge amount of power is needed from the battery. However, the battery is recharged whenever you are driving by the alternator.
That said, if you are taking too frequent drives, you will find that the alternator doesn’t have enough time to recharge your car battery. This is especially the case when your car battery is old.
Therefore taking many short trips will likely drain your car battery and shorten as life.
6. You Have An Old Battery
We have mentioned this several times by now. One thing however that you should keep in mind is that even your car battery is prone to wear and tear and will not last forever.
While your car battery will last upwards of five years this comes down to your location.
If you are taking regular short trips, or you live in areas where there is extreme weather, the car battery may last only two to three years.
If you notice that your car battery is beginning to die quickly this is a good sign that it’s time to replace the car battery with a new battery.
Parasitic Draw
Your car’s electrical components will still get power from the car battery even while it is off. This is why you can listen to the radio even when you haven’t turned on your car.
Such electrical components including the alarm or the radio will not be in a position to drain your car battery. However electrical components such as the interior lights, bad relays, or even door lights on the other hand will significantly drain the battery.
Keep in mind that whenever you are driving your vehicle, the alternator is busy charging the car battery.
This is why it seems that the car battery never runs out of power, provided that is that everything else is working as expected and that the car battery is fully functional. But can the alternator drain the battery? Yes, if it is damaged.
While the engine is not running however the alternator isn’t working and is, therefore, isn’t charging your car battery. This, therefore, means that electrical components and mishaps will be draining the car battery.
It is this battery drain caused by such electrical components and mishaps that are known as a parasitic draw.
To prevent this parasitic draw, ensure that you have turned off all interior lights, and always ensure that you have shut the doors, the drunk as well as the glove box
Alternator Or Battery
The alternator comprises a magnetic motor. When a small charge from the battery is provided, the motor spins, and a sort of electromagnet is created which then results in an electrical charge.
This power will then be sent through fuses and to your vehicle’s electrical system.
Imagine trying to start your car but the car just won’t crank up. It’s one of those annoying experiences. The reason behind your car’s failure to start often comes down to the malfunctioning of both the car battery and the alternator.
The great thing is that figuring out which of the two is the problem isn’t all that hard. This is not an issue you need to worry about with an electric car such as a Rivian or a Tesla.
One thing to keep in mind is that to be able to start and run your car’s engine, 3 main processes are involved.
First off, the car battery will send a decent amount of charge to the car’s starter. This will get the engine to start running. As a result, the alternator will begin to work. Thirdly the alternator which is now running will charge the car battery.
You can find out the cause of why your car battery will not start by bypassing the role of the battery and jump start your car.
But can the alternator drain the battery? If you notice that your engine is starting and then soon dies, then the issue isn’t the car battery. Very likely it is the alternator that is failing to charge the battery.
If on the other hand the engine keeps turning when you turn the ignition key, but the car simply will not start using the battery, then the car battery is likely the one that has the issue.
Signs Of A Bad Battery
Here are some common signs that you have a faulty or damaged battery.
1. Dim Dashboard Lights
You may want to start by having a look at the dashboard battery gauge. Even while the car has been turned off, the battery needs to be charged. If you notice that the dashboard car battery lights are dim, then there is something wrong with your car battery.
Turn on the windshield wipers and see if they are functioning. You could also try turning on the internal lights. You will then need to turn them off if you are to try and start your car again.
2. See If There Is Corrosion On The Battery
Take a look at your car battery and see if you can find any corrosion. Try and wipe this off using a dry towel and then try to jump-start your vehicle. Run the car motor for a while and then turn it off.
If you notice that you are getting a hard time trying to restart the car, then this could show that the alternator is working by keeping the engine running but the battery is failing to hold onto its charger.
Can the alternator drain the battery? Let’s not forget that it can if it is damaged.
3. You Have An Old Battery
Old batteries are less likely to keep the charge since the metals inside the batteries are corroded. You can expect car batteries to last anywhere between 3 years and 5 years.
As the car battery becomes older, it gets to a point where it cannot hold even the slightest amount of charge as the metals inside the battery are so corroded. At this point, it would be hard to start the car battery.
4. Your Car Radio Will Not Turn On
Whenever you turn on your ignition, you should also be able to turn on the car radio, the wipers as well as the different other electrical components in the car.
If you notice that your car stereo isn’t working or if the interior lights or the headlights are dimming, then this is a sure sign that the car battery doesn’t have enough charge.
5. The Car Starts And Then Immediately Dies
Several reasons could cause your car to start and then immediately die. One of the reasons included issues with the car battery.
This is one of those less common problems and is usually caused when the car battery simply lacks enough charge and only has a charge to start the vehicle.
6. A Swollen Battery
It is hard to find out of you have a swollen battery. That manufacturer’s design simply allows you to tell if the battery is bulging.
If there is a faulty voltage regulator, the alternator will overcharge the battery which will then cause it to bulge.
Signs Of A Bad Alternator
If using the above steps you notice that there is nothing wrong with the car battery and that it is working perfectly, then the next place that you should check is the car alternator.
Can the alternator drain the battery? Yes if it is damaged.
There are several symptoms of a bad alternator that will inform you if you need to replace your car’s alternator.
Can The Alternator Drain The Battery, Symptoms #1: Dimming Of Interior Lights
Let’s say you were driving your car and you had turned on the interior lights. If you notice that the interior lights are gradually dimming, then this could show that the alternator is failing to charge the car battery and that the charge in the battery is always diminishing.
