When to replace a car battery?  |  Testing Autos (2022)

Updated: July 16, 2022

The 12-volt battery in your car stores the electric power to start your engine. When the engine is started, the alternator generates the electric power and recharges the battery.

Car battery.

A new battery has a full capacity or ability to hold charge. It can store enough electric charge to turn over your engine multiple times and power the electrical systems when the car is parked. Over time, however, the battery loses its capacity and becomes weak.

One day, a weak battery will not be able to start your car. Often, this happens on a cold morning. When to replace the battery? The battery need to be replaced before its capacity drops to a critical level.

How long do car batteries last?

On average, a car battery lasts from 5 to 7 years. The battery lasts longer if the vehicle is driven daily and the battery is kept fully charged. When the vehicle is parked for extended periods of time, the battery deteriorates sooner. The size of the battery matters too: larger batteries last longer. We have seen larger batteries lasting up to 10 years.

How can you tell that the battery capacity is getting low?

When the battery's capacity becomes low, you might notice that at times, the engine turns over slower, not as eagerly as before. The dash lights may flicker when starting the vehicle. Another sign is when you operate your power windows after the engine is turned off, the windows move much slower than when the engine is running. Your vehicle might also need frequent boosting.

(Video) How to Test and Replace a Bad Car Battery (COMPLETE Ultimate Guide)

Sometimes you also may notice that the lights turn dimmer when the engine is idling, but become brighter again when the engine is revved. The excessive corrosion at the battery terminals and cables (see the photo) also suggests that the battery is getting weaker.

Can the battery capacity be tested?

Testing the battery capacity with a battery tester.

Yes, the battery capacity is often measured in CCA or Cold Cranking Amps. A new average-size battery like the one in the top photo is typically rated between 520 and 650 CCA.

Many automotive repair shops can test your battery with a battery tester (in the photo). The battery tester can measure the actual CCA and compare it to the new battery CCA rating. The battery CCA rating is marked on the battery itself, see the photo.

The battery tester can also test the alternator and the charging system. Read more about the charging system: When does the alternator need to be replaced?

Battery and charging system test printout

The battery and charging system test, known as the AVR test, costs from $20 to $50. Some auto parts stores such as Autozone or O'Reilly Auto Parts offer a battery test at no charge. Many car dealers and repair shops often offer a free battery test as a part of a larger service or a seasonal promotion.

(Video) When Should You Replace Your Vehicle's Battery?

After the test, you might get a printout showing the battery CCA rating and the measured CCA. The printout will indicate if the battery should be replaced or if it's in good condition. The printout may also indicate that the battery needs to be recharged first and then re-tested. See the sample printout in the photo.

Can you test a battery with a voltmeter?

Testing the battery state of charge with a voltmeter.

The battery voltage is an indicator of the state of charge of the battery. A fully charged battery should read 12.6 volts or more with the engine off. However, even an old failing battery with low capacity will show 12.6 volts when fully charged.

To test the capacity of the battery, the battery voltage needs to be tested under load. The longer the battery can hold the voltage under load, the larger its capacity.

For example, if the fully-charged battery voltage with the engine OFF and headlights ON drops from 12.6 volts to less than 11.5 volts in a couple of minutes, the battery's capacity is low. If the battery voltage with engine OFF and headlights ON stays close to 12 volts even after 10 minutes, the battery is good.

Can a problem with battery terminals cause the vehicle not to start?

Corroded vs. serviced battery terminal.

Yes. If one of the battery terminals is loose or corroded, it may cause many problems including a no-start, Check Engine light, stalling, as well as lack of the electric power steering assist. Many dealers and reputable repair shops visually inspect the battery terminals during regular oil changes.

(Video) How to Test a Car Battery with a Multimeter

Your mechanic may recommend servicing battery terminals if they are corroded as in the photo. The battery terminal service costs from $25 to $50. It includes cleaning the battery posts and terminals and applying a protective spray or grease.

How much does the battery replacement cost?

A new car battery costs from $140 to $550 and your dealer may charge another $30-$50 to have it replaced. Replacing a car battery as a do-it-yourself project is not very difficult, but the battery is heavy (30-45 lb). Lifting it out of the car can be hard on your back. An old battery is often covered in electrolyte, which is very acidic and can burn your clothes or skin. Here is a video from O'Reilly Auto Parts.

