Like virtually all other car parts, a dying battery and ensuing battery replacement are common (and often annoying) occurrences.
As luck would have it, a faulty car battery doesn't often happen suddenly.
Usually, there are signs the battery is beginning to fail, which include slow engine cranking, a clicking sound when you try to start the engine, dim headlights or cabin lights, or other electrical issues.
The bad news is that if you're experiencing any of these symptoms, it's likely time to replace your car battery.
The good news, though, is that changing a car battery is a relatively simple job that shouldn't take more than 15–30 minutes and requires only basic tools.
In the following guide, we'll walk you through the step-by-step process of replacing a faulty car battery.
We'll also cover a few other important topics like how to test a car battery, which battery terminal to disconnect first, how long car batteries last and car battery costs and warranties.
Quick Battery Health Checklist
Your battery may need replacement if:
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The car cranks slowly
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Voltage reads below 12V when checking with a multimeter
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Voltage drops below 10V when starting and checking with a load test
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You’ve needed multiple jump starts
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The battery is older than 3–5 years.
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Your battery is heavily corroded, rusty, or visibly damaged
Tools and Supplies Needed to Change a Car Battery
Although it's often easier to pay somebody else to change your car battery for you, here at Tool Troopers, we're all about teaching people how to do it themselves. And lucky for you, changing a car battery is one of the easiest DIY vehicle maintenance tasks.
Here's what you'll need to get the job done right!
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Socket wrench
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Adjustable wrench
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Battery terminal cleaner
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Gloves
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Safety glasses
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Replacement battery
How to Change a Car Battery (Step-by-Step)
Below is our step-by-step walkthrough for changing your car battery. As mentioned, this is a relatively easy maintenance task, even for beginners and non-mechanically inclined individuals.
Step 1 – Turn off the vehicle and open the hood
Whenever working under the hood, it's important to shut the engine off to ensure there are no moving belts or fan blades that could cause serious injury.
Step 2 – Locate and inspect the battery
On most older vehicles, the battery is easy to spot. It's usually located toward the front of the engine bay, on either the left or right-hand side of the vehicle.
However, on newer vehicles, batteries are often protected under a plastic cover that helps keep water, dust, and dirt out. It should still be easy enough to spot. But you may need to remove a plastic cover to access the battery and its terminal.
If all else fails, you can always refer to your vehicle's owner's manual to help you locate the battery.
Step 3 – Disconnect the battery cables
The next step will be to use a socket or an adjustable wrench to loosen the connectors and disconnect the cables from the battery posts.
Note that it's safe to touch the battery terminals individually with your tools. But you never want to make contact with both the positive and negative terminals, which can cause sparks and electric shock.
Start by removing the negative terminal first, then the positive terminal second. Then, pull the cables aside to avoid any accidental contact.
Step 4 – Remove battery hold-down bracket
Most car batteries have a clamp or bracket securing them in the battery tray. This is typically held in place by a long bolt that can also be removed with a socket or adjustable wrench.
Once the hold-down bracket has been loosened or removed, you should now be able to lift the battery out of its tray.
Step 5 – Carefully lift out the old battery
One important thing to remember is that car batteries often weigh between 30 and 50 lbs.
So it's important to lift carefully, avoid straining your back (especially for the older gentlemen and ladies reading this), and to be careful when setting the battery down so as not to crush any toes, fingers, or anything else you might have lying around.Step 6 – Clean battery terminals
Next up, you'll want to clean your battery cables and connectors with a battery cleaner and a wire brush.
Even if your connections aren't severely corroded, it still helps to give them a quick cleaning. This removes any small bits of rust or dust that may be present and ensures a good, strong connection once you install your new battery.
Step 7 – Install the new battery
Now, it's time to gently lift the new car battery onto the tray. Before placing the new battery, it's a good idea to ensure the correct orientation and positioning.
Remember, these batteries are heavy. So it's better to place it properly the first time, rather than needing to reposition the battery once it's been placed.
Step 8 – Reconnect terminals
When reconnecting, first the positive cable, then the negative cable. This is the exact opposite of when disconnecting the cables and removing the battery.
Use a socket or adjustable wrench to firmly tighten the nuts to form a solid connection and keep the cables secure while driving.
Step 9 – Secure the battery bracket
Finally, you can secure the hold-down bracket and tighten it firmly into place. Replace the cover, if applicable, and you're done!
Step 10 – Start the vehicle and test
Now, it's time to start the vehicle. If the vehicle starts easily, you're now the proud owner of a brand-new car battery you replaced yourself!
If the vehicle doesn't start or if it starts and then dies, check your connections and try again. If you haven't cleaned your terminals and connectors properly, there may be corrosion or dirt preventing a good connection.
