Like shoes, car batteries come in a range of sizes, styles, and fits.
Sep 5, 2023|3 min read
Austin Lott | Capital One
Updated on 9/19/2023
QuickTakes:
- What battery group size means
- Where to find car battery information
- What matters in addition to size
When you're looking to replace your battery, you should take into account specifics such as the battery's shape, how it fits into your vehicle, and how powerful it needs to be.
Size is just one of the factors to keep in mind when shopping for a new car battery. You can use a battery group size chart to figure out which sizes are standard, but the physical dimensions of a battery are just one of a few factors that are important.
What Is a Battery Group Size?
Although car batteries all perform the same functions, they come in several shapes and sizes. Battery Council International created a group size chart to take some of the guesswork out of shopping for a new battery by assigning a specific set of dimensions and a size number. The resource is a bit like a shoe-size chart for car batteries. For example, a size 34 battery is 10 1/4 inches long, 6 13/16 inches wide, and 7 7/8 inches high, regardless of brand or cost.
Just as you'd try on a pair of shoes to ensure a proper fit, you should find the correct battery group size for your car, because a battery that's too big might not physically fit in your vehicle. Even if you could shoehorn a bigger battery into your car or truck,you might not be able to properly secure it using the , meaning the battery could move around on a bumpy or twisty road or in an accident.
Where to Find Your Car's Battery Group Size
Your vehicle's owner's manual typically provides the battery group size. If that information isn't listed there, ask your local dealership's service department or a parts store. The battery size should also appear on the battery in your car, but double-check that the battery in your vehicle is the correct size before buying the same thing. Many battery manufacturers make this information accessible online as well.
What Else to Consider When Buying a Battery
Most of the batteries installed in new and late-model cars feature a pair of labeled positive and negative. Still, some vehicles require a battery with side-mounted terminals.
These battery types aren't interchangeable. Top-mounted terminals might not clear the hood in a car designed to take a battery with side-mounted terminals, and it could be impossible to secure the battery cables if you order the wrong type. You can generally find this information by looking at the battery in the owner's manual or online or by examining the way your current battery is hooked up.
What's inside the battery is also important. There are several battery types available, including lead-acid and absorbed glass mat. It's important to determine which kind your vehicle needs. Another key part of the battery is its cold-cranking amp rating, which concerns how many amps a battery can deliver to help start a car engine in cold weather.
Even if a battery fits into your car, it might not be powerful enough to start the engine on a cold day. Remember that a battery's physical size isn't always proportional to its cold-cranking amps or starting power.
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FAQs
Interpreting BCI Group Sizes
Deciphering BCI group sizes is pivotal to selecting the appropriate battery for your needs. The group sizes encompass not only the physical dimensions of the battery but also the terminal orientation and hold-down type, which are crucial for proper fit and function.
Does battery group size really matter? ›
Interpreting BCI Group Sizes
Deciphering BCI group sizes is pivotal to selecting the appropriate battery for your needs. The group sizes encompass not only the physical dimensions of the battery but also the terminal orientation and hold-down type, which are crucial for proper fit and function.
What group size battery do I need? ›
You can look in the battery section of the Owner's Manual of the car or truck. If the owner's manual can't be found, look at your existing battery and see what BCI Group Size is already installed. The Group Size is labeled in several places on the battery. Generally on the top and/or on the front of the battery.
What does group size on a battery mean? ›
The Battery Council International (BCI) has created designations known as group sizes that provide a battery's exact physical dimensions. They provide the length, width, and height in both inches and millimeters.
What happens if I use the wrong group size battery? ›
By installing a larger battery, you may inadvertently install a battery of higher voltage than is required. This could cause undercharging and even burning out the electrical system in the car.
Is a group 27 battery better than a group 24? ›
Group 27 battery is a lot bigger than group 24 cells. But it provides more power. If size is not an issue, they can be interchangeable.
Is group size all that matters for battery? ›
Size is just one of the factors to keep in mind when shopping for a new car battery. You can use a battery group size chart to figure out which sizes are standard, but the physical dimensions of a battery are just one of a few factors that are important.
What is the most popular battery size? ›
Also known as “double A”, AA batteries are by far the most popular battery size.
What is the difference between Group 34 and 78 battery? ›
The "34" number refers to a battery of specific dimensions with top terminals, while a "78" number also refers to a battery of specific dimensions with side terminals. The physical dimensions of these two batteries, at least relative to their size without terminals, happens to be identical.
Can a battery be too powerful for a car? ›
Since the fuse panel protects your car's electrical systems from power surges and spikes, using a larger battery can cause current fluctuations. And this can damage the regulator on the alternator which then increases the chances of the stereo system, and other electronics getting damaged.
In general, for both CCA and RC, the higher the number the better. However, if you live in a cold climate, the CCA rating should be an important consideration in choosing a battery. Conversely, if you live in a high heat climate, you don't need as much CCA.
Can you mix battery group sizes? ›
Why Can't You Mix Battery Sizes and Chemistries. Mixing battery sizes and chemistries is generally discouraged because it can lead to various safety and performance issues, such as battery leakage and sub-optimal device performance.
Does battery size affect battery life? ›
In addition, a larger battery may also have a longer life and a longer charge-discharge cycle before its performance starts to degrade. It is important to note that the size of a battery is not directly related to its energy density, which is the amount of energy stored in relation to the weight or volume of energy.
Will a higher CCA battery last longer? ›
It may crank harder, but it generally won't last as long.
Will a bigger battery hurt my alternator? ›
No, you cannot damage the alternator if you connect a battery of a different capacity (Amps hour), if the battery has the same nominal voltage (typically 12V). A larger capacity battery will start the car as easy or easier than a lower capacity battery. A smaller capacity may struggle to start the car.
Can you put a 6 cylinder battery in a 4 cylinder car? ›
A mismatched battery/alternator combo could cause your alternator to overheat and shorten its life. Picture putting a battery designed for a large luxury six-cylinder SUV with lots of accessories into a small, base model four-cylinder sedan.
Can I use a 24F battery instead of 35? ›
They are basically the same size except for length. Our Group-35 can be used in place of a Group-24; it is only 1-inch shorter left to right dimensions.
Austin Lott | Capital One