Will a Car Start with A Bad Alternator?

There are several a number of components in a car’s electrical system including the alternator, starter, wiring, and battery any of which can affect a car’s ability to start properly or at all.

Some are more contributory or indirect in contributory in nature to the failure whereas others like the starter, wiring, and battery tend to have a more direct impact on the car’s ability to start.

So in this post, I cover:

  • Whether a car can start even when it has a bad alternator
  • Signs that the alternator is the reason for your car failing to start
  • whether you can jump start a car with a bad alternator and

lastly, what else can cause your car to fail to start.

Will a Car Start with a Bad Alternator?

Short answer, sometimes but not always. A car with a bad alternator may be able to start, though It is not always the case that it will start given the variations in delay and extent that negative impact a bad alternator can have on the car’s battery system.

The health of a battery is one of the key components that determine whether the car will start.

A bad alternator can drain the battery flat, damage it resulting in the car failing to start.

Or, it may only intermittently charge the battery, partially charge it so the car may be able to start when the battery has sufficient charge and fail to start when it is low.

Can You Start a Car with A Bad Alternator?

yes, you may be able to start your car if it has a bad alternator depending on the extent of the negative impact it has had on the battery, provided that the rest of the car’s electrical system – starter, fuses, wiring work well.

Your car can still face performance problems as you drive from not having a working alternator -the battery not charging properly and the electrical accessories in the car working intermittently because the alternator is not able to supply enough power.

The car may also fail to start eventually because of the low battery charge caused by the alternator not being able to charge the battery properly.

Related topics: signs of a bad alternator; what does a bad alternator cause? What other problems can a bad alternator cause?

Signs that a Bad Alternator is causing Car Starting problems

As mentioned, though the impact of the car failing to start because of a bad alternator may not be direct or may be delayed, these are some of the common signs that can point to a bad alternator.

Note: They themselves are not confirmatory. You may need to conduct additional tests that you have a bad alternator.

The car’s headlights dim when the car’s engine is idling. If the car has a failing alternator, it may not be able to supply enough power to the car’s electrical system and to charge the battery.

So, with the headlights switched on and lack of enough power from the alternator, the car then relies on the limited power from the battery which drains over time, dimming the lights.

Battery voltage reading outside the range 13.7 – 14.7V with the car engine running. A Lower reading can point to an alternator not producing enough power and likely undercharging the battery.

A much higher reading may be a sign of a regulator problem with the alternator that causes overcharging of the battery and frequent failure of the batteries.

The battery light comes ON during driving.

This is usually a sign of a problem with the car’s charging system and whereas there a several possible causes including bad connections, bad battery, it is also possible the culprit is the alternator.

Following the light coming on, you may experience a flat battery that needs to be jumpstarted.

You may be able to narrow down the problem to the alternator if you successfully rule out the battery and confirm that the battery can hold charge for several hours after being fully charged without the electrical accessories switched on.

You can also have your battery and alternator tested at an Autozone.

Can You Fix Bad Alternator Problems that May Be Stopping Your Car from Starting?

In some cases, you may need to replace the alternator while in others, the problem might be easier to fix than you think. here are some areas you can look at:

  • Loose connector plug in connecting to the alternator.
  • Poor alternator ground connection
  • Loose, worn, or slipping serpentine belt.

Related questions

Can You Jump Start a Car with A Bad Alternator?

Yes, you can still successfully jump start your car even if it has a bad alternator.

This is because the alternator itself does not play a direct role in the starting of the car.

It is responsible for generating the electric power that the car electrical accessories use, to charge and maintain the battery charge as the car engine runs.

For information on how to properly jump-start your car (options) for jumpstarting, check out this article.

What Else Can Cause Car Starting Problems?

Beyond the problems caused by a bad alternator that can affect your car’s ability to start, the are other issues that you can explore if your car is not able to start.

  • damaged or dead battery
  • burnt out car fuses
  • Loose or bad battery connections including the grounding
  • Faulty ignition switch
  • Faulty starter
  • mechanical problem with the engine

To summarize, a car with a bad alternator may be able to start but not always.

The effects of the alternator on the car’s starting sequence affect the battery charge and are not always immediate and severe in nature.

In cases when the car is not able to start, you may be able to tell this from conducting basic alternator tests such as switching on the headlights while the engine is idling and checking for dimming.

You can also measure the car battery voltage with the engine running for an indication of whether the alternator is supplying the expected battery voltage to the battery.

Also, the car battery light coming on as you drive may be caused by a faulty alternator.

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