Rechargeable batteries are better and cheaper than you remember, and all the name-brand offerings will hold a charge for months and cost less than a nickel per charge over their entire life. Despite running our battery analyzers for over 1,000 hours, doing more than 20 hours of real-world tests, and literally driving three top brands considerably harder than recommended, our tests showed only a few small differences between the top brands. If you’re looking for AA batteries, the Energizer Recharge line of batteries ekes out the best performance for the price, but Eneloop AAs shouldn’t be ignored if you can find them on sale. For AAA batteries, AmazonBasics AAA Rechargeables are generally the best deal, but performance was nearly identical to AAAs from Eneloop, Energizer, and Duracell, so just get whatever’s cheapest when you need them.
The Energizer Recharge Universal AA batteries performed well at each step of testing: initial capacity, capacity after four dozen charges, self-discharge, and high-drain RC car racing. In raw capacity, Energizer had 30 percent more energy storage per dollar than the Panasonic Eneloop AAs, so your devices should run a little longer between recharges. In the first few cycles, that came to average of 1,888 milliamp hours (mAh) or 2.3 watt hours (Wh) of discharged capacity. When we cycled the batteries—discharged and recharged them, again and again—to show how they might handle once-a-week charging for a year (or once-a-month charging for four years); both the Energizers and Eneloops had virtually the same available capacity as when we started. This means that even after four dozen charges, we’d need more precise equipment to quantify any changes in performance and you shouldn’t notice a difference in day-to-day use.
Going beyond bench tests, we soldered six batteries together to run the motors of a high-powered RC car around a competition track. Though you’ll never drain batteries as quickly at home—and please don’t try!—the high-powered nature of our test cars was a perfect stress test for our unsuspecting batteries. Our haphazard Energizer battery pack lasted 11:28, about half a minute longer than the Eneloops. This wasn’t quite as long as the 15:52 that new, higher-capacity Powerex Precharged batteries managed, but the Energizers are around a dollar cheaper per battery, so they’re still the better overall deal.
Finally, we like that the Energizers are readily available for a fair price when you run to a brick-and-mortar store (like Target) last minute. You can stock up online for an even better deal, but in-store availability is important for batteries, because when you need batteries, you don’t always have the luxury of waiting a few days or weeks for shipping. And, for what it’s worth, the Energizer Recharge Universal line contains 4 percent recycled material recovered from hybrid car batteries, so they should be a bit less harmful to the environment than other options.
Eneloop batteries may have a loyal following, but the Energizers performed a little better and are typically cheaper. But if the Energizers are out of stock or cost more than the brick-and-mortar retail price of around $2.50 each, get the Panasonic Eneloop AA 2100 Cycle Rechargeable Batteries instead. Even though their performance was a bit short of the Energizers’s in most of our tests, it wasn’t by much. Out of the box, the more expensive Eneloops averaged around 5 percent less capacity over their first three discharges—1,849 mAh (2.2 Wh) compared with the Energizers’s 1,888 (2.3 Wh). Track run time of both brands was pretty similar when we modified them to race our competition-level RC car: Energizers bested Eneloops with an extra 29 seconds, 11:28 to 10:59.
But the Eneloops did win decidedly in one test—after nine months on the shelf, our sample Eneloops still had an average of 82 percent of their charged capacity available, compared with just 71 percent available from the Energizers. In a single-battery flashlight like this one, that could mean an extra 10 minutes of light. When taken together, our tests don’t point to either brand being conclusively better than the other. Still, the Eneloops regularly cost 25 percent more, and that’s not really worth it to most people just for slightly extended shelf life.
If you need rechargeable AAA batteries, you should buy the AmazonBasics, or really just whatever reputable brand is the cheapest when you need them. We performed our standard bench tests on the leading AAA batteries, and even subjected them to advanced headlamp-and-watermelon tests, and still found no statistical difference in their initial capacity, their capacity after 50 cycles, or how they handled a common use like powering a headlamp.
