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Showing 1-10 of 7,819 reviews(Verified Purchases). See all 8,154 reviews
I have done extensive testing on the original eneloop rechargeable batteries since early 2007, shortly after they were introduced in the US. I have also tested the blue second-generation eneloop cells from the Costco eneloop package back in 2010. But this is the first time I have seen second-gen eneloop in white wrappings being sold in the US. With so much talk about counterfeit eneloop going around, I was understandably cautious when I purchased those SANYO NEW 1500 eneloop 8 Pack AA Ni-MH Pre-Charged Rechargeable Batteries.

I tested four of those cells, using my old La Crosse BC-900 Battery Charger.
- Right out of the package, their average remaining charge is 1568mAh, or nearly 80% of the rated capacity of 2000mAh. The spread is also very small, from 1558 to 1577mAh. This proves that they are indeed low-self-discharge type. (Date code on my cells says "11-01", or Jan 2011)
- After one recharge/discharge cycle, their average capacity improved to 2115mAh
- After two more recharge/discharge cycles, their average capacity leveled off at 2133mAh, or more than 6% higher than the rated capacity.

The above results are very consistent with what I have previously observed, while testing second-gen eneloop cells in the Costco package. Therefore I'm convinced that those are indeed genuine second-gen Sanyo eneloop cells. (See the scans I uploaded to Customer Images section, if you need to distinguish between old and new eneloop cells)

On the other hand, currently the prices of those new eneloop cells are about 25-50% higher than that of the original eneloop cells. So one may question: do the new eneloop cells offer sufficient improvement over the old, to justify the price different? Let's compare the following factors:

- Cycle Life: The 2nd-gen eneloop claims to "recharge up to 1500 cycles", while the original only claims 1000 cycles. This 50% improvement looks great on paper, but note that if you recharge your eneloop cells twice every week, it will take 10 years to reach 1000 cycles. So in real life, most average users will never notice the difference.

- Self-Discharge Rate: The new eneloop cells claim to "maintain 75% charge after 3 years", while the original only claims "80% after 2 years". Again, in real life most people will never notice the difference.

- Capacity: First-gen eneloop AA cells have "Typ 2000mAh, Min 1900mAh" printed on them, while 2nd-gen eneloop AA cells only say "Min 1900mAh". But in fact they have the same capacity rating of 2000mAh (typical) according to official Sanyo web site. My measured capacity numbers are actually around 2100mAh for both versions.

BOTTOM LINE:
Both the new and old eneloop cells are excellent products. You can safely mix and match them in any application, and probably nobody can tell the difference in the next 10 years. But in case you can't decide which version is a better value... Just flip a coin and pick one - you can't lose either way!

[Update on July 31, 2011]
Long term self-discharge data: I have tested a pair of new eneloop AA cells after 104 days sitting on the shelf (the batteries, not me). The average remaining charge is 88.7%. This charge-retention rate is slightly better than that of the original eneloop, but the difference is within margin of error for my experiment.

[Update on May 8, 2012]
Nowadays the 2nd-gen eneloop cells are generally priced lower than the original. So you should definitely get the newer version.

[Update on Apr 7, 2013]
Long-term self-discharge rate update: I just tested a set of 2nd-gen eneloop AA cells after two years in storage. They retained 1685mAh, or 84% of rated capacity. This is no difference from the claimed charge retention rate of 3rd-gen enellop (which says 85% after two years). See my following review on 3rd-gen eneloop:
http://www.amazon.com/review/R1Z4N7MRAH0BMX/
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288288 comments| 3,057 people found this helpful. Was this review helpful to you?YesNoReport abuse
I have been using Sanyo eneloop low-self-discharge NiMH batteries since beginning of 2007, and I'm completely satisfied with them. One thing I noticed is that newcomers to the rechargeable battery arena often have similar questions/confusions about eneloop. So here is my list of eneloop Frequently Asked Questions. This list is work in progress.