Our recommendation is to leave it to the pros. Some cars require a specific battery type. To make sure, check the vehicle owner's manual or consult with your local dealer.

What is an AGM or Absorbed Glass Mat battery?

AGM Battery.

An AGM battery is a modification of a traditional lead acid battery. In a traditional lead acid battery, cells are filled with liquid electrolyte. In an AGM battery, the fiber glass mats soaked in electrolyte are sandwiched between the lead plates. So the main difference is that in an AGM battery the electrolyte is not free-flowing but rather contained in the absorbed glass mats like in a soaked sponge. AGM batteries are supposed to be more durable, resistant to vibration and hold the charge longer when not in use, however they are also more expensive and more sensitive to overcharging.

Are AGM batteries really worth it?

If your car has a Start-Stop system it might require an AGM battery. Many motorcycle, ATV and RV owners prefer AGM batteries for their performance and durability. However, if your car doesn't require an AGM battery, a traditional acid battery of the right type is more suitable. AGM batteries don't like overcharging and if the vehicle is not designed for an AGM battery, this could be a problem on a long trip, especially in hot weather. Check your owner's manual for the correct battery type.

Where to recycle an old car battery?

Some automotive repair shops and car dealers will accept your old battery for recycling. For example, you can find the nearest place to recycle your old battery at the Interstate Batteries website.

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How long is the battery warranty?

In most cars, the battery is covered under the basic bumper-to-bumper warranty. In some cars, the battery coverage is pro-rated. This means, for example, the labor might be fully covered, while the part might be covered 100 percent within the first year, 50 percent within the second year and so on. You can find the warranty coverage details in your Warranty Guide brochure, or on the manufacturer's website.

How to boost a car when the battery is low on charge?

To boost a car, you will need a portable booster or jumper cables to boost from another car. Your owner's manual has the proper instructions. Be careful, if the booster cables are connected to wrong terminals, it may cause a big spark and some fuses and other electrical components could be fried.

How long does it take to recharge a good battery that is low on charge?

If the battery is still good, 20-40 minutes of running the engine or driving is usually enough to recharge it.

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However, be aware that in some cars with electric power steering, the steering assist might not work properly until the battery is sufficiently charged. This can make driving with a low battery dangerous.
If a good battery has not been used for an extended period of time and is completely drained, it might need longer time to recharge.

In some high-mileage cars, the engine may run rough at idle or even stall after replacing the battery. This happens because when the battery is disconnected, all learned settings in the engine computer, including the idle speed, are reset. For this reason, some older cars may require the idle speed re-learn after the battery is replaced. The procedure varies for different cars, but it won't take you long to google it. To avoid this problem, many repair shops use a simple memory saving device that keeps the engine computer powered during battery replacement. In modern cars, the idle speed is re-learned as you drive.

(Video) How To: Install a Battery in Your Vehicle

Read Next:
When does the alternator need to be replaced?
When does the starter motor need to be replaced?
How often does a car need a tune-up?
When should you change your automatic transmission fluid?
How often do brakes need to be serviced?
How To Save Money on Car Repairs - Mechanic's Tips

FAQs

How do I know when my car battery needs replacing? ›

5 Signs Your Car Needs a New Battery
  1. Your Battery Is 3 Years Old. The average lifespan of a car battery in Alberta is 3-5 years. ...
  2. Your Headlights Dim and Your Heater Motor Slows. ...
  3. You've Needed a Lot of Boosts Lately. ...
  4. Your Engine Takes Its Time Turning Over. ...
  5. Your Car Doesn't Start at All.

How often should you get your car battery tested? ›

Typically, it's recommended that the battery be inspected at least twice per year (every 6 months or 6,000 miles).

At what voltage should a car battery be replaced? ›

If the measured reading is less than 12.2 volts, the battery's resting voltage is weak, which means it most likely needs to be charged or replaced.