When we measured initial capacity by charging and discharging each battery three times and averaging the results, there was only an 8 percent difference between the capacity of the best and worst brands. In this case, an 8 percent spread is basically nothing. When we charged and discharged them another four dozen times—about 200 hours each—we also found that there was no drop in performance, or difference between brands, after the 50th cycle. We also tested which battery powered our favorite headlamps brightest and longest. After six hours, all four brands were dimming at a similar rate but still just barely lighting the way. It was long enough and close enough that the test ended in a tie.
We always like it when we can provide a simple, clear recommendation for what to buy, but the truth is that AAA rechargeable batteries have reached commodity status—the name brands are largely interchangeable for everyday uses like powering remote controls, wireless computer accessories, or small toys. We don’t recommend buying knockoffs or discount brands, but AmazonBasics, Energizer, Eneloop, and Duracell will all serve you well. Stock up when you find a good deal, but otherwise just buy what’s available when you need them.
If you need to get a charger anyway, we recommend buying the Panasonic Advanced Individual Cell Battery Charger with four Eneloop batteries. As long as the batteries you want to charge are standard NiMh rechargeables, the brand you put in the charger doesn’t matter. We spent some time looking over the competition, including a newer charger from Panasonic, but this is still our favorite for most people because it’s accurate, safe, and completely automatic. You can mix and match AA or AAA batteries (of different brands and capacities too) in odd or even numbers and still end up with happy, healthy batteries. Even though we didn’t choose the included Eneloop batteries as our top pick, they’re certainly a good value when bundled with the charger for less than $20 total—and for some reason, the charger is almost always cheaper when sold with batteries than when sold alone.
Table of contents
- Why you should trust us
- Who needs this, or why you should switch to rechargeables
- How we picked
- Testing methods and results
- Care and use
- Long-term test notes
- What about other battery sizes?
- Are AmazonBasics batteries just rebranded Eneloops?
- The competition
Why you should trust us
We clocked over 20 hours of research, ran our battery analyzers for more than 1,000 hours over the past year, and came up with some unique real-world tests, just to figure out which rechargeable battery is worth the couple bucks they normally cost. That’s on top of The Wirecutter’s hundreds of hours of research experience with batteries in general.
When the technical questions get too technical, we head over to our consulting electrical engineer, Lee Johnson. For an earlier update to this guide we spoke with David Hobby of Strobist about the demanding battery needs of professional photographers.
Who needs this, or why you should switch to rechargeables
Our top AA pick packs the equivalent of three or more times the capacity of a cheap disposable battery into a single charge. We know that rechargeable batteries haven’t always performed consistently or well, but the latest technology—LSD NiMH—can hold a much larger charge, retain it for much longer, and recharge more times than what was possible only a few years back.1 If you gave up on rechargeables because they didn’t seem reliable or have a high enough capacity, it’s time to take a fresh look.
Since Sanyo (now Panasonic) Eneloop batteries effectively launched the modern rechargeable in 2005, its line tripled capacity and doubled cycle life—the number of recharges a battery can take without degrading too much. But a bigger breakthrough than capacity or cycle life is the incredibly long shelf life of the latest generation of NiMH batteries. Any batteries marked “pre-charged,” “low self-discharge,” or “LSD” will retain their charge for potentially years, not just months. Though there was a time when Eneloop had the only reliably long-lasting batteries, this is no longer the case. We put shelf life claims to the test and found that even after nine months on the shelf, all our batteries still had more energy left in them than any disposable AA battery has fresh from the factory. So having a bad experience with Duracell, Energizer, or another brand several years ago doesn’t mean you should write them off today.
That makes LSD batteries practical for emergency kits or other instances of infrequent use. Michael Bluejay’s Battery Guides have a wealth of information on the underlying technology and the history of its improvements, and he still regularly updates with additional testing.
In addition to technology improvements, the price of rechargeables has come down considerably. Even after including the cost of a new charger, your first set of eight AA batteries will pay for themselves in five to six recharge cycles compared with buying most name-brand disposables. And the benefits go beyond your wallet: Globally, over 10 billion alkaline cells are made every year (PDF), and roughly half are purchased in the US (PDF). That’s an average of 47 batteries per US household per year. Over four years, that would mean 12 rechargeable batteries take the place of 188 disposables—not a bad way to save some money (and the environment).
