Since AA and AAA are the most commonly used household batteries, we focused primarily on those sizes for this guide. To find the best ones, we scanned well-known retailers like Amazon, Home Depot, and Walmart to get a feel for the most widely accessible brands of rechargeable AA and AAA batteries. From there, we whittled down our list based on the following criteria:

• NiMH chemical composition: Nickel metal hydride (NiMH) batteries are the gold standard in AA and AAA rechargeables to date, so we focused primarily on this variety. However, lithium-ion (Li-ion) rechargeable batteries offer certain advantages in some cases, so we also tested them for people who need the extra voltage they provide (1.5 V compared with 1.2 V).
• Available in packs of four or eight: We recommend getting twice as many batteries as you actually need, so you can charge one set while the others are in use. (Just remember to take them off the charger once they’re charged to avoid damage.) Since our favorite charger can handle up to four batteries at once, for this guide we preferred brands offering packs of eight batteries (or four, so you can easily buy two packs at once).
• Rated to withstand at least 1,000 cycles: Some rechargeable batteries are rated to last hundreds of cycles — a battery cycle is one full charge and one full discharge. But in order to find those that can last the longest, we considered only those models with cycle ratings in the thousands. Keep in mind that your batteries will likely perform worse after a handful of years, regardless of the number of times you recharge them. But the number of rated cycles signals how long the battery was made to last.
• Marked “low self-discharge,” “LSD,” or “pre-charged”: All rechargeable batteries experience some amount of self-discharge, which means that as soon as they are fully charged, they start to lose a little bit of charge. So just because you fully charged a battery yesterday doesn’t mean it will still be 100% charged today. However, some batteries are designed to have a lower self-discharge rate than others, and they are marked as such. This feature can cost a premium, but we require it for every model we test because we’ve found that some low self-discharge batteries are still usable after several years, as opposed to months, in storage.
• High battery-capacity rating: Keeping in mind that a battery’s true capacity is often lower than the rating on the box, we wanted to restrict our search to options with high battery-capacity ratings. After considering the landscape of options, we gave preference to batteries with capacity ratings of at least 2,000 mAh for AA and 800 mAh for AAA. A higher battery capacity means more time channel-surfing with your TV remote, illuminating dark corners with your flashlight, and listening to groovy tunes on your Walkman.
• No more than $3 per battery: Since rechargeable batteries aren’t something most people use every day, and you don’t get significant improvements by paying more, we set a hard price cap of $3 per battery. None of the models we considered were cheaper than $1 per battery, and most cost right around $2 per battery.

We used the same criteria to select several less-common battery types to test, including Li-ion AAs, Li-ion AAAs, and NiMH AAAAs. We also tried a couple adapters that can turn any AA battery into a C or D battery.

In our latest round of testing, we performed a mix of technical and real-world tests to see how major brands of batteries performed in a variety of situations. First, to test the NiMH batteries’ average capacity, we used a Powerex MH-C9000 battery analyzer (now discontinued) to drain the batteries completely and then charge them completely, three times in a row.

We discharged and charged (cycled) the AA batteries at 1,000 mA, which is the recommended rate for batteries of this capacity. We then cycled the AAA and AAAA batteries, which have less capacity and should be cycled more slowly, at 500 mA and 300 mA, respectively.

We recorded the capacity (in mAh) measured by the Powerex after each cycle, and we calculated the average capacity over the three cycles. We then compared these numbers with the capacity ratings printed on the label, to see how our measurements stacked up against the company’s claims.

Next, to test the batteries’ long-term capacity, we cycled them 50 times and recorded the capacity (again, in mAh) measured by the Powerex after the final cycle. This number should be slightly lower than the average capacity from the first few cycles, since a battery’s innards deteriorate every time it’s charged or discharged, but we wanted to see whether any of the brands’ batteries suffered a significant drop in performance after dozens of cycles. (We performed the same tests with the Li-ion contenders, though we used a Tenergy TN456 charger instead of the Powerex, since the latter is incompatible with lithium-based batteries.)

To test the batteries in real-world situations — bringing our capacity tests to life, in a sense — we had them power a variety of household electronics simultaneously. We waited for them to die, one by one, and recorded how long each battery model lasted in each device. To see how the batteries handled low-power versus high-power drains, we made sure to test each model in at least two devices: one powered by a single battery and one powered by three batteries.

For instance, we popped the AA contenders into battery-powered alarm clocks, electric toothbrushes, colorful strobe lights, and/or essential oil diffusers (we decided to throw out the diffuser results since they were wildly different; some filled our rooms with tropical aromas for just a day or two, whereas one lasted a mind-boggling 352 hours). With the AAA batteries, we powered sets of twinkle lights, electric toothbrushes, pocket-size lanterns, and/or toy tugboats. Finally, we put the AAAA batteries to work in a slim stylus and penlight.

Like all batteries, rechargeables degrade over time, causing their capacity to decrease until they stop working completely. In past rounds of testing, we’ve conducted shelf-life tests of various NiMH rechargeable batteries, and we found that most can stay viable in storage for months (and even years, if marked “pre-charged,” “low self-discharge,” or “LSD”).

Shelf tests

To understand their degradation over time, we placed four batteries from five widely available brands in long-term storage (AA for nine months and AAA for 18 months), testing them before and after to see how much energy they lost while sitting on a shelf. Results are averaged.