How Long Do Car Batteries Last?

Close up of auto mechanic jumping battery car
If you have you jump start your car battery multiple times, it's likely time for a replacement battery. Ratchaneeyakorn Suwankhachasit / Getty Images

All-electric vehicles are becoming increasingly popular, so it’s easy to forget that old fashioned, gas-powered cars and trucks are still reliant on electric batteries for their operation. Easy to forget, that is, until those batteries die, either permanently or temporarily. So, it’s only natural to ask: How long do car batteries last?

The answer to this question depends on several factors, such as battery age, climate where the battery is stored and the driving habits of the car owner. While some generalizations can be made about average lifespan, no two batteries will perform exactly the same.

To get the most out of your car battery, whether it is old or new, it’s helpful to understand how different variables will affect your car battery’s life. This can lead to significant improvements in the overall lifespan, as well as better performance.

How Do Car Batteries Work?

Most modern gasoline and diesel vehicles use lead-acid batteries. Inside the battery is a series of cells containing lead plates, which are submerged in a solution of sulfuric acid that serves as the electrolyte.

When activated, a chemical reaction occurs, creating a current of electricity. These relatively sturdy, reliable and cost-effective devices are called wet-cell batteries, or flooded lead-acid batteries (FLA for short). They remain the industry standard.

When you turn the key in your ignition, the car battery sends a strong, brief jolt of electricity to the starter motor. This allows the internal combustion engine to begin operating. The alternator, an electric generator powered by the now-firing engine, sends electricity back into the battery, recharging it while you drive.

What Other Types of Batteries Are There?

In addition to the standard lead-acid flooded battery, there are other options on the market. Some of these have advantages over the standard FLA batteries.

  • Sealed lead acid batteries: These batteries have sealed cells, which makes them especially resistant to spillage. Often used in recreational vehicles, they can withstand the extra vibration and overall movement that such vehicles encounter.

  • Lithium-ion batteries: Lithium batteries are most commonly found in hybrid and full-electric cars, as they must discharge a lot of power over long periods. They are more expensive, but will last from eight to 20 years.

  • Absorbent glass mat batteries: This battery type (also called AGM for short) uses a solid electrolyte, rather than a liquid electrolyte. AGM batteries can better withstand a deep discharge and generally have a better lifespan than lead-acid batteries — up to seven years or longer.

What Is the Average Lifespan of a Car Battery?

The average car battery life is about three to five years. Some batteries can last significantly longer, however, if they are treated well and kept in a relatively stable environment.

Many batteries sold today will include a three-year or 36-month warranty, although some will have warranties lasting significantly longer, such as 80 months.

While it can be worth it to pay for the battery with a longer warranty, with the right care, you can increase your chances of getting your car’s battery to live longer, and perform better, before having to replace it.

What Shortens Car Battery Life?

The lifespan of a car battery is determined by several factors. The four most important elements in knowing when to replace a car battery are time, usage, temperature and vibration.

1. Time

This refers not just to the age of the battery, but also how much time it spends powering the car. All batteries will degrade with age, but sitting inert for long periods will significantly diminish their lifespan.

When the car is operated regularly, it keeps the charge full and prevents the battery from going completely dead, which ensures that the battery is working optimally.

2. Usage

Running the air conditioning, radio, or lights while the car engine is switched off creates a strain on the battery. What’s more, modern cars tend to have a lot of extra electronics, all of which draw power.

If the engine isn’t running enough to fully charge the battery each time it’s being used, this can lead to battery degradation over time.

3. Temperature

Excessive heat can degrade the battery, leading to a shorter battery life and poorer overall quality. However, too much cold isn’t good either; it will create more of a burden for your battery when it comes time to start the car, and it can also lead to faster discharge.

4. Vibration

Too much vibration isn’t good for a car battery, since the agitation of the internal components can cause corrosion and gradual decay.

How Do I Know When My Car Needs a New Battery?

When you have a truly dead battery, you’ll know it right away, because the engine won’t turn over. However, the signs that a car battery is nearing the end are often less blatant. By paying attention to your car battery’s performance, you can get a good idea of when it will need to be replaced.

  • Sluggish or intermittent starting: If you haven’t changed your car use patterns but your car is suddenly struggling to start, it’s a sign that your battery might be in need of replacement. Listen for a slower, lower chugging sound, which indicates less charge in the battery.

  • Dim lights: If you notice that your headlights seem less bright, it could be a sign that your car battery is nearing the end of its lifespan.

  • Foul odor: When a vehicle’s battery is starting to die, it can start to give off an unpleasant smell, similar to rotten eggs. This is hydrogen sulfide gas, and it means you should get your battery looked at — and likely replaced — immediately.

  • Corrosion: When you open the hood, your battery should be visible. Check the battery terminals, which are the points at which the battery is connected to the wires that send electricity to the rest of the car. If there’s a white, mineral-like buildup, it could be a sign of corrosion and degradation of the battery.

What Are Some Ways to Extend Car Battery Life?

If you want to keep your car battery healthy, and maximize the time before you have to shell out for a replacement, there are some reliable methods to do so. Using even one of these guidelines will help, but for the best results, it’s helpful to use them all.

1. Limit Short Drives

Short trips can put additional strain on your battery, because they don’t offer the chance for a sustained charge.

Once the car is started, the alternator charges the battery, but it takes time and elevated RPMs (revolutions per minute) to get the job done. On shorter trips, the battery doesn't get adequate time to fully charge.

2. Control the Temperature

If you can, keep the temperature of your vehicle stable (which in turn will keep your engine compartment, and thus your car battery temperature, stable).

This is most easily accomplished with a garage where you can keep the car out of the hot weather. Even if you don’t have a garage, parking in the shade wherever possible will still help.

3. Clean Off Corrosion

Every so often, take a look at your car battery terminals. If there’s corrosion visible, give it a clean. Always use protective gear: rubber gloves, an apron and eye protection are worthwhile precautions.

Remove the battery from the car, and scrub the terminals with a wire brush. You can purchase battery contact cleaner from your local auto supply store, or you can use a solution of warm water and baking soda.

4. Use a Battery Maintainer

These small electronic gadgets are often affordable and easily stored, either in your garage or in the trunk of your car. When plugged into a standard outlet, they provide a slow trickle of electricity to the battery, ensuring it has optimal charge at all times, and switching off when the optimal level has been reached.

Some devices will also include a charging function to bring a depleted battery up to full charge quickly.

Can My Car Battery Last 10 Years?

A well cared-for car battery can indeed last 10 years. While most batteries won’t make it to the decade mark, it does happen. If you’re always keeping your battery charged, protecting it from temperature extremes, excess vibration and corrosion, you’d be surprised at how many years your battery will last.

Original article: How Long Do Car Batteries Last?

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