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Does it matter which car battery I use?

The short answer is yes, it does matter which car battery you use. The type of battery you choose can have a significant impact on your vehicle's performance, lifespan, and safety. In this article, we'll explore the key factors to consider when selecting a car battery.

Understanding Car Battery Types

There are several types of car batteries available on the market, each with its own unique characteristics and suitability for different vehicles. The most common types are lead-acid batteries, which can be further divided into wet cell and absorbed glass mat (AGM) batteries.

Lead-Acid Batteries: These are the traditional and most widely used car batteries. They are relatively inexpensive and provide reliable power, but they require more maintenance and have a shorter lifespan compared to AGM batteries.

AGM Batteries: Absorbed Glass Mat (AGM) batteries are a type of lead-acid battery that use a different construction, making them more durable, spill-proof, and maintenance-free. They are generally more expensive but offer longer service life and better performance, especially in vehicles with high-power electrical systems.

When choosing a car battery, it's essential to select one that is compatible with your vehicle's make, model, and year. Using the wrong battery can lead to compatibility issues, reduced performance, and even safety concerns.

Factors to Consider When Choosing a Car Battery

Here are some key factors to consider when selecting a car battery:

Battery Size and Fit: Ensure the battery you choose is the correct size and fits properly in your vehicle's battery tray. Using the wrong size can cause issues with installation and may not provide the necessary power output.

Cold Cranking Amps (CCA): This measure indicates the battery's ability to start the engine in cold weather. Vehicles with larger engines or in colder climates may require a battery with higher CCA ratings.

Reserve Capacity: This refers to the battery's ability to power your vehicle's electrical systems when the engine is not running. Vehicles with more accessories or higher electrical demands may benefit from a battery with a higher reserve capacity.

Warranty and Lifespan: Consider the battery's warranty and expected lifespan, as this can vary significantly between different brands and types. Investing in a high-quality battery with a longer warranty can save you money in the long run.

By taking these factors into account, you can ensure that you select the right car battery for your vehicle, ensuring optimal performance, reliability, and safety.

Can I use a 51 battery instead of 51R?

No, you should not use a 51 battery instead of a 51R. The "R" in 51R stands for "reverse" or "right," meaning the positive terminal is on the right side when viewed from the front, while a standard 51 battery has the positive terminal on the left. A 51 battery will not work because the battery cables are not long enough to reach the terminals in the correct position.
Why a 51 battery won't work

Incorrect terminal position: The 51R battery is specifically designed for vehicles where the positive terminal is on the right side and the negative is on the left. A 51 battery has the terminals reversed.
Cable length: Your car's battery cables are designed to reach the terminals in a specific orientation. Using a 51 battery will put the positive and negative terminals in the wrong positions, making it impossible to connect the cables without forcing them.

What to do instead

Find the correct battery: Purchase a 51R battery to ensure a correct fit.
Check the battery tray: If the 51R battery is a different size than your original battery, you may need to modify or replace the battery tray to ensure it fits securely.

This video explains the difference between 51 and 51R batteries: 15sOPTIMA BatteriesYouTube · Dec 28, 2021
This video shows how to swap a 151R battery with a 51R battery in a Honda Fit: 53sSeb's GarageYouTube · Mar 30, 2025

How do I know which battery will fit my car?

To find the right battery for your car, check your owner's manual for the correct BCI group size, minimum Cold Cranking Amps (CCA), and terminal orientation. Alternatively, you can find the correct battery by looking at the label on your current battery or using an online tool by entering your car's year, make, and model.
Check your owner's manual or existing battery

Owner's Manual: This is the most reliable source, as it will specify the correct BCI group size and minimum CCA needed for your vehicle.
Existing Battery: Look for the "Group Size" (e.g., 24F, 65) and CCA rating printed on the label of your current battery. You can also see the correct terminal layout to ensure the new battery will connect properly.

Use online resources

Most auto parts stores, like AutoZone and Batteries Plus, have online fitment finders.
Simply input your vehicle's year, make, model, and engine size to see a list of compatible batteries.

What the specs mean

Group Size: This number is crucial for ensuring the physical dimensions of the battery (length, width, and height) and the position of the terminals will fit correctly in your car's battery tray and connect securely to the cables.
Cold Cranking Amps (CCA): This is a measure of the battery's power at low temperatures, which is critical for starting your engine in cold weather. Always choose a battery with a CCA rating that meets or exceeds the manufacturer's recommendation.

Other considerations

Battery Type: Modern vehicles may require a specific type, such as an AGM battery, especially those with start-stop technology. If your car came with an AGM battery, replace it with another AGM battery.
Terminal Location: Pay attention to the positive and negative terminal positions to ensure the battery cables will reach without being strained.

What happens if I put a different battery in my car?

Putting the wrong car battery in can lead to a range of issues, from performance problems like slow starts to severe electrical damage that can fry the car's computer, cause short circuits, and even result in a fire. Consequences vary depending on the type of error, such as using a battery with the incorrect voltage (e.g., a 6V6 cap V6𝑉 battery in a modern 12V12 cap V12𝑉 car), insufficient Cold Cranking Amps (CCA), or wrong physical dimensions.

Physical and connection issues

Improper fit: A battery that doesn't fit securely can cause damage or a short circuit.
Poor connections: Mismatched terminal positions can lead to poor electrical connections.
Physical damage: The wrong physical size might prevent the hood from closing or the hold-down bracket from securing the battery properly.

Electrical and performance problems

Slow or no start: A battery with insufficient Cold Cranking Amps (CCA) may struggle to start the engine, especially in cold weather.
Damage to electronics: Using the wrong voltage or a battery that's too powerful can cause current fluctuations that damage the car's computer, alternator, and other electronic components.
Erratic behavior: Electronic accessories may malfunction, and dashboard warning lights may appear.
Shorter battery lifespan: The alternator may not be able to charge the incorrect battery properly, leading to premature failure.
Reduced performance: A low-voltage supply can cause a decrease in performance, and start-stop systems might not function correctly.

Serious safety risks

Electrical fires: Short circuits caused by incorrect connections or a loose battery can lead to sparks and potential fires.
Leaking battery acid: Overload or physical damage can cause the battery case to burst, releasing dangerous acid.

How to avoid problems

Consult your owner's manual: It will tell you the correct specifications, including the BCI Group Size, CCA, and voltage for your vehicle.
Double-check the fit: Ensure the battery's physical dimensions and terminal locations are correct for your car's battery tray and cables.
Ensure sufficient CCA: Choose a battery with enough CCA, especially if you live in a cold climate.
Consider battery type: Modern vehicles with advanced electrical systems may require a specific battery technology, such as an AGM battery.

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Do car batteries have to be an exact fit?

Always refer to your owner's manual or use a car battery size chart to find the correct measurement. A battery that's too big or too small may not fit properly in your car's battery tray or connect correctly to the terminals, leading to potential damage or performance issues.

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.