Your vehicle relies on the battery under the hood for everything. And we mean everything. From running your radio to starting your engine, the battery is crucial to your vehicle’s operation. And although batteries have seen great advancements in the last few decades, they are still prone to failure and various malfunctions.

But why do car batteries fail? The answer to this popular question includes many different reasons, including age, corrosion, alternator problems, extreme weather conditions, or the classic case of headlights being left on. Christian Brothers Automotive is here to explain why these common problems affect your vehicle’s battery.

Common Reasons Why Car Batteries Die

As mentioned, several factors can cause your car battery to fail unexpectedly. While some causes like age and weather are unavoidable, others stem from common driving habits or maintenance oversights. Let's dive into the specific reasons your battery might leave you stranded:

Old Battery

On average, car batteries last anywhere from 3 to 5 years. The older your battery is, the more likely it is to malfunction and leave you without power. As batteries age, their internal components naturally deteriorate, reducing their ability to hold a charge effectively. Even with proper maintenance, time eventually takes its toll on every battery's performance and reliability.

Corrosion

Due to the constant use and contact of the metal terminals on your battery, they will oxidize and corrode after a while, causing them to wear out. This weakens the connection between your battery and the electrical system.

Your battery won't be able to supply as much power and will age more quickly due to the increased resistance between the battery terminal and electrical lead. Corrosion typically appears as a white, blue, or greenish powdery substance around the terminals and can significantly impact your vehicle's electrical performance.

Alternator Problems

Your battery is not a continual supply that runs out slowly over time. It relies on your car's alternator, which helps recharge it after use. When working properly, the alternator takes the energy your engine produces and turns it into electricity using a generator that feeds back into your battery.

When your alternator stops working properly, your battery will not be able to charge and will die quickly and often. Signs of alternator failure include dimming headlights, dashboard warning lights, and unusual noises coming from under the hood.

Extreme Weather Conditions

Batteries are designed to work best in a comfortable, moderate temperature range. This means that hot and cold temperatures can cause severe strain on batteries. If the battery is exposed to severe cold temperatures, the electricity cannot pass through the system as easily, making it tough to output enough voltage to start your car until the battery is back to the optimal temperature. If it's too hot, the battery wears out more quickly.

Just like the other fluids in your car, the essential fluids in your battery can easily evaporate if the temperature outside is hot enough. Additionally, the corrosion process speeds up in hotter conditions and is even worse when your battery is low on fluids.

Leaving Lights On

Your headlights use considerable battery power, which is a current your battery can only sustain for a short period. When lights are left on for extended periods while the engine is off, they can completely drain your battery's stored energy. This problem isn't limited to just headlights—interior lights, radio, and other electrical accessories can also cause battery drain if left running without the alternator replenishing the power supply.

Why Do Car Batteries Die Slowly?

Modern batteries are made to be extremely strong. They provide a lot of turnover power, even in the cold, up until they are no longer capable of working – which is great news! But, even with this, it’s important to ask: Can a car battery just die without warning? Absolutely.

In the past, when your battery was weakening, you would have plenty of warning. You’d crank the key, and your car would turn slower and slower before finally firing. This allowed you to get a new battery before it stopped running completely. Unfortunately, because today’s modern batteries run strong, they run right until they give out—which doesn’t give drivers proper warning signs before dying.

If you’re worried that your battery is nearing the end of its life, try these at-home diagnostic tests to be sure:

1. Listen carefully to your engine as it turns over every morning. If the crank sounds different or slower than usual, your battery may be about to die.
2. Attempt to turn on your car’s accessory mode and operate your windows (or another high-power feature). If your windows move sluggishly, a dead battery may be in your immediate future.

By staying alert to these subtle warning signs and understanding the factors that contribute to battery failure, you can better prepare for battery replacement and avoid the inconvenience of an unexpected breakdown.

Visit Christian Brothers Automotive for Reliable Battery Services

If you're noticing any of these battery warning signs, don't worry—our friendly, ASE-certified technicians take joy in providing reliable battery service that keeps your vehicle running smoothly and gets you back on the road safely.

Christian Brothers Automotive is locally owned and operated in communities across the country, offering upfront, honest advice and practical solutions for all your battery service needs. Whether you need a new car battery or preventative maintenance, we're here for you when you need us—because that's what good neighbors do.

Need battery services? Find your local Christian Brothers Automotive today!