Without a strong, reliable car battery, drivers could get stranded at home or on the road. But buying a good replacement isn’t as easy as simply finding one that fits.

Consumer Reports testers found that car batteries vary greatly in how they perform—even within individual brands.

CR just posted our latest car battery test results featuring lead-acid and absorbent glass mat (AGM) batteries. Each year, we test two batches of 15 models over six months. For each model, we anonymously buy five examples through a variety of retailers, meaning we test 150 batteries annually.

CR now has 69 car battery models in our ratings, including some brand-new models joining the ranks and some we retested. We retest models because we've found that performance can vary over time as construction and formulations are tweaked, even when the model name remains the same. 

The well-recognized DieHard brand sold by Sears is a classic example of why you should buy based on data rather than brand perceptions. There are certain DieHard models at the top of a category and some DieHard models at the bottom.  

How We Test

We evaluate batteries three ways:

Cold-cranking amps (CCA) is a measure of how well the battery starts an engine during extreme cold weather. We use a freezer to simulate winter conditions, cooling batteries to 0° F, and rate batteries based on their performance. 

Reserve capacity indicates how long a battery can run your vehicle if the charging system—the alternator, stator, and rotor—fails. It’s also a measure of how long you can accidentally leave the headlights on in the mall parking lot and still get the car started without needing a jump start. To test reserve capacity, our engineers measure how long it takes a fully charged battery to be discharged down to 10.5 volts, which is considered to be fully discharged.

Battery life is measured by repeatedly discharging and recharging at a test temperature of about 167° F for 15 weeks, or until performance drops to unacceptable levels. This simulates the hot under-hood conditions a battery can face during the summer, the hardest time of year for batteries because of the heat. The higher the score, the longer the battery will be reliable.

More on Car Batteries

“By focusing on the attributes that matter most to consumers, the results from our exhaustive testing empowers shoppers to choose the best car battery for their needs,” says CR senior project leader John Banta. “We just hope that consumers are proactive in buying batteries before they are left stranded.”

Most batteries last two to four years in hot climates and four to six years in cooler climates.

With these latest test results, we are shifting our focus slightly to emphasize battery groups that are most popular with our subscribers, rather than with the population at large. To that end, we are phasing out size 75, and we are adding 51R, Group 47 (H5), and Group 49 (H8). The 51R is popular among Honda models, and the others are common among European car brands. We are looking to add more brands to the ratings this year.

Below, we highlight the best car batteries in each category. Click through the model name for detailed test results or go direct to the car battery ratings

Check the owner’s manual to see which is the right size battery for your car.

Best Car Batteries

Here you'll find the top-performing battery in each category we test: Group 65; Group 34, 78 & 34/78; Group 24 & 24F; Group 35; Group 75; Group 48; Group 51R; Group 49 (H8); and Group 47 (H5) car batteries.

Top Picks


Reserve capacity


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