We also perused the company’s website, read user reviews and ratings, and (when applicable) ran the Amazon listing through Fakespot to confirm it was a reliable seller. Good reputation: We considered whether we had heard of the company or tested its products in the past.Informative interface: We required that every model have some kind of indicator (either a display screen or lights) to signal when the batteries were charging and fully charged.(You should still take your batteries out of the charger within a day of charging them, though.) Auto shutoff: We made sure the charger had a mechanism to automatically cut off power after the batteries are done charging, and when no batteries are inserted.Individual charging: We ruled out chargers that only let you charge your batteries in pairs, rather than single batteries or odd numbers.Chargers meant for more than four batteries are generally much bigger and more expensive, but they might make sense for people who use a lot of batteries simultaneously. Most AA and AAA batteries are sold in multiples of four, and most devices don’t require more than two at a time, so we think a four-slot charger makes sense for most people. Charges between four and eight batteries at a time: We only considered chargers that can charge either 1–4 or 1–8 batteries at a time.AA and AAA compatibility: We considered only chargers that can charge both AA and AAA batteries, because both are fairly common types of rechargeable batteries.NiMH (nickel metal hydride) compatibility: We made sure the charger was compatible with NiMH batteries, which have the latest technology and are the most common AA batteries-NiCd (nickel cadmium), lithium, lead, and zinc rechargeable batteries are far less common.