How Long Will a Car Run without an Alternator?


The alternator converts mechanical energy from the engine into electrical energy, which powers the vehicle’s electrical components and accessories and keeps the battery charged.

A car without an alternator can only travel as far as the battery can power it, which is typically around 25 miles or 40 kilometers. The vehicle’s range will most likely be limited to 2 or 3 miles.

Consequently, the battery will not have enough charge to power the vehicle’s electrical components, causing the car to stall.

If your alternator fails, you will definitely be stranded, so if you’re driving and you notice it isn’t working properly, pull over to a secure place as soon as possible.

How Far Can I Drive My Car with a Dead Alternator?

If the alternator is dead, your car will need to draw power from the battery. On a full battery, it should be possible to drive the car for up to 25 miles, depending on the quality and size of the battery.

The alternator in your car converts mechanical energy into utilizable electric energy in the form of alternating current and is responsible for keeping your vehicle’s battery charged.

The fully charged battery powers the vehicle’s starter, which spins the engine for the first few rotations before combustion occurs.

This charging system supplies energy to the battery, which manages several critical operations that allow your vehicle’s electrical components to function.

The battery not only powers the vehicle’s ignition system but also controls other components such as the lights, headlights, radio, ignition, drive belt, and power windows—the battery even controls your heated seats.

Less battery life means less travel time when the alternator fails. The car will not start if the battery cannot supply alternating current to the engine. If your alternator fails, you may notice the following symptoms:

  • Stalling or starting difficulty
  • A damaged belt
  • Burning smell
  • The alternator warning light
  • Bright or dim lights
  • Whining noises.

These problems can sometimes occur as a result of other issues in your vehicle.

If you experience more than one of these issues, your alternator could be faulty.

Most cars have an alternator that will last between 80,000—100,000 miles before it needs to be repaired or replaced.

Can I Drive If the Alternator Is Not Working?

You can drive a few miles with a faulty alternator, but it is dangerous.

A nonfunctioning alternator will almost certainly leave you stranded.

When the alternator fails, and the battery starts to drain, your headlights and dash lights will begin to flicker.

When the battery dies, nothing powers the vehicle’s electrical systems and the vehicle stalls. However, the battery light will most likely turn on before this occurs, inferring that the car’s electrical systems are about to shut down.

As soon as you suspect a problem, have a professional mechanic inspect the car’s alternator. Checking a battery and alternator is a simple procedure that should not take long or be expensive.

The mechanic will advise you on the next steps to take; however, replacing the alternator rather than repairing it is usually the most cost-effective option.

How Long Can a Car Battery Last If the Alternator Is Dead?

The battery’s age, size, and quality determine how long a car will last with a damaged alternator.

It will probably be a few minutes before you notice the battery dying, so get your vehicle parked at a safe location as soon as possible.

Modern vehicles have a sensor that will alert you if the alternator is not generating enough voltage, which is a sure sign that you should take it to the auto repair shop immediately.

When you see this warning sign, check for electrical faults such as dimming, flickering lights, or other faulty electrical systems.

The alternator is responsible for supplying power to the battery in these systems. If your alternator fails, your vehicle’s battery will struggle, and these electrical functions will fail.

How Far Can You Drive on a Full Battery when the alternator is dead?

If your battery is fully charged, you can drive up to 25 miles without an alternator, but this is highly dependent on the type of vehicle and battery. As a result, you should only expect to travel 2 – 3 miles before encountering difficulties.

If you suspect an alternator problem, take your vehicle to a auto repair shop for diagnostic testing as soon as possible.

It is better to detect alternator problems in your vehicle before they become a hazard on the road.


A car with a faulty alternator is unsafe to drive.

If you can start the car with a bad alternator, you won’t get very far before the battery fails and the car stalls, leaving you stranded.

The maximum distance you can expect to travel without an alternator is 25 miles; however, it is much more likely that you will only travel 2 – 3 miles before the vehicle’s electrical system begins to malfunction and the car dies.