[Q1] My Sanyo eneloop AA batteries say '1900mAh' on them. Are they counterfeits?
[A] All eneloop AA cells (both original and second-gen versions) are rated for "Typ 2000mAh, Min 1900mAh" according to Sanyo. The confusing part is that 2nd-gen eneloop AA cell only has "Min 1900mAh" printed on it, even though the actual measured capacity is close to 2100mAh.
Simialrily, eneloop AAA cells are rated for "Typ 800mAh, Min 750mAh".

[Q2] Date code on my new eneloop cells says '10 01' (Jan 2010). Should I exchange them for newer batteries?
[A] Relax! Unlike ordinary NiMH cells, Sanyo eneloop are still perfectly good even after 5 years in storage. Once you recharge them, they will return to 100% capacity again.

[Q3] What is the difference between 'Pre-Charged', 'Hybrid', 'Stay-Charged', 'Active Charged', 'Ready to Use' and 'Ready to Go'?
[A] Those are all marketing terms for Low-Self-Discharge (LSD) NiMH batteries. Sanyo first used the term 'Pre-Charged' for Sanyo eneloop back in 2006. Rayovac used 'Hybrid', and so on.

[Q4] I just received some new eneloop batteries. Do I need to recharge them before use?
[A] You can use them right out of the package. However, eneloop cells are only charge up to ~75% when they left factory. So you can use a Smart charger to 'top-off' their charges. Do NOT do this with a Dumb charger because it will badly over-charge them.

[Q5] I thought I have to drain my batteries completely before recharging them?
[A] This is only necessary if you are using a timer-based dumb charger. With a smart charger, you can top-off your batteries anytime.

[Q6] Can I use other brands of chargers to recharge Sanyo eneloop batteries?
[A] Sanyo eneloop batteries can be recharged using any good-quality Smart charger designed for NiMH cells. But for longer battery lifespan, avoid ultra-fast (15- or 30-minute) chargers and Dumb (overnight) slow chargers

[Q7] What is the difference between 'Smart' and 'Dumb' chargers?
[A] A Smart charger monitors the voltage profile of each cell individually during charging, and stops when a charge-termination signal (negative delta-Voltage) is detected. This is the only way to avoid over-charging. A Dumb charge relies on safety timer to stop charging, or has no termination mechanism at all. This usually results in over-charging which is bad for battery lifespan.

[Q8] Should I stick to the Sanyo MQN06 charger packaged with most Sanyo packages?
[A] The MQN06 is semi-smart but has two issues: it charges in pairs (monitors the combined voltage of two cells), and the charging current is only 300mA. That means it take about 7 hour to recharge a pair of eneloop AA cells. Better choices include Sony Cycle Energy BCG34HLD and iGo 4-Position Charger.
[ Note: Charge time (hour) = Capacity (mAh) / Current (mA) ]

[Q9] What is the best charging speed for Sanyo eneloop?
[A] Choose a charger that gives you charge time between 2-5 hours. That means charging current of 500-1000mA for AA, 200-500mA for AAA.

[Q10] Isn't it true the best charging speed for NiMH and LSD-NiMH battery is the slowest?
[A] That is only true when using a dumb charger which blindly charges for 12-15 hours, so the current has to be below 0.1C (200mA for a 2000mAh cell) to avoid over-heating. For a smart charger, the current needs to be at least 0.2C to ensure proper termination.

[Q11] I always keep a set of ordinary NiMH batteries in the charger to keep them freshly charged. So why do I need LSD cells?
[A] You don't need to do that with LSD cells. Just charge up a spare set ahead of time and keep them in your drawer. Swap them in whenever needed, just as how you use disposable cells.

[Q12] Why should I buy those 2000mAh Sanyo eneloop instead of ordinary NiMH batteries that are rated 2500mAh or higher?
[A] All rechargeable NiMH AA cells rated 2500mAh or higher are susceptible to Rapid-self-discharge problem. Beware of off-brand batteries that claim '2900mAh' or higher. Most of them can't even deliver 2000mAh.

[Q13] Can I use eneloop in places with extremely hot weather?
[A] As a rule of thumb, every 10 degree C rise in temperature causes the battery's self-discharge rate to double. So although your eneloop cells can still function correctly, their shelf life will be reduced at high ambient temperature.

