Can A Dead Battery Damage The Car Alternator
It is a common occurrence to find the car battery completely drained out after overnight parking or after leaving the car parked for several days.
This is commonly due to mistakenly forgetting to put off the indoor lights or other power consumers during this period or as a result of another parasitic battery drain.
A car battery is only required to get the car started the alternator takes over immediately after. So, if one can get the car started, can the alternator work to get the dead battery recharged without sustaining any form of damage?
There are reports from those who have attempted to pull this stunt and discovered the battery did not get charged with the drive.
Their car mechanics are undecided regarding the cause for a damaged alternator. How true is the claim that an alternator can get damaged this way?
A good number of car owners claim to have used the cars alternator to recharge a dead car battery back to life without causing any form of damage to their alternator.
A weak battery should however go through deep charging before getting connected to the alternator.
If the alternator fails to charge the dead battery back to life, does this automatically mean the alternator has become damaged? This may not be the case.
There are other reasons or explanations for an alternator failing to charge the car battery, this could be as a result of the battery being dry or damaged.
Engine Stalling Or Slow Cranking
Another sign of a failing alternator is if your car starts stalling. This typically happens because your cars power is fluctuating.
As a result, when your power is too low then your car will begin to stall.
Another sign is if your car is cranking very slow.
This will happen becuase your alternator is not working properly. Your alterntor will crank very slow or not crank fully. As a result, your car wont run and also your car wont be able to generate enough power.
A Problem In The Alternator Voltage Regulator
The voltage regulator of the alternator is what controls the electricity in your car. If it is not working properly, then it can cause the battery to not charge. This will cause your car to die.
There are a few things that you can do to troubleshoot this problem on your own:
First, check the connection between the battery and the voltage regulator. If it is loose, then this can cause the voltage regulator to not work properly.
Second, check the fuses that are associated with the alternator and the battery. If any of them are blown, then you will need to replace them.
Third, test the resistance of the voltage regulator. This can be done with a multimeter. If the resistance is not within the correct range, then you will need to replace the voltage regulator.
If you are still having problems after doing all of these things, then you may need to take your car to a mechanic and have them look at it.
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Signs Of A Bad Car Battery
Here are some common signs which can tell you that the problem is not with the alternator:
The Engine Starts Slowly or Wont Start
Your car starts and dies immediately for several reasons, however, checking the battery in the first place is essential. You can also use jumper cables and try to start it. Here is how you can deal with a dead car battery.
Battery with Corrosion
As long as the battery terminals are corroded, they disable electrical power so the car battery cannot receive the proper charge. Excessive corrosion on a battery may need a prompt replacement or the removal of the battery corrosion.
Expired Battery
In general, the useful life of a car battery is between 2 to 3 years. Old car batteries easily accumulate corrosion due to leaks and deterioration from continuous use. The old car batteries also cant hold enough power to start the car. It is best to replace the car battery for a smooth ride.
Strange Smell
A lead acid battery releases sulfuric gas, giving off the strange and unpleasant smell of rotten eggs. If you detect battery leakage, it is best to replace it immediately.
You can also test the cars battery performance, in case you are dealing with these symptoms. Testing a battery can be done with a voltmeter or taken to specialist stores where it can be checked.
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Can A Completely Dead Battery Be Recharged

While your vehicle’s alternator can keep a healthy battery charged, it was never designed to completely recharge a dead car battery. … With a seriously depleted battery, your best option is to connect it to a jump starter or a dedicated battery charger either before or immediately after a jump-start.
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Why Does The Starter Motor Grind Or Click
Ignition combined with a no-start can indicate a bad starter motor or a problem with the starter solenoid. If there are grinding sounds with a no-start, it could be the sound of the starter motor teeth misaligning with the flywheel teeth.
Continuous cranking in this condition can result in more serious, costly damage.
Growling Or Squealing Noises
Growling or squealing from your vehicle is never a good sign.
If the squealing gets louder when the heater or sound system is on, you could very well have an ailing alternator. These sounds could also be from a misaligned alternator belt rubbing against the alternator pulley.
Another way to pinpoint a failing alternator is to turn on the AM radio to a low dial without music and rev the engine. A resulting whining or fuzzy sound could point to an alternator problem.
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How Can I Test My Car Battery At Home
Connect the positive and negative battery connections to the multimeter. You may have a faulty battery if the voltage isnt around 12.6 volts. Now start the vehicle and check for a voltage reading of more above 10. When the voltage dips below 5 while the automobile is operating, it is defective and should be replaced immediately.