Can The Alternator Drain The Battery, Symptoms #2: Overly Bright Or Dim Headlights
Another way that you can tell if the alternator is working as it should is if you find that the headlights are becoming overly bright whenever you step on the gas pedal and accelerate or they are becoming overly dim when slowing down.
This is a sign that the alternator is not working as it should and isn’t properly charging the car battery.
Can The Alternator Drain The Battery, Symptoms #3: Growling Noises
The alternator will sometimes produce a growling noise whenever you are trying to start your vehicle. This is usually a sign that precedes total damage to the car’s alternator is a sign that you should get a replacement.
Can The Alternator Drain The Battery, Symptoms #4: Burning Smell
If you start to notice a burning smell like rubber or wires burning then this is usually a sign that the alternator is overheating. The burning rubber smell comes from the wire coatings.
This is also a sign that the wires are burning and that you need to replace the alternator. Can the alternator drain the battery? Yes, if it is faulty.
Can The Alternator Drain The Battery, Symptoms #5: Test The Alternator
You can also test the alternator itself to find out how well it is working. Some people would suggest allowing the engine to run while not connecting the negative terminal to the car battery.
However, there are much better ways to test the alternators this method would likely cause damage to the car’s electrical system and components.
Car Battery Draining Overnight
It can be both frustrating and annoying trying to start your car and get on with your day only for it to fail.
There are plenty of factors that could cause your car to fail to start whenever you turn on the ignition key.
One of the more common problems begins when your car will not start in the morning because of the car battery draining overnight.
The car battery sends power to the starter which then causes it to crank the engine and starter engine. This, therefore, means that if the car’s battery doesn’t have enough charge, then it will not cause the engine to start.
One thing to keep in mind is that just because the car battery lacks charge doesn’t mean that you should replace it. There are several causes of car battery draining overnight which are not hard to fix.
Reasons that could cause a car battery to drain overnight include:
Can The Alternator Drain The Battery, Causes #1: Leaving Accessories Turned On
The number one cause of the car battery draining overnight is human error which results in leaving the components open.
Coming home while being tired from work could cause us to leave components running. Sometimes we won’t even remember to turn off the car’s electrical system and interior lights.
For instance, it would even be hard to notice that the interior lights are on during the daytime.
Whichever the case, leaving the electrical components turned on will drain the charge out of the battery.
That said, modern cars will come with an alert system that will inform you that you’ve left electrical components turned on when trying to leave the car.
Can The Alternator Drain The Battery, Causes #2: Parasitic Drain
Another major factor that could cause the car battery to drain overnight is a parasitic drain. This results in the car battery losing charge. This causes the car battery to lose charge overnight when while having turned off the ignition.
Keep in mind that just because you have turned off the ignition doesn’t mean that the car battery isn’t left powering other features such as the anti-theft features and the clock.
When there is a parasitic drain, the charge goes to other components that shouldn’t be working whenever the car is off.
Several factors could be behind the parasitic drain such as turning on of the glovebox lights, turning on the headlights, and leaving the cabin lights on.
If there are defective fuses, poor wiring, and bad car battery installation then this could also cause a parasitic drain.
Can The Alternator Drain The Battery, Causes #3: Extreme Temperatures
If the weather is extremely cold, then just leaving your car battery overnight is enough to drain the charge.
This is because cold temperatures affect the chemical reactions that are inside the car battery. Leaving the car battery for even longer will being the chemical reactions to completely stop.
On the other extreme hot weather can cause your car battery to drain overnight. This is because it will evaporate the chemical inside the batteries during the day and cause the change to drain out during the night when the battery s left ideal.
If you live in an environment that’s extremely cold or hot, it is a good idea to keep the car in a room that has good air conditioning.
Can The Alternator Drain The Battery, Causes #4: Having An Old Car Battery
Old age is one of these factors that could cause the car battery to lose charge overnight. Think of your mobile phone and how over time the battery doesn’t last as long as it used to when it was new. The same is true with the car battery.
When your car’s battery becomes too old, for instance, you will need to make a replacement. It’s advisable to replace the car battery after 3 or 4 years. Not replacing your car battery after the recommended time will increase the chances of the battery dying overnight.
Can The Alternator Drain The Battery, Causes #5: Damaged Alternator
The alternator helps to charge the battery and the electrical system after the car has been turned on. The alternator will be connected to the crankshaft using the serpentine belt. Can the alternator drain the battery? A faulty alternator could end up draining the car battery instead of charging the car battery.
If you drive short distances on a regular, you could also drain your car battery. This is because the alternator doesn’t have enough time to charge the battery.
To help keep your car battery from draining overnight you must leave the car engine running for at least 10 minutes. This will ensure that the battery gets enough charge.
FAQs On Can The Alternator Drain The Battery
Why Does My Car Battery Keep Dying
Among the more common causes of the car battery dying include corroded terminals, issues with charging, faulty alternator, frequent electrical drain as well as extreme weather conditions.
How To Tell If Alternator Is Draining Battery
You can tell if the alternator is working properly by doing a battery test. This is simple to do and requires you to start by opening up the hood of the car. While the car’s engine is still running, take out the negative terminal. If you notice that the engine dies or is stalling then there is a chance that the alternator is faulty.
Can A Car Battery Die While Driving
Yes, the car battery can die while you are driving. This however isn’t to say that the engine will stop running. The problem is that you will not start again after turning it off. It is the alternator that will be providing the engine with power whenever you are driving.
