Can you drive a car with a bad alternator? (2023)

With a bad alternator, you could bet driving your car. In addition, the alternator provides power to most of the car's electronic components. But can you drive a car with a bad alternator? In general, if the battery is fully charged and working properly, it should run up to 25 miles or about 30 minutes on a bad alternator. If you run out of power, you needpendant with chainor a towing company.

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However, this post covers everything you need to know about driving a car with a bad alternator, the risks or safety measures, and the cost of replacing it.


Can you drive a car with a defective alternator?

Can you drive a car with a bad alternator? (2)

You can drive a car with a bad alternator, but only for a limited time. Depending on how bad your alternator is at the moment, you can drive for up to 30 minutes before it stallscannot be restarted unless skipped.

Se oalternator problemIt's new, your battery probably still has juice, so you might be driving a car with a bad alternator. This is how you simply switch off all non-essential systems in your car while driving. Also, most experts believe you can probably drive your car for up to two hours before it dies.

One important thing to remember is that if you need to start your car while it doesn't have a working alternator, don't turn off the engine once it's started. Starting your car uses a significant amount of energy from your car battery, so there is always a chance that you may not be able to restart your car under these conditions.

How to drive a car with a bad alternator

An alternator is a device thatcharge a car battery. if it failsthe battery discharges quickly. So you generally don't want to drive a car with a bad alternator.

Suppose the alternator fails or has failed. You can probably drive the car a short distance or for a short time, so you can get to a gas station or auto parts store to replace the alternator. Think about the next whileDriving with a defective alternator:

The. Disable assistive material

Switch off any additional devices that are switched on, such as the radio, lights, windshield wipers, air conditioning or heating.

B. Only drive a short distance

Only drive short distances and avoid using electrical systems such as air conditioning, radio or electric windows.

w. Drive carefully in crowded places

Traffic jams can drain the battery. Choose a spot to park until traffic is less intense.

D. do not stop the engine

Leave the engine running when you stop so you can charge the battery.

It is. Contact a mechanic

Finally, head straight to your local gas station or auto parts store and get a new alternator. Install the new alternator yourself or have it done. Before you set off, make sure your battery is fully charged.

Is it safe to drive if the alternator is bad?

It is generally unsafe to drive a car with a bad alternator. The alternator is responsible for supplying power to the vehicle electrical system and charging the battery.

When your car has a bad alternator, it relies solely on the battery to operate its myriad functions, which is why your car's battery drains so quickly without a working alternator.

If your alternator is bad, other problems could endanger you on the road.

  • First, your car's engine becomes extremely unreliable. That can mean not only being difficult to start, but also getting stuck in rush hour traffic.
  • If you drive a car with a bad alternator after dark, you may find that your car's headlights dim significantly, making it harder for you and others to see your car.
  • A bad alternator can also cause the dashboard and other electronics in the car to fail, which is not a pleasant driving experience.
  • Finally, waitburnt rubber smellor other chemical smells emanating from your car. When this occurs, it usually means that the wires are burning or the alternator belts are overheating, both of which are likely reasons for your car's electronics to go haywire.

Does the alternator affect the car battery?

An alternator can affect a car battery. However, it is not necessarily a direct effect. The main function of the alternator is to generate electricity to power the vehicle's electrical systems and charge the battery while the engine is running. If the alternator is not working properly, it may not be able to fully charge the battery, which can result in a dead battery.

However, it is often believed that if one fails, the other will also suffer. While that's true to a degree, it's not as dramatic as it sounds.

In newer cars, a bad alternator doesn't always mean the battery is dead. However, some situations can cause the alternator to damage even a new battery.

When dealing with a bad alternator, here are a few things to look out for.

1. Overload

A bad alternator can overcharge the battery. This can cause premature damage to the battery cells and shorten your car's battery life. It is important to note that prolonged exposure will also damage a new battery.

2. Voltage ripple

Another problem that a bad alternator can cause is voltage ripple. This occurs when AC current flows through the alternator rectifier.