The only persistent drawback to rechargeables is that they still take a long time to recharge. Properly charging batteries takes time if you want to preserve their long-term performance—about eight hours for our AA pick. Technically, the faster you charge your batteries, the less life you’ll get out of them, though with modern batteries and chargers, the difference is likely negligible. There are many “fast chargers” available, but we don’t recommend them, as they degrade rechargeable battery life.
Instead of a faster charger, we recommend buying an extra set of batteries. Figure out what device takes the most batteries and buy that many extra. If you always keep the extras charged and sitting next to—not in!—your charger, they’ll be there when you need them. Rotating batteries this way is like having a perpetually stocked supply without going to the store.
How we picked
Batteries don’t require hours assessing industrial design or critiquing the user interface. They’re pretty straightforward, and they have to match a fairly precise set of dimensions. We wanted to find the best, most quantifiable value—a reliable mix of capacity, life, price, and availability.
There are a handful of different battery technologies out there right now, but the only ones that will truly replace your alkaline AAs are nickel-metal hydride AAs, commonly abbreviated as NiMH. (You can pronounce it “nim” and save some trouble.) Specifically, look for new NiMH batteries that advertise “low self-discharge,” “LSD,” or even “Precharged!” that will hold a charge for months or years as opposed to mere weeks.
Most batteries are advertised based on their capacity and cycle life. Capacity, generally measured in milliampere-hours (mAh) and also noted in our guides as watt-hours (Wh),2 will give you an idea of how long one battery will last compared with another. Cycle life is supposed to tell you how many times a battery can be charged and discharged, but the number most manufacturers advertise is pretty useless for normal people—it’s a number measured in idealized conditions that don’t really match reality.3 Of course it’d be best if both capacity and cycle life were as high as possible, but due to the way batteries are made, improving capacity comes at the expense of cycle life and vice versa.
Some simple math shows why we don’t buy into advertised claims for the number of recharges, also known as cycle life. If an Eneloop were charged once a week, it would be 38 years until it reached its advertised life of 2,000 cycles, or over five years if charging it every day. The battery would die of old age before it hits that limit in real-world usage. We like that some of the Energizer promotional materials more realistically claim “up to 5-year battery life when used under normal conditions.” That seems more reasonable, and, when charged once a month, would still bring your cost per charge down to less than a nickel.4
In 2015, we considered all of this and chose eight AA brands to test. Though we ultimately recommended the Energizer Recharge Power Plus as the best deal, the Powerex Imedion was our runner-up, and the Panasonic Eneloop performed well but wasn’t quite as good a value. For our update in 2016, we revisited all three. Energizer changed the Recharge line of batteries to include 4 percent recycled content—an industry first—and we wanted to see how it would perform after the change. Specifically, we chose to test the Energizer Recharge Universal batteries that have the same stated capacity as the Panasonic Eneloops. Powerex told us they’d be discontinuing the Imedion batteries in favor of the newer, higher capacity Powerex Precharged batteries, so we brought those in for testing as well. Panasonic Eneloops stood in as something of a control group, the only tested battery that was unchanged in 2016.
To find the best AAA picks in 2017, we returned to our top AA brands, Energizer and Eneloop, and added Duracells because of their broad retail availability, and AmazonBasics because of their price and popularity online. All of these AAA batteries claim roughly the 40 percent of the capacity of our AA battery picks, or around 800 mAh total. Even though they hold less than half as much energy, some AAA batteries often cost about the same as AAs. According to price-tracking website Camelcamelcamel, an eight-pack of the smaller AmazonBasics AAA batteries averaged out to cost 5 percent less than the same number of Energizer AA batteries.
Testing methods and results
We found our picks through a mix of standardized measurements and real-world performance. Standardized measurements help us get hard, comparable numbers for how much energy a battery can hold, how long it can hold it, and how it performs after constant charging and discharging. That’s helpful for relative comparisons, but to relate that to the real world we also load batteries into flashlights, headlamps, RC cars, and anything else we can think of to demonstrate head-to-head performance variations.
