Product Details
Sony Cycle Energy AA Ni-MH Rechargeable Batteries (4-Pack)

Sony Cycle Energy AA Ni-MH Rechargeable Batteries (4-Pack)
From Sony Batteries

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Average customer review:

Product Description

SONY NH-AA-B4K CYCLEENERGY BATTERY BLISTER MULTIPACK (AA 4-PK) CYCLEENERGY BATTERIES; DO NOT REQUIRE INITIAL CHARGING; MAINTAINS 85% OF THEIR CHARGE AFTER 1 YEAR; RECHARGEABLE UP TO 1000 TIMES ; AA; 4-PK

Product Details

  • Brand: Sony Batteries
  • Model: NH-AA-B4K
  • Released on: 2007-04-01
  • Dimensions: 4.50" h x 2.50" w x .50" l, 1.00 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

so far so good4
Came charged out of the box, so far so good, but will know only in the long run.

Excellent batteries5
They really last a lot. Other batteries that I have do not hold charge for a long period.

The best battery.5
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