Showing posts with label pre-charged nimh. Show all posts
Showing posts with label pre-charged nimh. Show all posts

Yuasa Enitime PLUS AA 2500mAh Pre-Charged Rechargeable Batteries (4-Pack). HIGHEST Capacity among Pre-Charged Batteries Review

Yuasa Enitime PLUS AA 2500mAh Pre-Charged Rechargeable Batteries (4-Pack). HIGHEST Capacity among Pre-Charged Batteries
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I was excited when I heard about those Yuasa EniTime PLUS AA 2500mAh Pre-Charged Rechargeable Batteries, because they are supposed to offer the highest capacity among pre-charged AA cells (note that SANYO has announced the 'eneloop XX' 2500mAh AA cells last year, but those are not yet available outside of Japan). Yuasa is a major manufacturer in rechargeable batteries. Previously I have had good experiences with Rayovac Rechargeable Hybrid NiMH Batteries which are actually made by Yuasa, so I fully expect those EniTime Plus cells to deliver as promised.
First warning sign: right out of the package, the terminal voltages of those EniTime PLUS cells were all slightly below 1.20V, which means they are nearly exhausted. When I tested them using my old La Crosse BC-900 charger/analyzer, the average remaining charge was just 12mAh! That means the claim of "Pre-charged and ready to use immediately" is completely false. It also makes me wonder whether those are really low-self-discharge type as advertised.
Subsequent testing result, however, was more promising. After the first recharge/discharge cycle, the average capacity improved to 2402mAh. This capacity remained the same in following cycles. This seems to suggest that they are indeed LSD cells, because ordinary NiMH cells typically take 3-4 cycles to slowly approach their maximum capacities.
The measured average capacity is 4% lower than the advertised rating of '2500mAh' (on each cell it actually says 'Min 2300mAh'), which is within acceptable tolerance. However, other name-brand LSD cells I have tested all have their measured capacities HIGHER than rated. For examples:
- Sanyo Eneloop AA: rated '2000mAh typ', measured 2100mAh (5% higher)
- GP Recyko AA Batteries: rated '2100mAh typ', measured 2230mAh (6% higher)
It will take a few more months for me to determine the long term self-discharge rate of those EniTime Plus cells. In the mean time, I can only give this product a neutral rating (meaning "It's OK"). This is because although it offers a relatively high capacity of 2400mAh, it is currently priced nearly twice as much as other LSD cells (you can get 8 GP Recyko AA cells for the price of 4 EniTime Plus). Also as a matter of principle, I rather give my money to companies that promise less but deliver more, instead of ones thae promise more but deliver less.

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Yuasa Enitime batteries are pre-charged and ready to use at any time. The ready to use technology is designed in Japan. Unlike regular rechargeable batteries, Enitime batteries have low-self discharge rate. Once fully charged, Enitime will retain 80% capacity after 1 year and ready to use at any time. Yuasa Enitime AA batteries provide superb amounts of clean, fresh energy to any device that uses AA batteries. Rechargeables save the environment because there is no need to throw them out when they are depleted. Ni-MH batteries such as these can be recharged fully or partially up to 1000 times without experiencing "memory effect". Excellent for high drain devices such as digital cameras, game consoles, toys, audio cd players, etc. GS Yuasa Corporation has long been a leading manufacturer of motorsports batteries, and also makes premium, high-quality consumer rechargeable batteries. GS Yuasa was formed in 2004 by a merger between Yuasa Battery and Japan Storage Battery, to form one of the largest and most reliable manufacturers of all types of rechargeable batteries.
Recommended to use with Hitech iC-108UL Smart Quick Charger (charger not included). Please visit our Storefront to view a complete line of Yuasa Ni-Mh AA and AAA batteries.

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Duracell Value Charger With 4AA Pre Charged Rechargeable Nimh Batteries, CEF14DX4N Review

Duracell Value Charger With 4AA Pre Charged Rechargeable Nimh Batteries, CEF14DX4N
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This package (CEF14DX4N) includes four new Duracell 'Pre Charged' NiMH AA cells, plus a simple charger. The batteries are similar to the Sanyo eneloop low-self-discharge cells. In fact, based on their identical 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.
The 'value charger' (CEF14) included here, however, is not a good value because:
1. It is a timer-based dumb charger, meaning that it doesn't detect when cells are full charged. It simply charges at 360mA for 6 hours and turns off. You have to wait until your cells are fully exhausted before recharging, otherwise they will be over-charged. With a 'smart' charger, you may choose to top-off your rechargeable cells any time.
2. It can only charge either 2 or 4 AA cells in pairs. This is very inconvenient if you have appliances that require odd number of cells.
3. It can only charge two AAA cells, and you cannot charge any more AA cells at the same time.
My advice is to get the CEF23DX4N package for just a few dollars more (*). It comes with four Duracell Pre Charged cells (2xAA + 2xAAA), but the included charger (CEF23) is far superior in every aspect. It even operates from your vehicle battery, and doubles as an USB charger, too.
[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.
[Update on Feb 15, 2010]
I have confirmed that the new Duracell 'Value Charger' has several improvements over the old model:
- Works from 100-240V AC (instead of just 120V AC)
- Able to charge 4 AAA at a time (instead of just two)
- Semi-smart charge termination (stops when BOTH cells are fully charged)
The only remaining drawback is thet it charges in pairs only.
(*) [Update on Oct 7, 2010]:
Duracell has discontinued the excellent CEF23 charger (at least in the US) last year. So prices for the remaining inventory have skyrocketed. If you need an inexpensive charger that can handle individual cell, consider the Sanyo eneloop MDR02 2-cell charger.

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Duracell Value Charger with 4AA Pre-ChargedRechargeable NiMH Batteries - CEF14DX4

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