Should I Replace My Car Battery?

Is your car having trouble starting up? Headlights not as bright as they used to be? Maybe you’ve noticed a bluish-green powder building up around your battery?

These are just some of the signs that your vehicle's battery might need to be replaced. A vehicle battery is exactly what it sounds like: It stores electrical charge for your vehicle to use for its headlights, dashboard lights, starting the ignition, and, basically, everything electrical. Unless you have an electric car, you don't give much thought to charging a battery. When a gas-powered vehicle is running, the alternator converts mechanical energy from the engine into electricity to recharge the battery

But batteries don’t last forever. Over time and thousands of miles, your battery may corrode and become less effective. Eventually, you’ll need to replace your battery entirely. In this article, we’ll explain when you should replace your car battery, as well as a little more about how car batteries work. We’ll also explain how often you should change your car battery.

What is a Car Battery? What Does the Battery Do?

To explain the signs of a car battery dying, we need to understand a bit about how car batteries work and what they are. Unlike AA or AAA batteries, which are dry cell batteries, a car battery is a “wet” battery. This means that inside the car battery, there are lead plates in sulfuric acid. If you’ve ever wondered why car batteries are so heavy, this is why. It’s also why it’s very important to keep a car battery upright: You do not want battery acid spilling -- anywhere.

Car batteries are charged through the alternator of your vehicle, which converts some of the energy that your engine generates into an electrical charge. But if the alternator is charging your battery, why do you need it in the first place? Well, if you want to start the engine, you need a little bit of an electrical charge to get your engine going. Before batteries, this charge was generated by a hand crank. Imagine how inconvenient that would be!

This means that if your vehicle's battery dies, you won’t be able to start it on your own (there are exceptions for hybrid and mild-hybrid vehicles). You’ll need someone else with a functional battery to provide your car with that electrical charge to get you going (also called “jump-starting” a car). So it’s very important to recognize the signs that a car battery is dying so that you don’t get stranded where no one’s around to help. 

Signs of Bad Car Battery

Here are the best ways to spot a dying car battery before it’s too late:

• The battery warning light on your dashboard is on
• You sense a bad, rotten smell (a potential sign that your battery is leaking)
• Bluish-green or white powder around the battery terminals
• A warped battery case, usually bulging on the side or top
• Issues with the headlights, dashboard lights, or other electrical components
• Difficulty starting the engine (including a clicking sound when you turn the key)

It’s possible to replace a car battery yourself, but it’s one of the more difficult forms of DIY car maintenance. Even if you’re not comfortable replacing your battery, if you suspect issues with it, a visual inspection for corrosion or damage is easy to do. 

If you’re wondering how to test a car battery, the easiest way is at an auto shop (many will do it for free), but you can do it yourself. A multimeter, which is a device that attaches to the terminals of your battery to test the voltage of the battery, runs around $10 to $30 for basic models. If it shows 12.6 volts, it means your battery is fully charged; 12.4 or 12.5V is okay; 12.0V is weak and anything under that indicates the battery is dead or dying. 

Car Battery FAQs

How often should I replace my car battery?

Batteries usually need to be replaced every 3 to 5 years. You don’t have to replace a car battery often, but you should replace it as soon as you notice one of the above issues. When to replace a car battery depends on the climate you live in. Areas with very hot, dry climates or very cold winters can put more strain on your battery. You may have to replace your battery sooner if you live in one of these areas. 

While you don’t want to get stranded without a battery charge, you shouldn’t replace your battery unless it’s either dead, about to die or approaching that 3 to 5 year mark. Make sure to test your battery before replacing it. 

Can I replace my vehicle's battery myself?

Yes, you can replace a car battery on your own, but it can be difficult, depending on your vehicle year and make. Replacing a battery especially on newer vehicles isn’t as easy as replacing wiper blades or cabin air filters. There are safety risks like shorting, arcing and damaging electronics. Learn more here. 

How much is a car battery?

A car battery costs around $200, but this will depend on the size, brand, and local pricing. Entry-level batteries can cost $100 to $150, while premium versions can run over $250. If you’re having your car battery replaced at an auto shop, you will also have to pay the mechanic for the labor. 

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