Car Battery Types & Group Sizes

Wondering about car battery types and which is right for your vehicle? You've come to the right place. It pays to know the basics of batteries so you can ensure the expert care of your car.

When you need a new car battery, come into a Firestone Complete Auto Care in your neighborhood. We'll install the best battery choice from our selection of car battery types made by the industry's top car battery manufacturer. We'll size up your vehicle's OEM battery and electrical system, and then set up the proper car battery group size to power your ride. Learn more about car battery types, group sizes and other specifications that matter when selecting a car battery.

Car Battery Types

Wet Cell (flooded battery): Wet cell batteries are lead acid batteries designed for automotive use. There are two popular versions of wet cell batteries available as a SLI (starting lights ignition) starting battery and a deep cycle (marine) battery. Wet cell car batteries are serviceable and should be checked routinely, but in some cases there are maintenance free wet cell batteries as well.

  • SLI Battery: SLI batteries are designed to start your car with fast short bursts of energy to start your engine. There is a greater lead plate count, but thinner to cover more surface area and have a custom material. Most automobiles come with a generic SLI battery from the factory.
  • Deep Cycle Battery: Marine deep cycle batteries will last longer and are designed for long-term energy delivery. The bursts of energy are not as strong as a SLI battery due to the fact that the lead plates are thicker and can endure many deep cycle charge and discharges.

VRLA Batteries (valve-regulated lead-acid battery): A sealed battery with no venting of gases. These batteries are great for use in small spaces with no ventilation and are great when in storage because they are sealed. VRLA batteries don't leak or release hydrogen gas and are considered the safest Wet cell lead acid battery. The only downside is the VRLA batteries are sealed, leaving them unserviceable. There are two types of VRLA batteries, the gel cell battery and the AGM battery.

  • Gel Cell: A gel cell is considered a VRLA battery and is designed with a gelified electrolyte. Gel batteries are extremely resistant to hot temperatures, spillage, physical shock, and electrolyte evaporation. Gel batteries function just like a wet cell battery, except they are sealed and dry.
  • Absorbed Glass Mat (AGM): An AGM battery is also considered a VRLA battery and is designed with the electrolyte held in glass mats. These glass mats are very thin fibers in the battery and are meshed together to form the electrolyte absorbed glass mat. AGM batteries also work just like a wet battery, without the spilling of battery acid and are sealed.

Car Battery Group Sizes

Batteries do have specific BCI (Battery Council International) group numbers that are specific to the size of the battery case. The BCI battery group numbers do not account for the AH / CCA / RC / CA ratings, dimensions, weight and options (such as handle, flat top and type). To select an appropriate battery for a vehicle, the car battery group size needs to be matched first, then the Amp Hours (AH), cranking amps (CA), cold cranking amps (CCA) and reserve capacity (RC) ratings need to be considered and reference the original manufacturer's specification.

Battery Service at Firestone Complete Auto Care

If you need a new battery, a Firestone Complete Auto Care specialist will do a free battery test and inspection to match your vehicle's car battery group size and type. Just find the knowledgeable auto care expert near you with the Firestone Complete Auto Care store locator and visit us today.

  • What is a Battery Group Size?

    A battery group size is an industry-standard for car batteries that indicates the actual, physical size for a car battery (Height x width x length), as well as the polarity (where the positive and negative battery posts are located on the battery), allowing the vehicle manufacturers to take the battery size into consideration when designing a car, truck, SUV or other vehicles. Battery group sizes also provide a simplified, industry standard in automotive batteries, helping manufacturers of batteries and vehicles alike to reduce costs. Having standard battery group sizes makes replacing your battery at your local Firestone Complete Auto Care store simple, and our technicians and automotive advisors can ensure the proper battery fitment for just about any vehicle on the road.

    Helpful hint: instead of trying to measure the exact size of your car battery with a tape measure, look for the "Group Size" to be printed on the label of the battery. You can also call or visit any local Firestone Complete Auto Care Store to verify your vehicle's correct battery replacement with the vehicle year, make, and model.

  • Different Battery Group Sizes

    Certain vehicle manufacturers tend to use specific group sizes more than others. For example, many General Motors vehicles use (and/or used) a side-post battery. Side post batteries have cable ends that screw into the side of the battery, as opposed to having battery posts on the top of the battery. These group sizes are typically 70, 74, 75 and 78.

    European vehicle manufacturers (Volkswagen, Audi, Mercedes Benz, BMW, etc.) typically use an "International" style of battery where the top posts are recessed in the corners so that the top of the battery posts are about equivalent to the main height of the battery. Many of these international (European) battery group size fitments have a specialized ventilation system as part of the battery, and some are also installed in the trunk or even under the back seat (as opposed to the typical placement under the hood). These group sizes are typically 41, 42, 47, 48 and 49.

    Helpful Hint: the installation process of these batteries is often more difficult than other batteries. While the installation rates may be a little more for these battery group sizes, it may very well be worth it to trust it to the expertise of Firestone's certified technicians. Call or drop by your local Firestone Complete Auto Care store for more details.

    Japanese vehicles, many other imports and most American-made vehicles typically use a group size with a standard, top-post battery fitments. These are the most-common battery group sizes that most people are used to seeing. While these are more common and seem easier to replace, it is still important to use the proper group size so that your car battery stays secure in your vehicle's battery tray. For example, some group sizes are the same width and length, but have a lower height. If a taller battery is mistaken for a shorter group size, it may not fit properly in the battery tray and/or battery hold-down, or the battery post could even make contact with the metal hood of the vehicle, causing a spark, a short or a vehicle fire. Again, as a precaution, please consult with your Firestone technicians for the proper battery fitment for your specific vehicle year, make and model. In general, these more-common battery group sizes are 24, 24F, 25, 34, 35, 51, 51R, 52, 58, 58R, 59, and 65.

    Helpful Hint: Some vehicles have other larger batteries available as an option. A physically larger battery usually has more power and reserve time than a smaller battery.

    See if a larger battery is available for your vehicle.

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