A parasitic ripple voltage can also damage your car's entire electrical system, which can be fatal.

3. Improper loading

While a bad alternator can cause overcharging, it can also cause undercharging.

An insufficient power source for your battery can quickly drain your energy. The constant cycle of undercharging and instantaneously discharging the battery can also shorten its lifespan.

4. Collection of irregularities

Erratic charging occurs when your car's alternator charges the battery in bursts. This makes the power supply unpredictable.

This forces the motor to rely solely on the battery for power. As soon as the battery becomes the main source of electrical energy for the car, it quickly runs out.

Alternator replacement cost

If your car needs a new alternator, you don't have to worry about a repair that will cost thousands of dollars.

In most cases, replacing the alternator is one of the most inexpensive repairs you can do on your car. You should expect to pay anywhere from $100 to $400 to replace your alternator.your mechanic.

Of course, this implies that no additional parts need to be replaced. If you've tried driving for as long as possible with a bad alternator, or no alternator at all, it's always possible that your car has suffered further damage, especially if you notice rubber or chemical odors that indicate wires or belts are burned.

Fortunately, most alternator repairs only require replacing the V-belt. If your car needs a V-belt replacement, it will likely add $25-$50 to the repair price.

Frequently Asked Questions

How long can you drive with a defective alternator?

As long as your car's battery is fully charged, you can drive normally for 25 to 30 minutes. Since the alternator is an important part of the battery power system, it needs to be repaired as soon as possible.

What happens if the alternator is defective?

If the alternator is defective, the battery will drain quickly and the vehicle will die faster. Also, the electrical system can fail, causing problems with the lights, radio, and other electronics.

Will driving with a bad alternator ruin your battery?

Your car can only run for a very short time with a bad alternator becausethe alternator charges the batterywhen the engine is running. Once the battery is discharged, the vehicle dies and will not start.


If you drive a car with a bad alternator, the battery won't last very long, but it should last long enough to take to a mechanic.Failure to repair the faulty alternator can cause a number of problems such as: Regular maintenance and checks are therefore essential.

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Bernhard Juchli

general managerNOBig Dog Garage von Jay Leno

Bernard Juchli is an experienced rider, mechanic and team owner who trusts Avon Tyres.

Bernard is the main driver and the force behind his Big Dog Garage Race Team. He is the general manager and chief mechanic at Jay Leno's shop. Bernard and his team of seven are responsible for all repairs, restoration and manufacturing of Jay's incredible collection of cars and motorcycles.

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How far can a car go with a bad alternator? ›

This is especially true in newer vehicle models. This is because there is more electricity involved compared to an older model. If your alternator is close to the end of its life, you may only make it a few miles down the street before the battery dies or the vehicle begins to exhibit other electrical issues.

What happens when an alternator goes out while driving? ›

What happens when alternator stops working while driving? The car tends to slowly lose power if the alternator has gone bad while the car is being driven. You'll notice the headlights start to dim shortly before the car loses power and dies.

Is it safe to drive with bad alternator? ›

Driving around with a bad alternator isn't a smart idea; as damaged or broken alternators can cause a wide range of problems. They can interfere with your car's electrical features, make it harder to start the engine, and even cause the battery to drain entirely, leaving you with an utterly unresponsive vehicle.

How can I get my car to run with a bad alternator? ›

How To Jumpstart A Car With A Bad Alternator
  1. Find Someone with a Good Battery. You can't jumpstart a dead battery without a fully-charged option at your fingertips. ...
  2. Let It Run. Before the jumpstart begins, you'll want to run the other engine for 3 to 4 minutes. ...
  3. Turn Accessories Off. ...
  4. Get Thee to a Mechanic. ...
  5. Use a Jumper Pack.

How much does it cost to fix an alternator? ›

Alternators can average anywhere from $100 to $350, depending on the model. In most cases, costs will average between $350−400 for the alternator replacement if no other parts need to be changed. Add another $20 to $50 to your bill if the serpentine belt has to be replaced as well.

