When selecting a new battery for your car, you can usually take the approach that bigger numbers are generally better. Your manufacturer will recommend a minimum cold cranking amps (CCA) rating for your battery, but choosing a battery with a higher CCA output is fine. A higher rating will help guarantee that your car can start, even on cold days.

Likewise, choosing a battery with more reserve capacity (RC) can be useful if you run many accessories. Your battery's reserve capacity is the energy you can drain with your car off, so more is always helpful. On the other hand, group size is a somewhat more confusing topic, and this article will help you understand why choosing the correct group size for your car is essential.

Group Size: More Than Just Alphabet Soup

Your battery's group size is the (typically two- or three-character) alphanumeric code that designates the physical dimensions of your battery. While group sizes use standardized codes in the sense that two batteries of the same group size will have the same dimensions, the codes don't have any specific meanings. Instead, you'll need to consult a chart to determine the dimensions of each group size.

The good news is that you don't need to worry about wading through a huge table to find the right battery for your car. Your owner's manual should list a group size rather than a set of dimensions, allowing you to walk into any auto parts store and select the appropriate size. Some cars may support more than one battery size, so your manual might list multiple group size codes.

How Group Size Affects Your Battery

The difference between one group size and another can sometimes be surprisingly small. For example, Group 24 and Group 34 batteries are identical in size, aside from a 1-inch height difference. As a result, you shouldn't necessarily expect that a higher numerical group size or larger physical dimensions will translate into more powerful batteries.

While larger batteries typically do offer more capacity, the relatively small difference between group sizes means that manufacturers can't necessarily cram more power into a slightly larger housing. In other words, if your car can support more than one group size, choosing the larger option doesn't necessarily mean a better battery. Always look directly for the CCA and RC ratings.

Why Choosing the Correct Group Size Matters

So, why does using only your manufacturer's recommended group size matter? The simple answer is that larger batteries are unlikely to fit in your car. Even a group size that's only a fraction of an inch larger may not fit properly in the battery tray or be too large to secure correctly. Likewise, too small batteries may not work with your car's mounting hardware.

Although any better with enough CCA will start your car, choosing a battery with the correct group size will ensure a secure fit, guaranteeing that your new battery will be a safe and effective replacement for your old one.

If you're looking for car batteries for sale, visit an auto parts shop in your area.

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