In A Nutshell
Overall, the best rechargeable AA battery is the Eneloop Pro (aka Sanyo XX Battery Powered By Eneloop). These batteries hold their charge for 12 months. They also have a high energy capacity (2500 mAh), and they perform better than similar high-capacity AAs (see my article for more information).
Another good rechargeable AA is Maha’s Imedion battery, which is cheaper than the Eneloop Pro (about $5 less for a pack of 4). Imedions are also low-discharge, high-capacity batteries, but they do not perform quite as well as the Sanyo XX (see this reviews for the details on their performance).
Today, the best rechargeable batteries are the “low self-discharge” Nickel-Metal Hydride (Ni-MH) cells. These low-dischrage batteries have a lot going for them: they come fully charged (like alkaline batteries), and they can hold their charge over many months (unlike regular Ni-MH rechargeables). Because they can hold their charge for so long, they are suitable for low-drain devices like remote controls and flashlights. They are also ideal for use in high-drain electronic devices like digital cameras, where they out-perform alkalizes.
So, basically, these “low self-discharge” Ni-MH batteries offer the convenience and shelf-life of alkalines, and the high-drain performance of older Ni-MH batteries.
Generally, the best low self-discharge batteries are made in Japan (the others are made in China), these are: Sanyo’s Eneloops, Duracell, Energizer and Sony. The Eneloop Pro batteries from Sanyo definitely hold their charge the longest, and they are my top recommendation. I review the batteries in more detail below, and review some of the best battery chargers at the end of this article. I do not recommend the Energizer or Duracell rechargeable batteries — these name brands seem to produce inferior rechargeables, perhaps to protect their sales of alkaline batteries.
Eneloop Rechargeable Batteries by Sanyo
Better designed than other rechargeables, Eneloop batteries have become a best-seller for Sanyo. Eneloops can be recharged up to 1000 times, and they will retain their charged capacity even after 6 or 12 months of storage. After 6 months, they retain 90% of their charge. After 12 months, they retain 85% of their charge (when stored at 20 degree Celsius). Sanyo recommends keeping the batteries in a cool location to maximize charge retention.
The AA-sized Eneloops are rated at 2000 mAh, and the AAA-sized Eneloops are rated at 800 mAh (mAh stands for “MiliAmp hours” — a unit that indicates how much energy a battery can hold.)
The charge times are as follows: AA Eneloops charge in 230 minutes, and AAA Eneloops charge in 135 minutes.
Eneloop batteries are available at Amazon in 8 packs, and 16 packs and 32 packs. They are also available with a charger: 8 Eneloop Batteries with a Charger. Note that these links to the second-generation 2000 mAh eneloops.
You can also get a special edition Eneloop Glitter pack, which features multi-colored Eneloops.
Eneloop Pros (or Sanyo XX Battery Powered By Eneloop)
Sanyo has released a new version of the Eneloop, called the Eneloop Pro (in Japan) or Sanyo XX Battery Powered By Eneloop (in the US and Europe). The Eneloop Pro battery has a capacity of 2500 mAh — which is 500 mAh more than the regular Eneloops.
The Best Battery Chargers
How about some good battery chargers to go with these batteries? The chargers featured below are some of the smartest out there — they have built-in protection to prevent overcharging or undercharging. They can also handle most battery sizes.
LaCrosse Technology BC-1000 Alpha Battery Charger
The LaCrosse Alpha BC-1000 Charger has sophisticated monitoring circuitry that controls the charging process, and it is also capable of “renewing” batteries by running fully-controlled discharge-recharge cycles.
The charger shows battery voltage and charge status on its digital display. It has four separate charge channels so you can charge one, two three or four batteries at a time – even on individual charge programs. This allows you to test one battery while charging the others. It comes with four AA and four AAA batteries, four battery adapters (which convert AA sized battery to C and D sizes) and a carry case. Note, however, if you want to charge C or D size batteries, you’ll want to get the Ansmann chargers below.
You can get the LaCrosse BC-1000 Alpha Charger at Amazon for about $60, and you can find the BC-700 Charger available for around $36 (this is essentially the same charger but does not include bonus items the four AA & AAA cells, plus the four C + D-cell converters).
PowerEx MH-C9000 WizardOne Charger-Analyzer
This newly released charger could be a serious rival to the LaCrosse charger — we will post a full review soon.
The PowerEx MH-C9000 is available at Amazon for about $50
Maha PowerEx “Ultimate Professional” Charger
The Maha’s Ultimate Professional Charger almost lives up to its hyperbolic name. This compact charger can charge any combination of 1 to 8 batteries. You can mix and charge AA, AAA, C and D sized cells at the same time on individual charging circuits. Each battery size also has its own fixed contact charging points (i.e. not a spring). An LCD display shows charging and conditioning status of each rechargeable battery.
Like the Ansmann chargers, Maha’s chargers can restore batteries to their optimal performance level by repeatedly charging and discharging them. It also has intelligent charging technology and overcharge protection. It also comes with an international AC adapter, and short-circuit protection.
It is available from Amazon for around $83.