Our first bench test was straightforward. We discharged four batteries from each brand so we’d clear out whatever charge was left from sitting on the shelf. Then we charged them and discharged them three times to average the results. The speed at which a battery is charged and discharged actually impacts the amount of energy it will store, so we standardized both rates to match the gentle rates that simple chargers often use. This meant charging at 500 mA (.5A) for AA batteries and 400 mA (.4 A) for AAA batteries. Depending on your use, you could be discharging batteries quickly (e.g., photography lighting, RC cars) or slowly (e.g., wireless keyboard). Because AA batteries are likely the choice for more-demanding devices, we discharged them at 1,000 mA (1 A) rate, but we stuck to just a 400 mA discharge for the smaller AAA batteries. With such a huge range of possible uses, it’s impossible for us to have data for all of them, but a standardized test like this is still useful for comparing batteries to one another.
AA Battery Capacity Tests
Stated Capacity (mAh)
Average Tested Capacity (mAh)
|Energizer Recharge Universal||2,000||1,887.91||94.40%|
When we picked our favorite battery charger, we didn’t recommend the Powerex MH-C9000 WizardOne because the extra button presses, settings, and information are all more than most people need day to day. But for our purposes, or for anyone who wants the maximum amount of customization in charging profiles, the WizardOne’s extensive feature list fits the bill neatly. (Powerex loaned us four units for our testing, and we’ve run each for hundreds of hours at this point.)
AAA Battery Capacity Tests
Stated Capacity (mAh)
Average Tested Capacity (mAh)
|Energizer Recharge Universal||700||734||104.86%|
We know that rechargeables have a bad reputation for losing their mojo a bit too quickly, so to simulate the same kind of charge and discharge cycle that you’ll do over the course of months or years, we kept cycling after our first few measurements. After 48 cycles—the interim charges and discharges of the AA batteries both done at 1 A to speed things up a bit—we measured the capacity again using the same technique we started with. Incredibly, there was no conclusive difference after the 49th charge. The most extreme changes were just 2 percent less in some AAs, and 11 percent more in some AAAs. If we had more advanced equipment maybe we’d find some small changes, but what our results show is that after four dozen cycles you shouldn’t notice any difference in the performance of your batteries due to overuse. Of course we can’t speed up time or simulate how each brand will do three or four years out—time heals all wounds and drains all batteries—but the actual charge cycles certainly won’t be what does them in.
One of the biggest differences in today’s rechargeable batteries compared with the original NiMH batteries common 10 to 15 years ago is their ability to hold a charge for long periods of time when sitting on the shelf. These batteries are said to have low self-discharge, but are also advertised with other terms like LSD or as precharged. The marketing materials will often tout impressive numbers, like having 80 percent of their charge after one to three years. After an update in 2015, we charged fresh samples of our top battery picks and set them aside. Imedion batteries, our previous runner-up pick, have since been discontinued, so we only compared the Panasonic Eneloops to the Energizer Recharge Power Plus cells, the latter of which were charged and stored before the change to 4 percent recycled material.
Nine-Month Difference from Charge to Discharge
Average Discharge per 30 Days
|Energizer Recharge Power Plus AA||–28.3%||–3.12%|
|Panasonic Eneloop AA||–17.9%||–1.97%|
Though neither the Energizers or Eneloops matched manufacturer claims, both did well enough that we’d trust them in an emergency kit, probably topping them off once a year. Eneloop loyalists can hang their hats on the details though, because even though the Energizer AAs had a respectable 71 percent of their charged capacity still available, the Eneloops cleaned their clock with an average 82 percent available (the difference is equivalent to about 10 minutes of extra battery from a flashlight like this one). Those numbers are based on an average of four of each battery being tested, so the results are different enough to be significant, but not different enough to change our pick. We have more batteries—AA and AAA—charged and sitting on the shelf to test like this again in future updates.
Running all these bench tests gives us great data to decide which batteries perform the best, but let’s face it, that’s some pretty dense info. And most people don’t know how these numbers relate to how well their batteries will work day to day. In our previous update, we patiently waited for flashlights to burn down and measured the runtime of each battery.