When testing a car battery what should it read? ›

Check the reading. A fully charged battery will typically display a voltmeter reading of about 12.6 to 12.8 volts. If your voltmeter is showing a voltage anywhere between 12.4 and 12.8, that means your battery is in good shape. Any voltage above 12.9 volts is a good indicator that your battery has excessive voltage.

What is the average life of a car battery? ›

Some cars will get up to five or six years out of their battery, while others will need a new one after only two years. In general, your car will usually need a new battery after three to four years. Replacing your car battery is another part of routine maintenance.

How can I tell if my car battery is bad? ›

Watch for these five telltale signs of a bad battery so you aren't caught out in the cold!
  1. Dim headlights. ...
  2. Clicking sound when you turn the key. ...
  3. Slow crank. ...
  4. Needing to press on the gas pedal to start. ...
  5. Backfiring.
7 Jan 2018

How can I test a battery without a tester? ›

How To Test Batteries Without A Battery Tester - YouTube

How do I know if my battery is maintenance free? ›

Maintenance-free batteries are also easily identifiable because they do not have filler caps. A large, plain unremovable flat cover encases the battery housing and may be labeled with the words “Maintenance Free.” Today, virtually all new cars come standard with maintenance-free batteries.

Do they check your battery when you get an oil change? ›

The Car Battery

Every time you take your car in for an oil change, the battery is checked to make sure there are no signs of leaking or erosion and that it holds a charge.

Is 11.6 volts enough to start a car? ›

When the voltage of the starting power supply is lower than 11.8V, it will be difficult to start the car. You can choose to turn off all other electrical appliances and try several times. When the battery voltage is lower than 10.8V, it is generally impossible to start the car.

Is 12.4 volts enough to start a car? ›

Without the engine running, a fully-charged battery registers 12.6 volts. At 12.4 volts the battery is considered 75% charged and can still ignite your engine.

Is 12.3 volts OK car battery? ›

12.6V volts or above - Your battery is healthy and fully charged. No further action is required. 12.5 volts - Your battery is at a healthy state of charge, but we'd recommend re-checking it within a few days to ensure the voltage hasn't dropped any further.

How accurate are car battery testers? ›

A dead battery is easy to check and most testers are 100 percent accurate.

What voltage is too low for a 12-volt battery? ›

Generally, your car battery voltage is too low if it is reading at 12.4 volts or under. Your 12-volt battery should read at around 12.65 or higher on your voltmeter if it's healthy and fully charged. If your battery drops to 12.5 volts, consider recharging it back to a full charge.

Is 13.5 volts good for car battery? ›

With the engine running, your battery's voltage should be somewhere between 13.5 and 14.7 volts.

What shortens the life of a car battery? ›

Factors that can shorten its life include an extended period of partial or full discharge, vibration from not being properly secured, under- or overcharging, extreme temperatures, water loss, electrolyte contamination and corrosion on terminals.

Can a car battery last 10 years? ›

Car batteries have a finite lifespan

Batteries gradually deteriorate until they can no longer provide enough power to start an engine. This wear time could take three to five years and a vehicle's usage pattern is one factor contributing to the rate at which a battery will age.

How much should a car battery cost? ›

Car batteries typically last anywhere from two to five years, depending on the battery type, climate and vehicle. Based on the make and model of your vehicle, you can expect to pay around $50 to $120 for a standard car battery and around $90 to $200 for a premium type.

Can a car battery test good and still be bad? ›

If a vehicle has a battery that keeps running down, but the battery and charging system both test OK, the problem may be a key-off current drain that's sapping the battery of its reserve power.

How can I test my car battery at home? ›

Connect the multimeter to the positive and negative battery terminals. If you don't have a voltage of around 12.6 volts, you may have a bad battery. Now start the car, and look for a revised voltage over 10. If your voltage drops below 5 when the car is running, it is bad and should be replaced right away.

What can drain a car battery when the car is off? ›

What may drain a car battery when it's off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery — which is why you typically don't have to worry about the battery dying while you're blasting the radio on your drive to work!

How can you tell if a 12v battery is good? ›

How to Test a Car Battery with a Multimeter - YouTube

How can I check my car battery without tools? ›

How to Check Your Car Battery - Without Tools - YouTube

How can I check battery health? ›

Go to settings > Battery and device care > Diagnostics. You can now tap on battery status to check its health status. There are other features as well (Camera, speaker and more) of the phone that you can test to see if they are working fine or you should get them fixed.