However, you may also have an issue with the vehicle's starter, the alternator, or other parts that are preventing the engine from running properly.
What a Car Battery Actually Does
Most people know that cars, trucks, SUVs, and even RVs have batteries. But many don't fully understand what those batteries do other than powering their headlights.
A car battery also provides electrical current for the engine's starter motor, modern push-start ignition systems, and other onboard electronics and computers.
Now, because modern vehicles typically have more electronics on board, they generally rely more heavily on batteries compared to older vehicles.
How Long Does a Car Battery Last?
The average lifespan of a car battery is typically between three to five years. However, many factors influence how long your battery will last. So, while some batteries may fail after just a few years, others may last longer than 5 years, depending on conditions.
A few factors that shorten battery life include:
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Exposure to extreme cold or heat
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Frequently driving only short distances
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Leaving lights or electronics on often
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Corrosion, rust, and poor connections
Pro Tip - Sometimes car batteries die just because you left your lights on or when the temperature gets too cold. In these cases, you may be able to get your car started against by using a jump starter. Using a jump starter is quick, easy, and often safer than using a set of jumper cables to perform the same action.
How Often Should You Replace a Car Battery?
As a general rule, most car batteries should be replaced between 3 and 5 years, but it really depends on the vehicle and the battery's mileage rather than age.
That said, it's often better to be proactive about battery replacement than to find yourself stranded with a car or truck that won't start.
Even if your battery still looks new and seems to be working fine, you could be just a short drive away from needing to call for roadside assistance.
At the very least, we strongly recommend checking and servicing your car battery every 3 years or so to ensure it's properly connected and still in good working order.
How to Test a Car Battery
Even if you're not the most mechanically-inclined individual, you'll be glad to know that testing a car battery is relatively straightforward and can be done in just a few minutes when you've got the right tools on hand.
The two most common methods are using a digital multimeter or using a battery load tester. Below, we walk you through each process.
Method 1: Testing A Car Battery With A Multimeter
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Start by making sure the car's engine is turned off and has been off for at least 30 minutes, which allows the battery voltage to stabilize.
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Make sure your multimeter is set to the DC Voltage (V) setting. If the device is not automatic, you'll also need to set it to the 20V range.
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Connect the multimeter's red probe/clamp to the battery's positive terminal and the black probe/clamp to the battery's negative terminal.
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Allow the device to read the battery's voltage. A healthy battery should show a voltage reading of 12.6 volts or higher.
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If the reading is below 12 volts, it may need to be replaced.
Method 2: Load test
The next method is how mechanics test battery strength by simulating the demand of starting a vehicle's engine. Essentially, they use a load tester, a device that takes a voltage reading when the vehicle is started and the engine is running, rather than when it's turned off.
To test your car battery with a load tester:
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Connect the tester clamps to the battery terminals.
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Apply the load for about 10 seconds.
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Check the reading.
If the voltage falls below about 9.6V during the load test, your battery is weak and should likely be replaced.
Bonus Method: Auto parts store testing
Some auto parts stores, like AutoZone or Advanced Auto Parts, may even offer free battery testing. This may or may not be available, depending on your specific location.
However, even if a shop charges for this service, it can be well worth having your battery checked every 3 to 5 years to make sure it's still in good working order.
How Much Is a Car Battery?
Like all car parts, batteries vary in price from budget-friendly models that will likely only last 3 years at most to premium AGM batteries that are meant to be more durable, maintenance-free, and to deliver high performance for longer periods of time.
Typical price ranges
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Budget batteries: $80–$120
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Mid-range batteries: $120–$200
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Premium or AGM batteries: $200–$350+
The type of battery you're looking at is just one factor that can influence cost. But vehicle size, voltage, and cold cranking amps (CCA), as well as brand and warranty, all have an impact on how much a car battery will cost.
That said, we typically recommend mid- to high-end batteries. Yes, they cost more. But they're less likely to fail prematurely.
On top of the battery cost, it's also good to include installation costs in the equations. At most shops, they'll sell you a battery and install it for somewhere between $20–$75.
However, you can easily cut this cost out by learning to change your battery yourself, which is exactly what we explain below!
Pro Tip - We also have a dedicated guide on how to tell if your issue is caused by your battery or the starter. Most of the time, replacing your battery will get you back on the road. But here's a good read if you're still having car troubles: Car Won't Start? How to tell if it's the battery or starter?
Important Safety Tips When Replacing a Car Battery
Inspecting, testing, or replacing a car battery is a relatively safe process.
However, there are some important safety tips to keep in mind, such as:
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Always make sure the engine is turned off before opening the hood
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Wear gloves and eye protection
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Avoid sparks and open flames
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Do not tilt the battery
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Always lift heavy batteries with your legs, and not by straining your back
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Dispose of the old battery properly
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Batteries contain sulfuric battery acid
Which Battery Terminal to Disconnect First
Although it may seem trivial, it's important to always disconnect the negative terminal first. Following the proper disconnection order prevents electrical short circuits, protects your vehicle's electronics, and reduces the risk of sparks.
