Panasonic’s Eneloop BQ-CC55, our favorite charger for AA and AAA rechargeable batteries, is sleek, compact, easy to use, and plugs directly into a wall outlet.

Q. I just opened my battery-operated alarm clock and found a badly corroded AA battery. Even though the date on the battery read MAR 2014, it was covered in white crystals.

These alkaline AA batteries won't last as long as some of the more premium brands, but they do have one thing going for them: they're very cheap. Coming in at around half the price of the next ...

We thought so. Listen up: We tested 15 AA batteries—the type typically used in digital cameras, flashlights, toys, radios, and remote controls—and found differences in performance and cost.