How long does a maintenance free car battery last? ›

As for the service life, the replacement cycle of a maintenance-free battery under normal conditions is about 3 years, which is equivalent to that of a lead-acid battery.

What does the green dot mean on a car battery? ›

Check your battery's state of charge using the 'Eye' or 'State of Charge' indicator on the top of the battery. “Green” indicates a healthy battery, “Black” or “Clear” indicates your battery may need charging or servicing.

Can you put tap water in a battery? ›

The most common type of water used in batteries is distilled water. Other types are deionized water and water from reverse osmosis. Ordinary tap water should not be used because it may contain an excessive amount of impurities that will degrade battery performance.

What do mechanics check during an oil change? ›

First, the mechanic or technician will check the oil level. Then, he or she will drain the car's oil. Next, the technician will take out the oil filter and examine it. If the filter is coated in oil, it will need to be replaced.

Can AutoZone change my battery? ›

Yes, AutoZone installs batteries. Not only does AutoZone sell batteries, but they can install them, too, in most cases. If your car's battery is dead, won't hold a charge, or if your car won't start, it may be time for a new battery. AutoZone carries a large selection of batteries and installs them.

How can I test my car battery? ›

How to test a car battery - YouTube

How does a weak battery affect a car? ›

A bad car battery often leads to rise of temperatures along with high voltage. High amperage leads to heavy-duty push to a car's engine, leading it to heat excessively. Possible effects of overheating include a damaged or a blown engine.

Can a car battery last 10 years? ›

Car batteries have a finite lifespan

Batteries gradually deteriorate until they can no longer provide enough power to start an engine. This wear time could take three to five years and a vehicle's usage pattern is one factor contributing to the rate at which a battery will age.

Is it a battery or alternator? ›

If your engine won't turn over or takes far longer than usual, it's time to grab the jumper cables and attempt a jump-start. If your engine starts and stays running but won't start again later, it's likely a battery problem. If your vehicle immediately stalls, it's probably a bad alternator.

How much is a new car battery? ›

Car batteries typically last anywhere from two to five years, depending on the battery type, climate and vehicle. Based on the make and model of your vehicle, you can expect to pay around $50 to $120 for a standard car battery and around $90 to $200 for a premium type.

Does an old battery affect car performance? ›

Internal components: A weak battery affects performance by causing damage to the engine's internal parts. The low voltage causes the temperature to go up, and overheating can result, which causes damage to the engine parts.

Should I replace my 7 year old car battery? ›

General wisdom says you should replace your car battery about every three years, but you could end up needing a replacement sooner. Factors like your climate and driving habits can affect your battery's lifespan and leave you needing a new one before the three-year mark.

What type of car battery lasts the longest? ›

Lithium-Based Long Lasting Car Batteries

Newer types of lithium metal and lithium ion batteries are known to last more than 5-6 years depending on the design and the type of car you're using it for.

Should I replace a 4 year old car battery? ›

So the rule of thumb is simple for battery replacement: You have approximately four years before the battery will theoretically begin its slide from chemical powerhouse to chemical paperweight. At the four-year mark, start watching for symptoms (which we'll discuss in a bit) and be prepared to take action.

What does a clicking sound mean when your car won't start? ›

Car Makes a Series Of Rapid Clicks

This lack of electrical current could be because of a failing battery, a bad connection at the battery or even a bad alternator that isn't properly recharging your battery. Best case scenario, your battery or posts need cleaning.

What happens when your car clicks but wont start? ›

It might be a faulty starter.

One of the symptoms of a bad starter is a single clicking noise when you turn the key or push the start button. Tapping the starter can sometimes get it going again, but no guarantees. Most likely, you'll need to get your starter repaired or replaced.

Why does my car struggle to start but runs fine? ›

Why your car struggles to start but runs fine. There are a number of reasons why your car might be slow to start but runs as-normal once it gets going. Causes can vary from weather conditions to battery health, wiring issues, starter motor concerns and fuel-pump health.

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