[Q14] Should I store unused eneloop batteries in the refrigerator to extend their shelf life?
[A] For ordinary NiMH cells, storing them in lower temperature greatly reduces their self-discharge rate so you can get longer shelf life. For eneloop cells it is hardly worth the trouble, because they can be stored for years at room temperature.

[Q15] Can I use eneloop batteries in cordless phones?
[A] Yes - as long as your phones (such as Panasonic DECT 6.0 cordless phones) are using individual AAA cells, instead of battery packs with special connectors.

[Q16] Do rechargeable batteries only go bad after they meet the number of charging cycles, or their lifespan is limited by time also?
[A] Capacity of a NiMH cell gradually deteriorates with number of discharge cycles. The 'lifespan' claimed by manufacturer is the number of deep-discharge cycles before capacity drops to 50%. This is done under tightly controlled test conditions, so in real life your result may vary.

[Q17] When rechargeable batteries go bad, do they also spill chemicals (like alkaline cells) or just won't hold a charge?
[A] Good-quality NiMH cells do not spill electrolyte as they gradually deteriorate. The only chance this can happen is when they are (a) severely over-charged at a high current, or (b) severely over-discharged, or (c) exposed to extreme heat.

[Q18] My baby swing calls for 4 D sized batteries. Do eneloop D spacers work well?
[A] You can use those in a pinch, but expect to replace/recharge your AA cells a lot more frequently than before. This is because the energy stored in an alkaline D cell is about 7-10 times greater than that in eneloop AA cell. See my following review for other options: SANYO Eneloop Spacer Packs with 2 AA with 2 D-Size Spacers

[Q19] My La Crosse BC-700 Battery Charger reports some eneloop batteries as 'null'. Are they defective?
[A] If a battery is over-discharged and its voltage drops below 0.5V, the La Crosse charger cannot detect it and so the display says 'null'. Charge your 'null' battery in a dumb charger for a few minutes, then the La Crosse charger will recognize it.

[Q20] I read on Wikipedia that there is an Eneloop 3rd generation battery (HR-4UTGB.) Are they worth getting over second generation?
[A] Panasonic (who bought Sanyo in 2009) claims that lifespan of 3rd-gen eneloop cells has been upgraded from 1500 to 1800 cycles. But keep in mind that even if you recharge your cells twice every week, it will take you nearly 15 years to use up 1500 cycles from your 2nd-gen eneloop cells.

[Q21] Are the new AmazonBasics Pre-Charged Rechargeable Batteries just rebranded 1st-gen eneloop cells?
[A] Not exactly. According to their mechanical features, they are most likely SECOND-gen eneloop cells. See my review for details: http://www.amazon.com/review/RLX50IR99K7PL/

[Q22] How do the new Duracell pre-charged Batteries ('2400mAh', 'Long Life Ion Core') compare to Sanyo eneloop or XX cells?
[A] Based on my testing, I believe the Duracell 'ion core' AA cells are actually rebranded Sanyo XX AA cells, while the Duracell AAA cells are rebranded 2nd-gen eneloop AAA.

[Q23] Amazon product page now says "There is a newer model of this item" and points to Panasonic BK-3MCCA8BA eneloop AA 2100 Cycle Batteries. Should I get that one instead?
[A] The 4th-gen eneloop (now marketed under Panasonic brand name) is identical to 3rd-gen except for the advertised cycle lifespan. However, the new Panasonic BQ-CC17 charger is better than the old Sanyo MQN06, because it charges each cell individually. See my review on it for details:
http://www.amazon.com/review/R1G0BC0TXRFVTT/
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I'm an early adopter of LSD (low-self-discharge) batteries, starting from the original Sanyo eneloop back in beginning of 2007. With dozens of rechargeable AA/AAA cells in use throughout the house, it would be a nightmare to keep ordinary (rapid-self-discharge) type batteries charged at all time. The only drawback of using LSD/Pre-Charged cells is that they have lower rated capacity compared to ordinary NiMH cells. Pre-charged cells are generally rated 2000-2100mAh for AA, whereas ordinary NiMH cell are typically rated 2500-2700mAh. Note that some lesser-known brands even claim up to '3000mAh', but I have found those numbers to be highly exaggerated.