Do alternators go out suddenly? ›

Alternators can go bad suddenly, or slowly over time. If your alternator is slowly going bad over time there are some warning signs you can look out for.

What are signs that your alternator is out? ›

7 Signs of a Failing Alternator
  • Dim or Overly Bright Lights. ...
  • Dead Battery. ...
  • Slow or Malfunctioning Accessories. ...
  • Trouble Starting or Frequent Stalling. ...
  • Growling or Whining Noises. ...
  • Smell of Burning Rubber or Wires. ...
  • Battery Warning Light on Dash.
Aug 24, 2020

What does alternator problems sound like? ›

If you're hearing a grinding sound in your car, this could indicate that the alternator is going bad. The grinding sound may be caused by a worn-out bearing. Your car can also make a whining sound when the voltage regulator is sending signals to the alternator to charge more than is necessary.

How do I check to see if my alternator is bad? ›

First, open the hood and start the car. While the engine is running, remove the negative cable from the battery. If the vehicle stalls or dies, the alternator is likely bad. This happens because the alternator is not generating enough electricity to keep the engine running on its own.

How quickly can an alternator fail? ›

If you're noticing that your car is having problems starting, you may be wondering just how often do alternators go bad? Alternators can typically last a long time, about seven years or 100,000 to 150,000 miles. But some mechanics report that they are replacing alternators at about 80,000 miles.

Can I charge my battery if my alternator is bad? ›

If the alternator can't charge a discharged battery, it definitely can't bring a dead battery back to life. Some people think that they can just drive around and recharge their battery, but this isn't the case. In most instances, it will only provide a surface charge to the battery, which is pretty much worthless.

Can a bad alternator affect mileage? ›

Alternator Issue

As the alternator is directly connected with the engine, it hampers the driving performance as well as reduces the fuel economy.

How long does an alternator last once it starts going bad? ›

If you're noticing that your car is having problems starting, you may be wondering just how often do alternators go bad? Alternators can typically last a long time, about seven years or 100,000 to 150,000 miles. But some mechanics report that they are replacing alternators at about 80,000 miles.

What are signs of alternator failure? ›

7 Signs of a Failing Alternator
  • Dim or Overly Bright Lights. ...
  • Dead Battery. ...
  • Slow or Malfunctioning Accessories. ...
  • Trouble Starting or Frequent Stalling. ...
  • Growling or Whining Noises. ...
  • Smell of Burning Rubber or Wires. ...
  • Battery Warning Light on Dash.
Aug 24, 2020

How do you tell if it's a dead battery or alternator? ›

Jumpstart your car. If you can turn the engine on, but it dies shortly thereafter, your car alternator likely isn't able to charge the battery. On the other hand, if you jumpstart the car and later on it fails to start on its own, it's likely a dead battery.

What usually fails in an alternator? ›

One of the most common problems you're likely to experience with an alternator is a failure in the bearings. There are needle bearings in the alternator that allow the rotor to freely spin inside the housing, and those bearings can break down over time as a result of exposure to heat and dirt.

What can damage an alternator? ›

There are several issues that can ruin an alternator:
  • Using jumper cables wrong,
  • Overloading the charging system with too many accessories,
  • Leaking fluid, or.
  • A tight belt that can damage bearings.
Jul 26, 2021

Can AutoZone test your alternator? ›


Testing will ensure you identify a power issue correctly. How to get your alternator tested: Just visit a nearby AutoZone. We'll test the alternator while it's still in the vehicle.

How do I know if I need a new alternator? ›

The most important sign which indicates you need a new alternator is your car's ability to start up. If you have a hard time starting it or can't at all, your alternator has ties to these problems. Engine issues also have ties to this issue which could spell trouble all around.

Do you have to replace battery when replacing alternator? ›

Check the Battery

Your battery should be one of the first things on your checklist after installing a new car alternator. Any installation guide will say that you need to disconnect the battery before installing the new alternator. So, at the very least, you need to make sure that you reconnect it.


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