Car batteries have a limited lifespan, typically around 3-6 years, but sometimes they fail prematurely due to various factors:

  1. Leaving electrical devices or lights running.
  2. Parasitic drain.
  3. Extreme weather conditions.
  4. Leakage current caused by loose terminals and corrosion.
  5. A faulty alternator.
  6. Short drives that don’t allow the battery to recharge fully.
  7. Self-discharge.

What Causes a Car Battery To Die Quickly ?

Understanding the root causes of factors that lead to battery drain and practicing good battery maintenance can help prevent unexpected overnight battery drain.

1. Leaving Electrical Devices or Lights Running

If your vehicle’s headlights and other accessories, such as the blower fan, interior lights, and trunk light, are left in the “on” position, it can quickly drain your battery.

What you can do about it ?

Many modern vehicles have features that automatically turn off these accessories after a certain period. However, if your car is not equipped with such features, make sure to manually switch off all these accessories before leaving the car to prevent battery drain.

2. Parasitic Drain

What is a Parasitic Draw ?

Even when your car is turned off, the battery still provides power to components like the clock, radio, and alarm system. This continuous draw of power is known as a parasite draw.

What is Acceptable Parasitic Draw ?

Typically, minor draws like those from the clock and radio shouldn’t significantly affect your battery, and these are considered acceptable parasitic draws. However, modern vehicles often have complex systems, including telematics control units (TCUs) that communicate with the manufacturer’s servers for over-the-air updates, primarily related to the drivetrain and infotainment system.

These updates can occasionally put extra strain on your car battery. Additionally, the ability to remotely activate functions like lights and heaters through your smartphone can inadvertently drain the battery if activated unintentionally.

3. Extreme Whether Conditions

Batteries can go flat in extreme hot or cold weather conditions.

In hot summers:

  1. The electrolyte fluid can evaporate, leading to increased pressure that can potentially damage the battery plates.
  2. Additionally, high temperatures can cause components like the alternator voltage regulator and diode to malfunction, resulting in issues such as overcharging or undercharging the battery.

In cold winter:

  1. Cold weather can significantly impact a battery’s performance. When temperatures reach freezing, a battery can lose up to 35% of its performance, and this loss can increase to as much as 50% when temperatures drop even lower.
  2. In cold conditions, the alternator may also take longer to fully charge the battery, further affecting its performance.

What you can do about it ?

To prevent battery drain caused by extreme weather, consider these tips:

Summer: Park in the shade whenever possible to keep your vehicle’s temperature lower.

Winter: If available, park your car indoors to protect it from extreme cold.

4. Leakage Current Caused By Loose Terminals and Corrosion

The buildup of corrosion and moisture on the battery’s surface can create a conductive path between the positive and negative terminals, resulting in a continuous leakage current. Loose terminals and corrosion can also interfere with the battery’s charging process.

What you can do about it ?

To prevent this, regular maintenance and proper cleaning of corrosion from the battery terminals are necessary.

5. Faulty Alternator

An alternator with a faulty voltage regulator can either overcharge or undercharge the battery, leading to deteriorating battery health. Similarly, a faulty diode may not properly convert AC to DC, potentially damaging the battery.

What you can do about it ?

If you notice any signs of a faulty alternator, it’s important to diagnose and address the issue promptly.

6. Short Drive

Battery drain due to short drives that don’t allow the battery to recharge fully is a common issue. Starting a car engine requires a substantial amount of current each time, and to fully charge the battery again, a certain period of charging time is needed. Short drives don’t provide enough time to recharge the battery, leading to the battery’s charge being depleted each time you start the car.

What you can do about it ?

If you frequently take short drives, it’s a good idea to leave your vehicle idle for a while on occasion to allow the alternator to charge the battery fully. Additionally, you can consider using an external battery charger to ensure your battery is adequately charged. This helps maintain a healthy battery despite short trips.

6. Self Discharge

A typical lead-acid battery will naturally discharge at a rate of 0.1 volts per month, even when it’s not in use. Although this may not seem like a significant amount, it can have a substantial impact over time.

To put it in perspective, a fully charged battery reads around 12.72 volts, and it takes approximately eight months of sitting unused for the battery’s voltage to drop to as low as 11.8 volts. At this point, potentially causing it to appear flat..

What you can do about it ?

If your car has been sitting idle for an extended period, it’s a good practice to start the car and let it idle for a while. This helps charge the battery and can also be a part of routine battery maintenance. Additionally, cleaning the battery terminals during this time can ensure a good battery health condition.

What To Do if Car Battery is Drained ?

A dead or drained car battery can indeed be a significant inconvenience. In such situations, understanding how to start a car with a dead battery is essential to get your vehicle moving again.

There are two primary methods to start a car with a dead battery:

  1. Jump Start: Jump-starting a car is an effective method, but it requires caution as any small mistake can potentially cause electrical damage to the vehicle. It’s vital to know how to jump-start a car.
  2. Bump Start: Bump-starting is a less complex method, but it’s worth noting that only manual transmission cars can be started using this technique.


If your car is not starting due to a low or dead battery, you can get it up and running by jump-starting the vehicle. Jump-starting a vehicle is a useful skill, but it must be carried out safely and correctly. Connecting the jumper cables in the right way is crucial for a safe and effective jump-start.

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