Car Battery Buying Guide
Start Your Engines!

The day your car won't start isn't the best time to shop for a new car battery. But according to our research, that's exactly what most people do.

You will probably have to replace the car battery once or twice during the life of your vehicle because it gets old or worn out from repeated charging and discharging. A dead battery can be a real hassle, especially if you can't find your jumper cables or have to wait for roadside assistance.

Check Under the Hood

Before you go shopping, here are a few tips for getting the best battery for your needs.

Be Proactive
Being attentive to your battery’s maintenance and mindful when the time for replacement is approaching will ensure that you can choose a replacement on your own terms, including properly researching and conveniently scheduling.

Test Batteries Annually
While almost all of today’s car batteries are maintenance-free, we recommend having your battery load-tested by a mechanic annually once it is 2 years old if you live in a warmer climate, or 4 years old if you live in a colder climate.

A Battery Should Fit Your Car and Driving Needs
When it’s time to buy a replacement battery, make sure you get the right size and terminal locations (or type) for your vehicle. Check your owner’s manual or an in-store fit guide before shopping, and see below for the most common sizes.

Choose One That Did Well in Our Battery-Life Test
This is critical if you live in a warmer climate. Frequent high temperatures are very tough on batteries, increasing plate corrosion and more quickly vaporizing the electrolyte needed for current. Long life is especially important if you make many short trips that don’t allow much time for recharging.

Get One That Did Well in Our Cold-Cranking Amps and Reserve-Capacity Tests
These ratings reflect the starting power the battery provides. Most models in our car battery comparison have proved to be at least adequate in both of these tests, but there is performance variation.

Make Sure It’s a Fresh Battery
Batteries lose strength over time, even when in storage. For optimum performance, purchase one no more than 6 months old. Most have a shipping code on the case. Some use a letter for the month (“A” for January) and a number for the year (“8” for 2018); others use a numeric date.

Recycle Your Old Battery
A battery’s toxic lead and acid can easily be recycled, and most retailers will dispose of the old one for you. When buying a new battery, you will probably pay an extra charge that’s refunded if you take the old battery in after installing the new one.

Compare Warranties
It is important to choose a battery with the longest free-replacement period you can get. A battery’s warranty is measured in two figures: the free-replacement period and the prorated period—which allows only partial reimbursement. A code of 24/84, for example, indicates a free-replacement period of 24 months and a prorated warranty of 84 months. But the amount you’ll be reimbursed usually drops off pretty quickly once you’re in the prorated period.

Be aware that signs of neglect—such as low water levels and improper installation—can void a warranty. So can heavy-duty use, such as for high-end car audio and marine applications, if the battery is not recommended for it.

Get to Know the Battery Types

Car batteries come in two basic varieties: the more traditional maintenance-free and the more advanced absorbed glass mat.

Photo of a lead-acid, or "regular" car battery.

Lead-Acid (Regular)

Batteries once required drivers to periodically top off the water in the electrolyte solution, the liquid inside that is the battery’s power source. Modern maintenance-free batteries consume far less water than traditional “flooded cell” ones. Low-maintenance batteries retain their fluid for the life of the battery, and the caps on these models aren’t meant to be removed.

A lead-acid battery will generally cost significantly less than an absorbed glass mat battery. However, it will not hold a charge for as long and is less able to tolerate a deep discharge.



Check Our Car Battery Ratings Here
Photo of an absorbed glass mat (AGM)
 car battery.

Absorbed Glass Mat (AGM)


AGMs are built to better stand up to repeated draining and recharging cycles than standard batteries. They are becoming standard equipment in more cars because modern features such as fuel-saving stop-start systems, electronic safety and convenience features, and power outlets for mobile electronics all increase the demand for power.

But AGMs can cost 40 to 100 percent more than highly rated conventional batteries. Consider buying one if you sometimes don’t use your vehicle for long periods and the battery loses its charge. An AGM battery can better tolerate a deep discharge, and it is more likely to fully recover if it is accidentally drained.



Check Our Car Battery Ratings Here

Get the Right Fit

Batteries come in a variety of sizes. It’s important to choose the right one to ensure that it fits securely and provides sufficient power. If the terminals are in the wrong place, your car’s cables might not reach or they might not fit securely. Check your owner’s manual or an in-store fit guide. Many retailers will install the battery free of charge.

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

Size 34/78 (dual terminal): Fits many large Chrysler vehicles and many 1996 to 2000 GM pickups, SUVs, and midsized and large sedans.

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

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

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


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

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

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

Size 75 (side terminal): Fits some General Motors midsized and compact cars and a few Chrysler vehicles.

How We Test

Our battery-life test is based on a standard adopted by the Society of Automotive Engineers (SAE). The test includes partially draining and then recharging each battery almost 3,000 times over a 15-week period, during which the battery must meet voltage and amperage limits based on real-life demands. The highest scorers maintained higher voltages and were able to withstand more cycles.

Our reserve-capacity test measures how long an auto battery can supply power if the charging system fails or if you leave your headlights or accessories on. We consider 1½ hours of power to be average. Higher-scoring models can supply power well past 2 hours.

Our cold-cranking amps test measures the current available at 0º F and is the primary indicator of cold-climate performance. Our CCA test is based on more realistic charging voltages and amperage demands than manufacturers’ tests, and our results show each battery’s relative cranking power, regardless of manufacturer’s claims.

Features and Accessories

These can help you get the most out of your battery and keep it in top working order for longer.

Car Battery Brands

Most aftermarket car batteries sold in the U.S. are made by three companies that build them for retailers: Johnson Controls, which supplies more than half of the market; Exide; and East Penn. They are sold under various names and built to the specifications of retailers, so performance can vary. Most stores will test, install, and match a battery to your car’s needs. Here are the major brands and where they are sold.

AutoCraft: Available at a variety of Advance Auto Parts stores across the country.
Bosch: Available at Pep Boys.

DieHard: Available at Sears and Kmart automotive centers.

Duralast: Sold at AutoZone. 

EverStart: Available at Walmart stores.

Interstate: Available at a number of auto parts stores, repair shops, and online. 

Napa: Sold through Napa auto-parts stores.

Super Start: Available through O'Reilly Auto Parts stores.
Consumer Reports is an independent, non-profit organization dedicated to helping consumers. We make it easy to buy the right product from a variety of retailers. Clicking a retailer link will take you to that retailer’s website to shop. When you shop through retailer links on our site, we may earn an affiliate commission – 100% of the fees we collect are used to support our mission. Learn more. Our service is unbiased: retailers can’t influence placement. All prices are subject to change.