Rated the very best car battery in one top test, the DieHard Advanced Gold 50778 delivers outstanding performance whether it's sweltering or freezing outside; both are typically murder on batteries. But watch out: Some sizes of this car battery don't perform as well in tests.
Unbeatable performance in most sizes. Nothing beats the DieHard Advanced Gold 50778. It earns the highest possible scores in every test by a leading source: cold-weather cranking, hot-weather endurance and reserve capacity, or how long it will run with the engine off (such as if you accidentally leave your lights on). This is a Group 78 size made to fit large Chrysler and GM vehicles.
The Group 34 version -- labeled 50734 -- does just as well in tests, and the Group 94 version gets good owner reviews at Sears.com. However, the Group 48 size conked out halfway through the heat test and was rated the very worst battery in that evaluation.
Rugged design, strong warranty. This is an absorbed glass mat battery, which "typically makes for a more rugged and longer-lasting battery than a conventional battery," ConsumerReports.org says. It's a sealed, maintenance-free design, so you won't have to top off the water. The DieHard Advanced Gold 50778 carries a three-year warranty: If it won't hold a charge during that time, Sears will replace it. After that, there's a 100-month prorated warranty, so you'll get a credit toward the purchase of a new DieHard battery if yours fails.
Installation charge. The good news is, Sears charges $165 for this battery but you'll get a $33 discount if you trade in your old battery. The bad news is Sears charges $10 extra for battery installation, according to Sears.com. Plenty of other stores -- including Walmart, auto-parts chains and some garages -- will install your battery for free if you buy it from them.
For about half the price, the Kirkland Signature 12866 (Est. $85) performs almost identically in tests and has the same warranty. However, it's sold only at Costco, where you need a paid membership and they don't install batteries.
Editors here test 56 car batteries, including the DieHard Advanced Gold 50778. They review and rate each battery's life expectancy, cold-cranking amps (CCA) and reserve capacity, then assign an overall score and rank the batteries from best to worst.
Review: DieHard Advanced Gold 50778, Editors of ConsumerReports.org, April 2013
Don't just shop for car batteries by brand, cautions ConsumerReports.org in this free article. Jim Travers uses DieHard Advanced Gold as an example: It makes the best Group 65 size battery in ConsumerReports.org's latest tests and the worst in Group 48 size.
Review: Beware: The Best and Worst Replacement Car Batteries Can Be From the Same Brand, Jim Travers, April 26, 2013
3. Cars Direct
DieHard is one of seven car battery brands recommended here. CarsDirect.com says, "They last much longer than other batteries."
Review: The Best Car Battery Brand to Use for Lasting Performance, Andrew Kaufman, Nov. 6, 2013
The Group 94 size of the DieHard Advanced Gold battery earns five perfect 5-star customer ratings here. There's an odd lack of DieHard battery reviews, though; the other sizes get either no feedback or next to none.
Review: DieHard Advanced Gold AGM Battery -- Group Size 94, Contributors to Sears.com, As of February 2014