To help our members make a smart decision about replacing their car battery, Consumer Reports tests more than 100 individual car batteries in our lab every year. And not just once—in fact, we test five units of each rated model to ensure that your experience matches our results. 

After all, car batteries are essential to every commute, errand, and road trip. It can be easy to take it for granted that your car will start each and every time, but batteries do wear out—sometimes when you least expect it.

In this article

Our tests are tough by design. We charge and discharge the batteries 180 times while in a 167º F water bath to simulate temperatures under a car’s hood and find out how long they’ll last. Then we 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.

Many factors impact battery life, with weather being one of the most significant. (While batteries typically fail in cold temperatures, hot temperatures cause degradation.) That’s where our extreme testing can separate the promising batteries from those that come up short.

Many of the highest-scoring batteries use pricey absorbed glass mat (AGM) technology to create their power. 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 Paolo Fu, who oversees testing of car batteries at Consumer Reports.

“Price doesn’t necessarily mean better performance,” Fu says. “We’ve got some less expensive batteries in our ratings that score very well.”

Below you’ll find the top-performing battery in each category we test. You’ll also find information on how to know which type of battery your car needs and tips for buying a replacement battery.

We present the best car batteries for the money in seven different sizes: Group 24/24F, Group 35, Group 47 (H5), Group 48 (H6), Group 49 (H8), Group 51R, and Group 65. These numbers indicate size in the same way AA, AAA, C, and D indicate the size of batteries you’d use to power home electronics. 

There are other sources to help you select the proper battery, including your owner’s manual, battery company websites, in-store guides, 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. 

In our list of select car batteries, we show ratings for:

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. The basic specs for a replacement battery can be read from the battery currently in your car, but if you bought the car used, it is wise to consult the owner’s manual to ensure the correct battery size and type is used. 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.

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We investigate, research, and test so you can choose with confidence.