Duracell Rechargeables StayCharged AA Batteries, 4-Count

[Update Aug 28, 2011]

The name of this product has been changed to Duracell Rechargeables StayCharged AA Batteries. As far as I can tell, those are the same batteries previously marketed as 'Pre-Charged'. In other parts of the world, those are also marketed as 'Active Charge'. They are stlll available in either 'white top' (made in Japan) and 'black top' (made in China) versions.

Amazon has combined the AA and AAA versions of those Duracell batteries into the same product page. So now I look like a fool who says the same things twice. Oh well...

[Previous update on Dec 24, 2008]

I was only half-right when I boldly proclaimed that "Duracell Pre Charged AA are rebranded Sanyo eneloop cells" in my original review. It turns out that the first batch of Duracell AA cells I bought from Amazon are made in Japan, and those are identical to eneloop (both mechanically and electrically). But lately I bought some more Duracell AA from a warehouse club. Those are made in China, and they are identical to the Rayovac Hybrid.

[Original review follows]

Judging from similarity of technical specifications and physical shapes of (+) and (-) terminals, I am convinced that the Duracell Pre Charged AA is actually SANYO eneloop AA underneath a different wrapper. Therefore all the good things you heard about eneloop apply to Duracell 'Pre Charged', too.

My own testing has shown that the capacity of eneloop AA cell is slightly above the claimed 2000mAh, and it is able to retain at least 85% of its charge after 5 months in storage. The Rayovac Hybrid AA starts with slightly higher capacity at 2100mAh, but it 'only' retains 80% capacity after 5 months. For all practical applications, both are equally good. Just pick whichever brand (Sanyo, Rayovac, or Duracell) is on-sale, and you can't go wrong.

One small problem with the Duracell 'Pre Charged' cell is that: it looked too similar to the well-known 'Copper Top' alkaline cell. So there is a good chance that people may mistaken it for a disposable cell. Personally, I prefer the distinctive-looking white case of the eneloop cell.

Pros:

-For a rechargeable battery, these batteries does not need to be charged before you use it for the first time; right from the packaging into your gadgets.

-They last a long time.

-Does not need special charger. You can use your existing NiMh charger.

Cons:

-You can confuse them with regular Duracells and mistakenly thrown away after losing charge.

-This later technology is still expensive.

I also like Eneloops by Sanyo. But they are not easily available at your local stores.

Buy Duracell Rechargeables StayCharged AA Batteries, 4-Count Now

[Update Aug 28, 2011]

The name of this product has been changed to Duracell Rechargeables StayCharged AAA Batteries. As far as I can tell, those are the same batteries previously marketed as 'Pre-Charged'. In other parts of the world, those are also marketed as 'Active Charge'. They are stlll available in either 'white top' (made in Japan) and 'black top' (made in China) versions.

Amazon has combined the AA and AAA versions of those Duracell batteries into the same product page. So now I look like a fool who says the same things twice. Oh well...

[Previous update on Dec 21, 2008]

I was only half-right when I boldly proclaimed that "Duracell Pre Charged AAA are rebranded Sanyo eneloop cells" in my original review. It turns out that the first batch of Duracell AAA cells I bought from Amazon are made in Japan, and those are identical to eneloop (both mechanically and electrically). But lately I bought some more Duracell AAA from a warehouse club. Those are made in China, and they are identical to the Rayovac Hybrid (see my scan in the Customer Images section). Note that the Rayovac Hybrid AAA has an average capacity of about 780mAh (compared to about 830mAh for eneloop AAA), so is not as good a value.

[Original review follows]

Judging from similarity of technical specifications and physical shapes of (+) and (-) terminals, I am convinced that the Duracell Pre Charged NiMH cell is actually Sanyo Eneloop underneath a different wrapper. Therefore all the good things you heard about eneloop apply to Duracell 'Pre Charged', too.

My own testing has shown that the capacity of eneloop AAA cell is slightly above the claimed 800mAh. The Rayovac Hybrid AAA is usually cheaper, but its capacity is slightly below 800mAh. Both brands are able to retain at least 85% of their charge after three months of storage. Just pick whichever brand is on-sale, and you can't go wrong.

One small problem with the Duracell 'Pre Charged' cell is that: it looked too similar to the well-known 'Copper Top' alkaline cell. So there is a good chance that people may mistaken it for a disposable cell. Personally, I prefer the distinctive-looking white case of the eneloop cell.

Read Best Reviews of Duracell Rechargeables StayCharged AA Batteries, 4-Count Here

I have been using these for a few months in my camera, Logitech Harmony remote, and in my Wii remotes and they have been great.

However, I was looking at batteries at Walmart today and noticed their new stock of Duracell Precharged batteries are being made in China and no longer have a white cap. They shoved the Japan made white cap batteries to the back of the shelf. This makes me think they are no longer Eneloops. I am a little nervous to buy another set of these as the only reason to make that switch in my opinion is to save money yet charge the consumer the same. This usually leads to an inferior product. The originals I have are made in Japan.

Anyway, maybe the battery review guru of Amazon will do a little comparison test of these new China made precharged batteries vs the Japan made batteries that seemed awfully similar to the Eneloops. I really hope the new version stands up to the old.

Want Duracell Rechargeables StayCharged AA Batteries, 4-Count Discount?

First, the disclaimer: There is no political motivation in this review. It is purely based on the findings of my measurement and facts. I hope no one should be offended.

I purchased three packs of these batteries. I found that one pack says "Made in Japan" and the other two "Made in China" in the back of package. Otherwise, the packaging is almost identical. There is, however, a very clear distinction on the battery itself. The Japanese made batteries have a white top while the Chinese made have a black top as shown in one of the photos I uploaded.

I was curious to see if there is a performance difference between the same line of batteries from different manufacturing plants. I have a La Crosse BC-700. So I put all three set into test mode, straight out of the package without any prior use. After 24 hours of measurements, the results are shown in the photos I uploaded.

The 8 batteries made in the Chinese factory averaged 790 mah. That is within 1.25% of the stated capacity. However, I found the variation among the samples is somewhat large, from 774 to 825.

The 4 batteries made in the Japanese factory averaged 834 mah. But more impressively, all samples were within the 832-838 range. This is an important characteristic because when you use multiple batteries in a device, the total capacity available is limited by the lowest one in the group.

I conclude that no matter where where these batteries are made, they at least meet expectation. With that said, I would prefer the "white top" batteries that are made in the Japanese factory. They are extremely consistent and offer higher capacity.

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