Why Do Car Batteries Die?

Car battery

Car batteries die and fail to work for a number of reasons.

If you've driven long enough, you've probably been in the situation where you've gotten into you car, put your key in the ignition, turned in, and the engine fails to start?

You then know the answer right away- the battery is dead.

But why do batteries fail to start? What causes them to go dead?

In this article, we will go over many of the reasons why batteries die and in the process go over ways to prevent this from happening, when possible.

Parasitic Drain

Parisitic drain is what occurs when your car isn't driven for a very long period of time. This occurs because the electrical components in the car, such as the clock and alarm of the car, still consume energy to run. Even though you shut off your engine and leave the car, the clock of the car and the alarm are continuously operating. Even though they only consume very low current to operate, over time, they will consume a lot of the battery's power. Thus, it can leave the battery drain if over a long period of time.

Fix: The way to fix this is, if you know you're not going to drive your car for a long period of time, such as weeks or even months, disable the whole electrical system, including the clock and the alarm system. Park it inside your driveway ( if you have one). Then the battery of the car won't drain slowly over time. Or you can remove the battery from the car and plce it back it when you will use the car again.

Electrical Equipment Left On

If any electrical equipment is left on in a car, such as the lights, including inside the car or headlights, when the engine is not running, the battery can be drained of its charge even in as little as a few hours. This is because when the engine is not running, the energy for the lights and any other electrical components is obtained exclusively from the battery.

Fix: Just make sure that all lights and electrical units are off when leaving your car. Get into the habit of checking once leaving your car. Nowadays, most headlights of cars will shut off automatically once the engine is off after a few seconds. But if you don't have this type of car, get into the habit of checking manually.

Defective Battery

The battery that you put in your car may be defective. Several things can cause a defective battery including low electrolyte levels, an electrolyte leak, or plates that are deteriorating. Even though you put your battery into your car and it has worked for a few road trips doesn't mean it's a good battery. It could have had a leak from the beginning which will then show one day as refusing to start.

Fix: Buy a battery checker to see if the battery is good or not. If the car is not starting, it could be a problem with the car's alternator, not battery. This is why it's good to have equipment to check the battery itself to see if it's the problem.


A battery may die with age. An battery, with time, loses its ability to hold a charge.

Fix: This is why it's recommended that you replace your battery every few years.

Loose, Corroded, or Dirty Battery Temrinal Connections

If cables are loose, corroded, or dirty, they may impede the ability of current to flow to or from the battery.

Fix- Change all cables to ensure that there is a strong and proper connection.

Charging Problem

A problem with the car's alternator will cause battery problems. The alternator is the part of the car which recharges the battery while the car's engine is running. If the alternator is faulty or there is a loose alternator belt, it will interfere with the battery's charging process and prevent the battery from receiving a full charge.

Fix- Either you check or have a mechanic check the car's alternator if you suspect that that is the problem. If it is, your car's alternator either needs to be replaced or fixed.

Extremes of Temperature

Car batteries are made to operate effectively over a wide temperature range, but extremely hot or cold weather can adversely affect them.

Fix- Maybe get a battery which is more resistant to defects during change in temperatures.

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