When To Replace Your Car Battery

If your vehicle is having trouble starting, it might be time to replace the battery. There are a few easy ways you can tell when to replace your car battery. It’s something every car owner will likely need to do at some point, even if you take good care of your engine.

Replacing a car battery is a simple DIY repair. We’ll walk you through the steps and tell you how to choose a new one. Read on to learn how you can restore your engine to its full power.

Car Battery Life

Car batteries are rechargeable, but they’re not immortal. The battery’s ability to hold a charge weakens over time. Eventually, even the most durable battery will need to be replaced.

So how long does a car battery last? Most batteries last from 5 to 7 years, on average. A car battery life varies based both on how it’s made and how it’s used. Batteries that regularly sit unused will die faster. If you drive your car every day and never let the battery drain, you could get as much as 10 years out of it.

Signs You Need A New Car Battery

As it weakens, the battery will store and release less power. One of the first signs you need a new car battery is that the lights on your dash will flicker. Some other common indicators that your battery is failing are:

  • Battery warning lamp on your dash illuminates
  • Engine turns over slower than usual when you start the vehicle
  • Power windows move more slowly
  • Lights dim when engine is idling, or brighten when you rev the engine
  • Corrosion on battery terminals and cables

Keep in mind many of these symptoms can also occur with a healthy engine if you’re driving in cold weather. They could also be caused by problems with the alternator, charging system, or wiring around the battery.

To confirm if the battery is the problem, you can test it. Use a battery tester to measure the CCA (cold cranking amps) and compare that number to the battery’s rated CCA. You can buy your own battery tester and do this easily at home. An auto shop can also run an AVR test for around $20 to $50.

If your car’s battery is dead, the symptoms are easy to diagnose: your car won’t start at all. You can easily fix the problem before it reaches this point if you pay attention to how your vehicle drives.

How To Replace Your Car Battery

What you’ll need:

  • New battery
  • Socket set
  • Wrench
  • Battery terminal puller
  1. Loosen the nut securing the negative battery terminal and cable (usually black, marked with a -). Remove them from the post using the terminal puller.
  2. Repeat this process on the positive terminal (marked with a red cover and a +).
  3. Use a socket wrench to remove the clamp holding the battery in place. Set all the parts safely aside where you won’t lose them.
  4. Lift the old battery out.
  5. Position the new battery so the positive post matches the positive terminal’s location.
  6. Carefully install the new battery. Re-attach the clamp holding it in place and remove the plastic caps covering the posts.
  7. Connect the positive post first, tightening until it’s snug. Repeat for the negative terminal.

Battery Selection Tips

Your vehicle’s manual can tell you the recommended specifications for the battery. Pay close attention to this information. Installing the wrong battery can cause short circuits and other damage to your car’s electrical system.

There are a few key details you should pay attention to when you’re battery shopping:

  • Chemistry. There are two broad categories of battery: lead-acid and AGM. Lead-acid batteries are cheaper. AGM batteries hold their charge better and tend to last longer without degrading. Most car engines can use either style, though you should verify this with your car’s manual before shopping.
  • Group number. Automotive batteries used a standardized measurement system known as the group number. This tells you both the dimensions of the battery and its terminal configuration. This will usually be printed on the top or side label of the battery.
  • CCA rating. This tells you how much power the battery provides at 0°F and is a more reliable figure than the CA (cranking amps). Never install a battery with a lower CCA rating than what’s recommended in your manual. This will lead to electrical problems that can damage your engine. A battery with a higher CCA rating won’t damage your car, but it may not last as long, especially in warmer weather.

If you’ve lost your manual or aren’t sure what to look for, remove your old battery and take it with you to the repair shop. A battery that matches its specifications will work in your car safely.

FAQs

Can a dying battery be repaired, or do I just need to replace it?

Battery tenders often have settings that can de-sulfate a damaged battery. In some cases, these devices can even bring a dead battery back to life. Most auto shops also offer battery restoration, though it may be more cost-effective to get a new battery, depending on its age and the cost of the service.

How can I extend the life of my battery?

Driving your car regularly is the best way to avoid battery failure. You can also apply anti-corrosion grease to the battery terminals to prevent deposits and corrosion that stop the battery from charging.

How does the weather affect a battery’s lifespan?

You might think cold is bad for batteries since it makes them harder to start, but extreme heat is actually worse for your battery. In the summer, it can get to over 200°F under the hood of the car. This high heat speeds up the chemical reaction in the battery and speeds its degradation.

The average lifespan for a battery in a hot climate is 3-5 years. You can combat the effects of heat on your battery with a heat shield. Some cars designed for hot weather mount the battery away from the engine to prevent this problem.

Where can I recycle an old car battery?

Many (though not all) auto shops and car dealerships will take old batteries. The Earth911 website has searchable maps in their auto battery recycling guide.

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