I have tested a set of those newest Sanyo eneloop XX Pre-Charged Rechargeable Batteries cells, because they claim to be both pre-charged and have a much higher capacity of '2500mAh'. Date code on those cells say '10-08', which means August 2010. Here are my findings using the La Crosse BC-900 battery charger/analyzer:

- Right out of the package, the average remaining charge was 1004mAh, or just 40% of the rated capacity. The spread is very tight (990-1019mAh), which means they are indeed LSD type. Note that just like the original eneloop, those XX cells were not fully charged when they left factory,

- After just one Charge/Discharge cycle, the average capacity jumped to 2602mAh! Next cycle improved this number slightly to 2607mAH. Again the spread is very small (2570-2650mAh), indicating a good quality control.

Just for comparison, here are some of my test results for other LSD cells:
SANYO New (1500-cycle) eneloop AA: Rated 2000mAh, tested ~2100mAh (5% higher).
Rayovac Hybrid AA: Rated 2100mAh, tested ~2100mAh (same).
GP Recyko NiMH AA: Rated 2100mAh, tested ~2230mAh (6% higher).
Lenmar R2G AA: Rated 2150mAh, tested ~2030mAh (6% LOWER)
IMEDION AA: Rated 2400mAh, tested ~2450mAh (2% higher).
Yuasa Enitime PLUS AA: Rated 2500mAh, tested ~2400mAh (4% LOWER)

Some additional technical details printed on the Sanyo XX package:
- "Typ. 2500mAh, Min. 2400mAh" (The original eneloop claims "Typ. 2000mAh, Min. 1900mAh")
- "Recharge up to 500 times" (The original eneloop claims 1000 cycles, second-gen eneloop claims 1500 cycles)
- "Retains 75% of the capacity after 1 year of storage at 20 degree C" (The original eneloop claims 85%)
- "Suitable for temperature as low as -20 degree C" (The original eneloop calims -10, second-gen claims -20)

One important note: the Sanyo XX cell is _slightly_ thicker than the orginal eneloop cell. This may prevent you from using the XX in appliances with very tight battery compartments.

In summary, the new Sanyo XX cells really do offer the highest capacity among all LSD cells I have tested. Its capacity is comparable to that of ordinary 'high-capacity' NiMH cells, so you get the best of both worlds. On the down-side, it is currently priced about 2x higher than most other LSD cells. So you should only use them for mission-critical applications, where both low self-discharge and high capacity are required.

[Update on Oct 21, 2011]
Long-term self-discharge data:
- One pair of Sanyo XX cells was tested after three months of storage. The average remaining charge is 2060mAh, or 79.2% of their originally measured average capacity (2595mAh)
- Another pair was tested after five months of storage. The average remaining charge is 2040mAh, or 77.9% or their measured capacity (2620mAh). Note that if I use the rated capacity of 2500mAh as base line, then the charge retention rate is 81.6%

Sanyo claims the XX cell can retain 75% of rated capacity after one year of storage. This is consistent with my measured results so far.

[Update on May 6, 2014]
I just re-tested a pair of Sanyo XX cells after 2 years in storage. They retained an average charge of 1780mAh, which is 71% of orginal 2500mAh capacity. In contrast, eneloop cells can retain ~75% after 3 years, so the difference is not very significant.
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on October 4, 2016
I've been using Eneloop batteries since they first became available, and not a single one of over 40 cells has gone bad. None of the cells, including the very first ones I bought, have lost any capacity over the years, as measured by a LaCrosse intelligent charger.

I've purchased about a half dozen different brands of rechargeable cells over the years and none of them have lasted more than two or three years. The Eneloops do cost a bit more than other brands but they last so many times longer and continue to provide full capacity that it just doesn't make sense to buy anything else. These are much cheaper in the long run.

If you haven't used a low self-discharge type of battery before, do yourself a favor and try some of these. A non low self-charge AA nickel metal hydride battery needs to be charged every month or two as the batteries lose a little bit of charge every day. The low self-discharge Eneloop batteries maintain their full charge for a really long time. Even after a year of storage it'll still have most of it's capacity and you'll be able to use it right away without having to recharge it first. For anyone who does a lot of photography, as I do, this is a really big point.