Can A Blown Fuse Drain A Car Battery
Sometimes. A blown fuse can cause other components of your electrical system to malfunction so eventually the car battery could become drained, but a blown fuse definitely does not immediately drain a car battery.If the alternator goes out, that will indeed drain your battery, and the light on your dashboard will go from green to red letting you know its time for charging.
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How To Test Your Battery
There are effective and inexpensive battery testers that you can purchase online. You can also use a simple multimeter or voltmeter.
To test you would adjust your multimeter to 20DC. Then place your red probe on the postive battery terminal and the black probe on the negative battery terminal. Once both probes are both on the terminals you will get your reading.
If your battery is not giving you a proper reading after both situations, this is a sign that your battery is dying, and you should test further.
A good battery should read between 12.2 and 13 volts when the car is off.
If the car is running, your battery should read between 13 volts and 14.8 volts.
If you experience anything outside of these ranges, this is a sign your car battery is draining and not being replenished.
Its important to note that if your engine is reading higher than the range for a good battery, this is a sign of a faulty battery or issues with the alternator.
Signs Your Alternator Is Failing
One of the easiest ways to discover if your alternator is failing is by looking at your dashboard. If you see a warning indicator lightwhich may read ALT or GEN depending on your vehicle make and modelyou know that your alternator is having some issues. Another sign is if your headlights are dimmer than normal or are flickering. Other electrical issues, such as the power locks, dashboard lights, car radio, and power windows not operating correctly are also signs of a bad alternator. A faulty alternator can also cause your car to stall while driving or have difficulty starting right away. Finally, the car battery may die because it is not getting charged by the alternator.
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Bright Lights That Begin To Dim
With a failing alternator what you will experience is that your dashboard lights will start off brigh and begin to dim after some time.
This happens becuase when you start your car your lights are being powered by your car battery. When you start driving, the alternator is not able to provide the neccessary power to keep your lights bright.
You might experience these issues with your headlights and other lights inside your vehicle as well such as your radio or dashboard.
You can test this by driving you car at night. After starting your car, drive for 10 to 3o minutes to determine if you experience any diming.
Whats An Easy Solution To A Dead Car Battery

Finding a dead car battery under your hood can be pretty stressful, but dont let it get to you.
An easy solution is to call a mechanic to troubleshoot issues or simply attach a new battery.
Fortunately, all you need to do is contact a mobile mechanic like RepairSmith!.
RepairSmith is a convenient mobile vehicle repair and maintenance solution.
Heres why you should opt for them:
- Car battery replacement and repairs can be made right in your driveway
- Expert, ASE-certified technicians execute vehicle inspection and servicing
- Online booking is convenient and easy
- Competitive, upfront pricing
- All maintenance and fixes are conducted with high-quality tools and replacement parts
- RepairSmith offers a 12-month | 12,000-mile warranty for all repairs
Fill this online form for an accurate estimate of the cost of your battery repairs and maintenance.
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Dimming Or Overly Bright Headlights
Your headlights might dim or brighten unevenly and perhaps even flicker. This could mean the vehicles alternator has trouble delivering consistent power.
One way to check is to rev the engine.
If your headlights brighten at a higher RPM, and then dim when you take your foot off the pedal, your car alternator definitely has issues.
Why Does A Dead Battery Hurt The Alternator
To understand why this, happens and why you should not attempt to use the alternator with a dead battery, you have to first understand the working mechanism of an alternator and the physics behind how it recharges the car battery.
This way, you will be able to understand why recharging a dead car battery with the alternator is beyond the alternators engineering and will get it hurt.
Alternators generate the electrical current that recharges the car battery while the engine is running, but how does it do this? a flashback at elementary physics shows that electrical current can be generated from a magnetic field and a magnetic field can be created from channeling current through a wire coil.
The amount of electricity generated by a coil of wire is proportionate to the magnitude of the magnetic field and vice versa.
This principle is central to the working mechanism of the car alternator. The device is composed primarily of b basic parts a rotor which spins to create the magnetic field, the voltage regulator which works synergistically with the rotor by sending current to the rotor to be used in creating the magnetic field.
The stator is the part of the alternator which is excited by the magnetic field generated by the rotor to produce an alternating current.
The last component of the alternator is the bridge rectifier, this will finally convert the alternating current generated by the stator into a direct current.
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What Are The Telltale Signs Of A Bad Alternator
If you suspect the battery is okay and it might be an issue with the alternator, there are some telltale signs to look out for.
