Here are my recommendations for the best rechargeable AA batteries:

If you want the best energy capacity (2550 mAh) — get the Eneloop Pro (about $18 for pack of 4)

If you want maximum recharge capacity (2100 times) — get the 4th Generation Panasonic Eneloops (about $11 for pack of 4)

If you are on a budget don’t mind a little less performance from your batteries — get the Powerex AAs (about $10 for pack of 4)

Overall, the best rechargeable AA battery is the Eneloop Pro. They have a high energy capacity (2550 mAh), and they perform better than similar high-capacity AAs. They can only be charged 500 times (versus 2100 times for regular Eneloops). But most people will never charge their batteries that many times. For example, if you charged your batteries twice a week consistently, it would take 5 years to reach 500 charges.

Also worthy of consideration is the Powerex battery, which is cheaper than the Eneloop Pro. These Powerex are also low-discharge, high-capacity batteries (2400 mAh), but they do not perform quite as well as the Eneloop Pro (see this review for the details on their performance).

The Details

Today, the best rechargeable batteries are the “low self-discharge” Nickel-Metal Hydride (Ni-MH) cells.

These 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. However, they are ideal for use in high-drain electronic devices like digital cameras, where they out-perform alkalines. See this graph for a comparison:

Generally, the best low self-discharge batteries are made in Japan (the others are made in China), these are: Panasonic’s Eneloops, Duracell, Energizer and Sony. The Eneloop Pro batteries from Panasonic definitely hold their charge the longest, and they are my top recommendation. 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 Panasonic

Better designed than other rechargeables, Eneloop batteries have become a best-selling battery. Eneloops can be recharged up to 2100 times, and they will retain their charged capacity even after years of storage. After 6 months, they retain 90% of their charge. After five years, they retain 70% of their charge (when stored at 20 degree Celsius). Panasonic 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.

Eneloop Pros

The Eneloop Pro is a high-capacity version of the regular Eneloop cell. The Eneloop Pro has a capacity of 2500 mAh –this is 500 mAh more than the regular Eneloops. Their only potential downside is that they can be charged 500 times — not 2100 times like the regular Eneloops. However, on average most people will charge their batteries about 100-200 times over a 5 year period.

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.

PowerEx MH-C9000 WizardOne Charger-Analyzer

The PowerEx MH-C9000 is one of the more sophisticated NiMH AA battery analyzer/chargers available. It has excellent ratings on Amazon — an average of 4.6 out of 5 starts from about 300 reviewers.

The drawback is that the single-status LCD panel a long programming sequence makes it a bit difficult to use for multiple cells. If this is an issue for you, consider the Maha charger listed below.

The PowerEx MH-C9000 is available at Amazon for about $60.

Maha PowerEx “Ultimate Professional” Charger

The Maha’s Ultimate Professional Charger 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.

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 adaptor, and short-circuit protection.

It’s available from Amazon for around $110.