Car battery prices aren't a reliable indicator of car battery quality. For example, if you're a Costco member, you have access to one of the best car batteries you can buy at an exceptionally low price. Costco's Kirkland Signature 12866 (Est. $85) aces all tests by a leading reviewer. It shrugs off blistering heat and bitter cold, and boasts a deep reserve capacity that's important if you accidentally leave your lights on. Even the priciest batteries can't do much better.
The warranty is just as fantastic: three years replacement/100 months prorated. That means you'll get credit toward a new one, just like the top-rated DieHard Advanced Gold 50778 (Est. $165) covered in our Best Car Batteries section. Owners say Costco honors the warranty with no questions asked, but several super-satisfied customers have never had to use it. Some say they got eight or even 10 years and counting of car battery life out of a Kirkland battery.
The trade-offs: You'll need a paid membership to Costco (Est. $55 per year), and you'll have to install the battery yourself or find someone else to do it.
As with all brands, Kirkland's quality varies from size to size. The top-rated 12866 is a Group 65 battery for large Ford cars, trucks and SUVs. Other sizes of the same battery lag just a bit, but all prove average or better in tests.
Runner-up EverStart Maxx-35N (Est. $105) might be more convenient: It's sold at Walmart, where batteries are installed for free. The EverStart performs nearly as well as the Kirkland in tests. This is a Group 35 battery sized for Japanese imports -- Honda, Nissan, Subaru and Toyota -- but other EverStart sizes perform well, too. Interestingly, despite its "N" (North) label, this battery has a fairly modest CCA rating of 640. In tests, it starts just as strongly in freezing temperatures as batteries that claim 850 CCAs, including the Kirkland.
However, car battery life might be a concern. One owner reports at Walmart.com that three of these batteries failed within three frigid months this winter. Some other users complain that the EverStart Maxx-35N died right at the end of its three-year replacement warranty; there's a two-year prorated period after that. Two say the car battery leaked battery acid. One recommends the EverStart only if you're getting rid of the car within three years; "Otherwise, get something else," he says.