Sanyo claims that its eneloop batteries can be recharged more times than any of its competitors.
Their latest batteries, available in AA or AAA sizes, can be recharged up to 1,500 times. That's 500 times more than the original eneloop batteries, which launched in November 2005. Sanyo's claim of being number one is compared to other nickel-metal hydride batteries as of today.
The eneloop (named for the concept of "looping energy") is also well-known for its ability to hold a charge when not in use. These batteries incorporate some aspects of dry cell batteries, like the throw-away Alkaline, allowing them to hold 75 percent of their charge after three years. And in a nod to treehuggers, the batteries come pre-charged through solar power at Sanyo's manufacturing plants.
At the core of these batteries is a "super-lattice alloy" made of negative electrodes. Sanyo says it has made a couple improvements that keep the alloy from deteriorating, and the company has also packed more cells inside the battery thanks to a thinner, yet stronger outer casing. The result is a battery that costs 2.5 yen per use (2.8 cents) compared to 4 yen per use (4.5 cents) for conventional rechargeable batteries.
Now for the bad news: Though I haven't tried these batteries myself, the reviews I've read note that eneloops have a lower capacity than standard NiMH batteries. So while you may be able to charge the eneloops more times, you may have to charge them more frequently, especially for extended uses. If your device spends a lot of time on the shelf, however, the difference may be negligible.
In any case, Sanyo claims that 90 percent of eneloop users are satisfied with the product, and the reviews I've seen are positive. The latest upgrade should be well-received.
