Best Car Batteries of 2021

CR tests dozens each year to separate the positives from the negatives

Installing one of the best car batteries.

At Consumer Reports, we test 150 individual car batteries every year in our lab to help you make smart decisions when it's time to replace your battery. We test five examples of each rated model.

The tests are tough by design. We charge and discharge the batteries thousands of times to find out how long they’ll last. We also put them in a freezer to see how they’ll perform at 0º F, and we track how long they’ll last if you leave your car's headlights on or the charging system fails.

There are many factors that have an impact on how long a car battery will last, with weather being one of the most significant. (Hot temperatures are harder on batteries than cold.) That's where our extreme testing can separate the ones with promise from those that come up short.

More on Car Batteries

Many of the highest-scoring are pricey absorbed glass mat (AGM) batteries. They're known for having a long service life and being able to tolerate deep discharges—when the battery has been significantly drained to 10.5 volts or below, such as when the lights are left on overnight. But some top-rated lead-acid batteries cost less than many of their competitors, says John Banta, CR's test engineer for batteries.

“Price doesn’t necessarily mean better performance,” Banta says. “We’ve got some batteries that are relatively cheap that score very well.”

Below you'll find the top-performing battery in each category we test: Group 24 and 24F, Group 35, Group 47 (H5), Group 48 (H6), Group 49 (H8), Group 51R, and Group 65.

You'll also find information below on how to know what type of battery your car needs and tips for buying a replacement battery.

Car Battery Groups

Size 24/24F (top terminal): Fits many Acura, Honda, Infiniti, Lexus, Nissan, and Toyota vehicles.

Size 35 (top terminal): Fits most Japanese nameplates, including many recent Honda vehicles, most Subaru vehicles, and most Mazda, Nissan, and Toyota vehicles.

Size 47 (H5) (top terminal)
: Fits many Buick, Chevrolet, Fiat, and Volkswagen models.

Size 48 (H6) (top terminal)
: Fits many vehicles from Audi, BMW, Buick, Cadillac, Chevrolet, GMC, Jeep, Mercedes-Benz, Mini, Volkswagen, and Volvo.


Size 49 (H8) (top terminal): 
Fits many vehicles from Audi, BMW, Hyundai, and Mercedes-Benz.

Size 51R (top terminal): Fits many vehicles from Honda and Nissan.

Size 65 (top terminal): Fits large cars, trucks, and sport utility vehicles from Ford or Mercury.

How to Find the Right Replacement

Before you buy a new car battery, know the correct group number for your vehicle, which varies depending on make, model, year, and engine size.

Batteries are defined by physical size, type, and placement of the terminals, as well as mounting style. Be sure to replace your battery with one that's from the same group so that it will fit its tray and the leads will connect properly.

The basic specs for a replacement battery can be read off the battery that's currently in your car.

There are other sources to help you select the proper battery, including your owner's manual, battery company websites, an in-store guide, or your local mechanic. If you bought a used car, don't assume it has the proper battery installed. Be sure to check with one of those other sources to identify the correct type.

Tips for Buying a Replacement Battery

This year’s results continue to show that buying a battery from a car dealership or mechanic may not be your best bet. For example, three EverStart batteries get a CR's Best Buy designation, and they’re sold only at Walmart. Compared with the batteries sold at dealers or by mechanics, “EverStart's warranties are just as good, and in some cases might be a little better,” says Mark Allwood, a senior market analyst at CR who covers car batteries.

Regardless of where you buy them and what brands they belong to, a majority of batteries are built by a handful of manufacturers, Allwood notes. For example, Duracell car batteries—one of which gets a Best Buy designation—are made by East Penn, a major battery manufacturer.

CR’s experts caution against buying a battery online. There may be shipping restrictions. And although it can save you money over paying a local retailer—as much as $40, Allwood says—it may not be a good idea for those who aren't experienced installing a car battery.

“If you’re not comfortable doing it yourself, you should go to a qualified mechanic,” says John Ibbotson, chief mechanic at CR’s Auto Test Center. “With most cars, it’s a pretty straightforward job, but for some cars, the installation is more involved.” For example, some cars hide the battery under a seat, in the trunk, or behind a wheel well, which may require the removal of parts before installation.

Plus, even older vehicles can require some level of reprogramming by a mechanic when a battery is changed to allow all systems to work.

The good news is that many auto-parts stores—including Advance Auto Parts and O’Reilly—offer free installation of most of the batteries they sell, as does Batteries Plus Bulbs.

Some auto parts chains may allow you to order a battery they don’t stock and install it. Confirm before ordering.

When buying a car battery, it's common to incur a "core" charge. This is essentially a deposit that's refunded when you turn in the battery for recycling. The other piece of advice is to look for a battery with the latest (most recent) date code.  

Group 24/24F