How Long Will a Battery Last With a Bad Alternator?

An alternator is among the best machines in a vehicle. This is because the ignition system of a vehicle fully depends on the alternator for it to work. If an alternator does not work, a continuous charge will not be supplied to the battery, and thus, energy will not be replaced after use. In simpler terms, once the alternator is damaged, the vehicle’s battery will not be recharged as you drive, and eventually, the vehicle will stop.

How long the battery lasts depends on some different reasons though there is always an average time depending on the type of battery you are using. If an alternator gets damaged, this is not always the end of your driving journey, as there are some simple hacks on how to handle such conditions. This article will help you know how long a battery can last and what to do if such happens.

Factors affecting the time a battery lasts with a damaged alternatorHow Long Will A Battery Last With A Bad Alternator

The various factors include;

  • The type of engine being used.
  • The make of your car- If the car is outdated, it will take a short time as its system is not digitized, but if the car is modern, it might last for some time.
  • The number of electronics in your car- In this case, a car with lesser electronic systems will tend to last for more hours compared to the one with more electronic systems.
  • The time of the day in which the alternator has stopped. If the alternator stops at night, more energy will be needed, such as when using the headlights. During day time, less energy will be used as things like headlights are not needed.

Estimating the time a battery can last without an alternator is somehow challenging as many factors have to be considered.

A damaged alternator on different carsA damaged alternator on different cars

1. The classic diesel car

Diesel cars have much simpler engineering that can be easily figured out. In such cars, the engine probably drives the fuel pump without any spark plugs. In some other way, the engine will also drive the hydraulic pump to help in steering. Theoretically, diesel engines may run until the fuel is finished. When using a diesel car and the alternator is damaged, then you will not be able to access any electronic system in your car, so the battery lasts longer.

2. The Gasoline-powered car

There is a great difference between a car that uses diesel and one that uses petrol. In this type of car, there are spark plugs that usually drain the battery. In addition, it contains an engine management system that drains power off. On the other hand, a gasoline-powered car contains airbags, ABS systems, and some other system that uses a lot of power. Minimally, the battery can last up to 30 minutes and maximally to almost two hours.

  • In cases where you start your car without having an alternator, do not try turning off the engine on your way. Starting the car engine flattens the car battery fast. Headlights follow, starting the engine and draining the battery. It would be best if you always were cautious enough to handle these occurrences. You should never turn them on unless it is the only alternative left.

Signs of a bad batterySigns of a bad battery

If a car takes more time to start than it normally does, it could be due to a low charge or a click after turning on the ignition key, and this shows that the battery has no charge and action needs to be taken. In cases where the battery does not charge at all, there could be some minor issues. These issues may include;

  • Posts might be corroded. Ensure that the battery posts are in good condition. With this, it could be a loose connection, corrosion, or even they could have been worn out. You need to clean the posts and tightly reconnect them.
  • The battery could not be holding charge. Such may occur mostly if your battery has served for a long period could be four to five years. In such a case, you need to charge the battery by using a high-maintenance charger. Then, if the problem remains, you need to replace your battery.

Signs of a bad alternatorSigns of a bad alternator

The first sign of a bad alternator is a warning light on the dashboard of your car. Other indicators also show that the alternator is damaged. Some of the signs include;

  • In circumstances where the car starts with ease, but a warning light still shows up immediately. If this occurs, it is probably that your alternator is damaged or it is not working effectively.
  • If your car is modernized, it will just shut some equipment.,For example, the airbag, air conditioner, and ABS systems. When these systems go off, and the warning light shows, then consider checking your alternator.
  • The headlights may appear dim when you are driving at night. In cases of dim headlights, you should first suspect the alternator.
  • If dashboard lights flickering or the speedometer stops working, the problem could be with the alternator.

Causes of a bad alternatorCauses of a bad alternator

An alternator can fail due to some very petty issues. For instance, dirt or dust particles or even failure of some bearings. These causes could be;

  • When the alternator belt is overtight.-an overtight alternator belt will ruin the alternator’s bearing, making it fail.
  • The presence of dust, dirt, or oil in the windings.-Such will hinder the alternator from working to its optimum level.

Tips for you to drive longer with a bad alternatorTips for you to drive longer with a bad alternator

  1. When starting your car, use a different car battery or any jump-start booster
  2. Avoid using lights, radios, fans, power windows, or any system using electricity when driving.
  3. Always make sure to fully charge your battery using a trickle charger as many times as possible.
  4. Check on your speed. If you drive faster, you can cover a longer distance though you should not break the speed limits.
  5. Set all the bulbs to LED to consume less electricity.

An alternator can last for about five to ten years before damage when well maintained. When fixing the alternator, it can take about one hour to three hours depending on the car model and depending on how well the one fixing it can do it. If the alternator is damaged, you can carry more charged batteries and keep changing when one flattens if you are unable to replace the alternator immediately.


In cases where the alternator is damaged, it is advisable to replace it within the shortest time possible as it can also damage the car battery. If you cannot replace it with immediate effect, follow the above tips or use different car batteries to avoid overusing one car battery without supplying energy into it. If the car alternator gets damaged, it is advisable to reduce traveling and wait until it is replaced.

In circumstances where you are unable to replace the alternator yourself, do not try fixing connections that you are unsure about. It is always best to contact a professional to avoid causing other major problems to your car battery or other electronic systems in your car. Always take precautions when handling any electric appliance. When the alternator or the battery functions for a long period, always replace it before it starts malfunctioning.

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