Our flashlights worked with only AA batteries, so to test AAA batteries we switched over to our pick for the best headlamp, the Black Diamond Spot, which runs on three AAA batteries. We loaded four of them, each with a different brand of battery, and set about to drain them completely. Because it would take too long to stand around and wait for the lamps to run down, we strapped our headlamps to some stand-ins and let a camera observe them slowly dimming as the night wore on.
After almost six hours, the lamps were all dim enough that they wouldn’t do you much good on a hike, though they’d still be a little useful in a tent. As in our capacity and cycle tests, the AAA batteries all performed roughly the same, so we called this test a tie as well, and snacked on watermelon for a few days.
Flashlights and headlamps may be common uses for AA and AAA batteries, but they aren’t the most demanding. Nothing drains a battery quicker than an electric motor, so to try our AA batteries in a high-stress situation, we headed out to Trackside Raceway in Brookfield, Wisconsin, and spent a summer day in 2016 with owner Jamie “JT” Tennies. Trackside has an indoor RC race track that hosts national competitions in addition to its normal open track practices. These cars are serious, regularly going 40 mph, with brushless motors powered by high-quality lithium-ion battery packs—far too fancy for our purposes. Instead, Jamie soldered our sample batteries into a pack with high enough voltage to run our test cars around the track. For all the battery testing we’ve done recently, we literally had no idea what to expect. These batteries are not made to be worn down so quickly, and the electric motors aren’t made to run on this type of battery either.
To keep the driving style roughly the same, JT used each pack in turn to drive the same car around the track, and we stopped the time when the car didn’t have enough power to clear one of the track hills. We took bets on how long they’d last (we were guessing five minutes or so), and whether we’d start any fires (we considered it very possible). Five minutes turned to six, and at 10 minutes in, we started getting nervous about exactly how long our experiment would run. In the end, our little AA battery packs raced around the track for between 11 and 15 minutes each. All three brands, the Powerex Precharged, Energizer Recharge Universal, and Panasonic Eneloop, impressed us. And as we pulled each one out of our test car at the end of the run, we realized that though we didn’t start any fires, what we were doing wasn’t exactly safe—the surface temperature of one pack was 210 degrees Fahrenheit a minute or two after being (carefully) removed.
Because of the voltage characteristics of our packs, our car didn’t go as fast as when running on its normal lithium batteries. JT thought it was probably going about half its top speed, even on straightaways. But given that these cars are a lot beefier than what kids will play with from Radio Shack, the results prove that modern rechargeable AA batteries are up to the task of this kind of high-drain duty. Not surprisingly, the Powerex batteries, rated for roughly 25 percent more capacity, lasted the longest. We’ll give the silver medal to Energizer for staying on the road for an extra 30 seconds, but given all the variables of our setup, Panasonic might have eked it out if conditions were a little different.
Average Resulting Voltage
Resulting Surface Temperature
Care and use
With the right charger, your batteries will mostly take care of themselves. LSD NiMH batteries don’t need be kept in the refrigerator or freezer, you don’t need to drain them before recharging, and they don’t need trickle charging to hold power. If you use one of our recommended chargers, the only care they need is to be taken off when they’re done charging to avoid power leaking into and overcharging them.
Because our charger picks all measure each battery independently, you can mix different brands when charging and not cause any problems. On the other hand, you’ll want to keep battery brands matched when you’re using them to ensure similar levels of charge. A device will usually stop working once the battery with the shortest life dies.
Overcharging batteries will eventually lower their cycle life, which means you’ll need to replace them sooner. On the other hand, fast-charging batteries will eventually reduce their capacities, causing you to charge them more often. There are all sorts of technical reasons to not go too slow or too fast. If you’re into learning about that sort of thing, jump over to the charger guide to learn the basics. If you’re really into that sort of thing, you can wander off to more technical sites that will explain why Negative Delta V Detection and pulse charging are the way to go.
