Product Description

Sony's newest rechargeable battery technology seeks to bridge the gap between regular alkaline batteries and NiMH rechargeable batteries. Cycle Energy rechargeable batteries do not require initial charging and have a very low self discharge rate. They maintain 85 percent of their charge after one year and can be recharged up to 1,000 times. This new technology offers consumers the convenience of a ready-to-use rechargeable battery that is longer lasting and environmentally friendly.

Product Details

• Amazon Sales Rank: #718 in Consumer Electronics
• Brand: Sony Batteries
• Model: NH-AA-B4K
• Released on: 2007-04-01
• Dimensions: 4.50" h x 2.50" w x .50" l, .10 pounds
• Battery type: NiMh

Features

• New improved NiMh rechargeable battery technology
• Already charged and ready to use
• Stays 85% charged after 1 year of storage
• Recharge up to 1000 times
• Battery Capacity: 2000 mah

Customer Reviews

The best battery.
I am an electrical engineer, and I have tested many, many batteries. The Sony CycleEnery batteries are the best batteries in the world. No other battery has performed as well for me. I highly recommend this battery above all others.

There are two things that make the Sony CycleEnery battery perform so well:

First, if you weigh the Sony battery on a scale, you will find that they are several grams heavier than any of the other brands. This means that there is more material inside, which yields a higher battery life span.

Second, the voltage curve of this battery stays above 1.2 Volts throughout the majority of its life span. The reason this is important is that most electronic devices, such as digital cameras, stop working once the voltage goes below 1.1 Volts. Normal NiMH batteries can have extremely high mAh ratings of 2500 or more -- but you can't actually make use of all those mAh's because the voltage drops below 1.1V relatively early -- this is not the case with the CycleEnergy. Sony has done something to keep the voltage up at 1.2V, so even though the battery is only rated at 2000mAh, they last much, much longer than normal NiMH batteries. I usually get 2-4x the life span out of CycleEnergy batteries, compared to normal NiMH (even the Sony ones!).

To summarize -- these are the best rechargeable batteries on the market right now (2008).

Regards,

~Chris Sebastian

Pretty good Batteries
I got this set in addition to Sony 2500 mAh AA Rechargeable Nimh Batteries. This set seems to work better than Sony 2500mAh batteries.

Excellent batteries
They really last a lot. Other batteries that I have do not hold charge for a long period.