What Can Kill Your Car Battery?

Updated February 21, 2017

Sadly, car batteries are not immortal. For one reason or another, they will eventually die. You can keep the battery on life support by constantly recharging it. This, though, is only a stopgap measure. There will come a time when the battery no longer holds any charge and you'll find yourself stranded. Fear not. By understanding what kills your car battery, you can help prolong its life.


Car batteries are designed to last for approximately four to six years. Old batteries simply will not hold a charge any longer. If your vehicle has an old battery, you'll find that it's not uncommon to have to continuously recharge it. This is due to an inevitable chemical reaction that affects the inner plates of the battery as well as the electrolyte level. As the battery ages, it becomes more susceptible to extreme temperatures, insufficient charging and a simple lack of use. Eventually, time takes its toll and the plates are warped or affected by sulfation. Once the inner plates are coated, the battery is effectively finished, as it will no longer properly hold a charge.

Parasitic Drain

Even when your vehicle isn't running, your battery is working. For example, the time on your radio must be maintained, as well as any antitheft device. The computer on newer vehicles must also have a continuous power feed. What's more, car batteries are often responsible for recharging hand held devices such as cell phones. Last and most serious, a parasitic drain may be caused by a short circuit in your vehicle's electrical system. For example, an exposed wire touching bare metal could cause a drain on your battery. All of these things are capable of killing your car battery.

Bad Connections

The clamps on your battery cables must be securely connected to the battery posts. A loose connection means that your battery won't be able to provide the necessary charge to run your vehicle. More important, a bad connection means that your battery will not be able to receive adequate recharging from your vehicle's alternator. Also, battery posts and terminals that are dirty or corroded can negatively affect the connection. Therefore, examine your battery's connections, ensuring they are tight and clean. Otherwise, your battery will prematurely meet its demise.

Broken Charging System

Your vehicle's alternator plays a huge role in maintaining an adequate charge in your battery. As the car runs, the alternator is continuously working to compensate for the drain put on your battery by ignition and running the vehicle's accessories. If the alternator is malfunctioning, the battery's charge is not replaced. Thus, the battery dies a little more with each and every use. In the end, the battery will completely lose its charge. Although you can recharge it with a battery charger, it will die again unless you have your alternator fixed. Each time the battery is fully drained, its lifespan is shortened.


Weather can have a drastic and deadly effect on your car's battery. Extreme temperatures, both hot and cold, are capable of ruining a battery. First, severe cold slows the chemical reactions that are necessary for your battery to work. Also, cold temperatures thicken motor oil and make it much more difficult for your battery to start the engine. If the battery is allowed to drain completely, it will freeze in temperatures below 0. Extreme heat will also take a severe toll on your car battery. Continuous heat above 37.8 degrees Celsius causes your battery to discharge its energy at a greater rate, thus draining it more quickly. The key to keeping your battery alive in extreme temperatures is to simply keep it fully charged. Even a slightly discharged battery is more liable to die in hot or frigid conditions.

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About the Author

Arthur Barnhouse has written numerous short stories, contributed content to various websites and was an invited speaker at a university symposium on creative writing. He began writing in 2002 and holds a Bachelor of Arts in English literature from the University of Pittsburgh. Barnhouse has driven across the United States numerous times and draws upon his travel experiences in his writing.