Long-term test notes
We used the Energizer Recharger Power Plus batteries in our mice and keyboards for most of 2016 without any problems or unexpectedly short run times. Because NiMh batteries have a different voltage curve than alkaline batteries, we have noticed that simple battery meters, like the one that warns of low battery on macOS when using an Apple Magic Mouse or first-gen Magic Trackpad/Keyboard, can be confused about how full they are. We’ve learned to ignore the low-battery warnings and to continue to use the same batteries for a couple more weeks—if not months. Overall, the charge capacity life of our picks should be three to four times that of a standard disposable alkaline, but no matter what brand you use, be prepared for charge meters expecting alkalines to behave a little funky with NiMHs.
What about other battery sizes?
Now that we’ve covered both AA and AAA batteries and found little difference in performance among the top brands, we’re considering testing rechargeable C and D batteries, but they’re much less common. And because rechargeable NiMh AAs have capacities and voltage curves very different from their disposable alkaline counterparts, many companies suggest and sell C and D adapters that let you use AA batteries in devices that normally require the larger sizes. The adapters (sometimes called spacers) work fine, but will give you much less capacity than the larger batteries of the same type. We haven’t tested our picks’ performance under such grueling circumstances, but we’ll keep it in mind for further testing.
Are AmazonBasics batteries just rebranded Eneloops?
All sorts of rumors exist about whether the factory that makes Eneloops contracts out to other brands, such as AmazonBasics, because of the sale from Sanyo to Panasonic. But no matter what corporate evidence someone wants to go dig up, our tests don’t agree.
The AA AmazonBasics powered our test flashlight for only 2 hours, 12 minutes compared with 2 hours, 45 minutes from the true Eneloops. Even in last year’s inconclusive camera flash tests, the AmazonBasics batteries strobed only 80 percent as many times before being completely run down. Though our tests of AAA batteries showed that the AmazonBasics are on par with their name-brand competitors, the AA version aren’t a great deal for most people—especially at a price of around $2.12 per battery.
Most batteries we tested did surprisingly well, and if we happened to see any of our top four on sale for $2.25 or less, we’d probably go ahead and grab them.
The new Powerex Precharged AA batteries performed well in all our bench tests, with 2,470 mAh (3 Wh) available for discharge of 2,600 mAh (3.1 Wh) of stated capacity. That’s over 25 percent higher than either of our picks in terms of raw capacity, but you’re really paying a premium for that extra energy. The new batteries are retailing for roughly a dollar more per battery than our top pick—a huge difference if you want to stock up. If you have a specific need for the extra capacity, and don’t mind the cost, we’re sure they’d be great. But they’re just not necessary for what most people need around the house.
The AA Duracell Rechargeables were the only batteries to have a higher available capacity than the packaging claimed—2,473 compared with 2,400 mAh—but they were in sixth place on our flashlight test, lasting just 2:43. Finding the current generation for sale anywhere other than Walmart is surprisingly hard, and their retail price averages about 45 cents more per battery than our pick.
The EBL 8-pack High Capacity 2,800-mAh Ni-MH Rechargeable Batteries are among the least expensive AA batteries we’ve found, and they had the highest available capacity in all our tests. At an average of 2,487 mAh (3 Wh), an EBL bests our pick by a good 15 percent. But because of the technological trade-off between capacity and longevity, we’re not willing to put much stock in their cycle claims: 1,200 in some places and 1,500 in others.
The Panasonic Eneloop Pro line is a higher-capacity, lower-cycle-life version of the AA Eneloops, rated for 2,550 mAh and 500 cycles compared with the standard 2,000/2,100. But an Eneloop Pro is the most expensive of our group, offering only 10 percent more available capacity than our pick despite costing about 25 percent more. Higher capacity and lower cycle life is important in some situations—photographers might want to in squeeze every flash they can between battery swaps. In general, though, this isn’t a good trade-off for most people and isn’t worth the premium price.
Special thanks to Jamie Tennies and RC Hobby and Raceway for soldering our test packs and giving us track time for our testing.
- Michael Bluejay's Battery Guide, September 10, 2015 ,
- What is a C-rate?, Battery University, December 2015
- Battery Building Blocks, Battery University, May 13, 2016
- Battery Chargers and Charging Methods, Electropaedia, November 2015
- Best Rechargeable NiMH Batteries for your Flash (Don’t Buy Eneloops...), Light & Matter, October 7, 2014 ,