- Funny noises. If youre hearing any clicking sounds when you turn on the car or hear a type of growl or high-pitch sound, it could mean the alternator is shot or on its way out.
- Your battery light goes off. Its natural to think if you see your battery light go off that it must be an issue with the battery. But remember, your alternator helps power the battery, so if things are out of whack, this signal could actually mean trouble with your alternator.
- A shift in lights. When your alternator isnt working properly, you might see a change in the interior lights of your car as well as your headlights. They may start to dim and become even darker, or on the other hand, they may be brighter than usual.
- Car accessories arent working properly. If your car radio is on the fritz, or your windows are taking forever to roll down, or any other accessory isnt working as it should. In that case, it could be a sign that your alternator is bad and not providing enough electricity to function properly.
- It smells like something is burning. When your alternator isnt working, it could be burning the rubber drive belt, or there may be hot wires making things smell funny.
Is It A Bad Alternator Or A Bad Battery
Theres this awful moment when you turn the keys in the ignition, or press the start-up button, but the car engine wont start. It doesnt mean that youve got a bad engine, but rather it could be that there isnt enough power to start the car. If you run into this situation, it is usually any one of two that might be letting you down- the battery or the alternator.
But then, how do you identify the culprit without being an expert? After all, you need to know whats causing the problem to help you make the right repairs.
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Bad Alternator Vs Bad Battery
We have all been in situations with our cars when we try to start up the engine, but the car wont start. This doesnt mean the engine is faulty, but rather the battery or the alternator is having problems. But which one is it?
People can easily misdiagnose their power problem by thinking they have a bad battery when they really have a faulty alternator, or vice versa.
So, how can you tell which one is preventing your from starting up your car and how do not make the mistake of replacing the wrong part? Lets look at a few ways that you can tell which components is giving you this problem.
Risks Of Driving With A Bad Alternator
A car can run with a bad alternator, but it means that your battery will support your vehicles power requirements. Since the battery will be using its reservoir energy without charging, it means that you only have limited driving time until the car shuts down. Therefore, you risk getting stranded on the road with a car that cannot power on because of a depleted battery and a dead alternator.
If you wish to prolong your driving distance to get to a mechanic to replace the alternator, turn off all the auxiliary accessories like the air conditioner, internal lights, and radio to save enough power to get to the repair shop.
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Other Symptoms Of A Dead Battery
A dying battery is not an irreversible problem, but having it die on you completely is a hassle. If you want to avoid having a dead car battery, there are some warning signs you can look out for.
- Headlights: if your headlights go dimmer when your car is idling, it is a possible sign of a problem with your car battery. However, it could also be a problem with the alternator. We will cover how to check which it is a little later in the article.
- The Engine: is the engine of your car cranking slowly? While your car might not be starting because of a bad starter motor or an alternative mechanical issue, slow cranking is usually a sign of a dead battery.
- Dashboard lights: if you have a dying or a weak battery, the lights on the dashboard are likely to dim or flicker.
- Battery terminals: check the terminals for corrosion. If you notice corrosion on them, it is a sign of acid leaking from the battery. When you have corrosion on the battery terminals, electricity will not flow properly. Unfortunately, in the case of a corroded battery, you may have to get a replacement battery even if there is still life in the old one because it could be dangerous.
- Check engine light: has the check engine light come on in your car? This is commonly caused by a dead battery or a faulty alternator. When the engine light comes on, check both your battery and your alternator.
- Electrical Systems: if the electrical components in your car are not working, this is likely because of a dead battery.
The Difference Between A Dead Battery And Bad Alternator

When you start having electrical problems with your vehicle, you will notice them rather quickly. You could be driving along on the road and then suddenly see the lights on your dashboard flicker or shut off completely. Soon after, your entire vehicle may stall which forces you to pull over to the side of the road so that you dont get stuck in traffic. This is certainly an inconvenient situation that every driver wants to avoid.
There are two likely reasons as to why you would have these electrical issues. You would either have a dead battery or a bad alternator. It may not always be easy to tell which one youre faced with because the symptoms tend to be similar. After all, the battery and alternator are both responsible for producing electricity. They just produce different amounts of electricity and provide power in different ways.
Contrary to popular belief, the car battery does not supply power to all the electrical components of the vehicle. That is the job of the alternator. However, the alternator cannot start the vehicle because the mechanical energy of the engine is what keeps the alternator running. Therefore, the car battery and starter motor are needed to get the engine running which, in turn, allows the alternator to run.
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