The safest order of operation is always to disconnect the black/negative terminal first, then the red/positive terminal.
Then, when reinstalling your cables, follow the reverse order: connect the red/positive terminal first, then the black/negative terminal last, which prevents accidental grounding.
How to Disconnect a Dead Battery
We already covered this in the section above on changing a car battery. But here's a quick rundown on how to disconnect a dead battery.
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Turn the vehicle off completely.
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Open the hood and locate the battery.
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Identify positive (+) and negative (-) terminals.
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Loosen the negative terminal clamp.
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Remove the negative cable and move it aside.
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Loosen the positive terminal clamp.
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Remove the positive cable.
Pro Tip - Always keep your tools and fingers away from battery terminals. Accidentally touching the positive and negative terminals at the same time can cause sparks and electrocution.
Car Battery Warranty Explained
Many car batteries are backed with a straightforward warranty that covers manufacturing defects and premature failure.
Battery warranties vary based on brand and model. Most lower-priced batteries are covered for 2-3 years, whereas premium batteries and AGM types are often warrantied for 4-5 years with prorated warranties.
If your battery fails within these time periods, the manufacturer may offer you a free replacement.
However, it's also important to understand that not all car batteries are covered by warranty, and that improper installation, physical damage, and corrosion can void your warranty.
Either way, it's important to ask about warranty coverage when purchasing your battery, keep your receipt, and register for coverage if needed.
Where to Recycle or Dispose of Your Old Car Battery
Another important consideration is that you can toss your old car battery in the trash. Not only are car batteries not biodegradable or recyclable, but they also contain toxic battery acid that can be harmful to the environment.
Luckily, most stores that sell car batteries will recycle or dispose of your old batteries.
You may also be able to dispose of your old batteries at a repair shop or mechanic, local recycling centers, or through local core return programs.
Final Thoughts: Replacing a Car Battery Is One of the Easiest DIY Repairs
If you're worried about the cost of buying a new battery and paying a mechanic to install it, you'll be glad to know that replacing a faulty car battery is simple and takes only 15 to 30 minutes.
Not only is DIY battery replacement cheaper, but knowing how to test your battery and replace it before it fails prevents you from being stranded.
Then, once you’ve done it once, changing a car battery becomes a quick, five-minute job you’ll never need to pay a mechanic for again.
Pro Tip - Looking for essential car accessories? TOOL TROOPERS is proud to have an array of high-quality car, truck, boat, and RV accessories that we're sure you'll love. Browse our shop to learn about JUMPFORCE PRO, TIRESHIELD PRO, FIRESHIELD PRO, and TITANPATCH PRO.
FAQ Section
How long does a car battery last on average?
Most car batteries last 3–5 years, depending on climate, driving habits, and vehicle electronics. Extremely hot or cold weather, frequent short trips, or deep discharges can also shorten a car battery's lifespan.
How much is a car battery?
Most car batteries cost somewhere between $120 and $250, though premium AGM batteries can cost $300 or more. Store, battery type, output, vehicle size, brand name, and installation costs are all factors that can influence the price of a new car battery.
Which battery terminal do you disconnect first?
Always disconnect the negative terminal first, then the positive terminal second, to prevent electrical shorts. This also helps prevent sparks and lowers the risk of injury while swapping out a car battery.
Can you change a car battery yourself?
Yes. Most drivers can replace a battery in 15–30 minutes with basic tools. Even if you're not the most mechanically inclined person, it's relatively easy to swap out an old car battery with a new one.
How often should you replace a car battery?
A good rule is to test it after 3 years and replace it between 3 and 5 years. At the very least, we recommend testing your car battery every 3 years with a multimeter or load tester to ensure it's still in good working order.
What happens if you disconnect the positive terminal first?
Disconnecting the positive terminal first increases the risk of short circuits or sparks if the tool comes into contact with metal. Most of the time, this is harmless, but short circuits can damage your vehicle's electronics, and sparks can ignite nearby fumes or materials if present.
Do you need to reset anything after replacing a car battery?
Some vehicles may require resetting. You'll likely need to reset your radio presets, clock, and window auto functions. But many modern vehicles have onboard computers that keep these settings saved, even when the battery is disconnected or replaced.
Can a car battery suddenly die without warning?
Yes, especially in extreme weather or if the battery has internal damage. Sometimes, you may be lucky enough to get a warning that your battery is about to give out. But car batteries can work fine one day and fail completely the next. That's why proactively testing and/or replacing your car battery is important.