Tuesday, 1 March 2011

Rechargeable Batteries


[Updated 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. Duracell Pre Charged Rechargeable NiMH AA Batteries, 4-Pack

[Updated 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.

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.

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.

Pros:

-For a rechargeable battery, they do 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. I use it everywhere, portable speakers, Wiimotes, toys, Panasonic, Dect 6.0 phones, 2-way radios...

-No need for a special charger. You can use your existing NiMh charger.



Cons:

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

- It has been several years and still the price hasn't really come down.



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


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