Another plus to the Eneloop batteries is that they put out slightly more voltage than other cells. An alkaline AA cell, when new, measures about 1.5v. A typical nickel metal hydride battery is 1.2v. The Eneloops measure 1.4v when fully charged. This is means that compared to other rechargeable cells, the Eneloops will be a little brighter in a flashlight, will recharge a flash faster, and if used in a motor drive you'll get slightly faster FPS.

The slightly higher voltage makes the Eneloop batteries suitable for uses where normal rechargeable batteries aren't. A TV remote control, for instance, may not work too well at 1.2v and would require charging every month. An Eneloop powered TV remote will have almost as much voltage as alkaline cells and would probably last a year or longer before needing a recharge.
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on October 1, 2012
I'm not a tech weenie. I don't want to have to study in order to buy the best product for my needs. And when I find the "right" thing I am sure to share my opinion so other non-tech-weenies can do the same. Here is my decidedly non-technical review.

My battery needs are varied and extensive. Aside from my beloved X-Box 360 Kinect (oh yes, middle aged women also love Mass Effect series), I've also got remote controls all over the house, mobile entertainment, dog toys, holiday decorations (you know, the creepy santa that moves), portable medical equipment for my mom who lives with me, security lights in the hallways, in house remote cameras...well, a LOT of battery needs. I also have my disaster preparations because I live in a zone known for Hurricanes AND Nor'easters. So much fun.

I was spending a fortune on batteries so I thought I'd try rechargables and I got the energizer recharging kind from the regular department store. They did okay, but I clearly had to recharge them more often and they weren't nearly as good as a set of fresh tossable kind. A friend noted my drawer full of batteries one day and told me that I should give this set a try.

At only $40, it was a no brainer to give it a try and I really can't believe the difference between this system and the energizer one I bought previously. Night and day.

First off, the batteries came pre-charged and testing showed between 93 and 97% charge remaining on every single one. That's pretty good considering it sat somewhere in an Amazon warehouse before I got it. And while I do use an Xbox controller recharge station, I'd rather not wait when I do get time to play something so I usually grab another controller that isn't rechargable and I used these first in that. Turns out, my controller lasted longer with these than the one that goes with the Xbox recharger...that's pretty darn good.

I've had batteries in things for over a month now and nothing has run out (save the Xbox controller), including the safety light in the upstairs hallway that goes on and off every time a person enters the hallway...a lot of use, in other words. The case itself is super handy and eliminates the huge mess in my battery drawer.

I'm also very comfortable with these due to their ability to hold a charge. Each year I have to clean out batteries for rotation in my hurricane/storm kit and it is such a waste. With these retaining their charge...and the additional ones I bought to flesh out the kit with more batteries...I can stop that practice and know I'll have batteries ready to go. I'll update if needed. Really great buy that is highly recommended.
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on November 19, 2014
Sad to see Sanyo discontinue this charger though, its actually very well built and intelligent. Before it was discontinued, it used to be $20 out the door. Now the price hiked partially because it had to be imported

It is operated by a microcontroller, 8-bit 20MHz Atmel Tiny461 with 4 channel 10-bit ADC. It's nice to see this is a software based charger as opposed to a timer based charger. The AVR Tiny461 is wired directly to the USB port along with an SMT fuse.
I was amazed by the number of parts under the circuit board. Sanyo did not skimp on the electronics. I counted more than forty different SMT parts on the PC board. It's a 2-channel charger with a single LED indicator, 1 or 2 cells, independent charging. Charge rate is 0.18C/0.29C respectively. Charges NIMH up to about 95% capacity and I measured no voltage rise thereafter, so zero trickle charge, big plus.

Even bigger plus is a charger like this possessing six different kinds of protection feature: Individual Charging control, Peak voltage control, -dV detection, Temperature Control/ protection, Alkaline battery Detection**, Short circuited Cells detection**. (**LED light will turn off within 40 seconds). Operating it on a 5V bench supply it does not draw more than 500mA, even checked the current spikes, passed with flying colors. Its not only USB compatible, its actually USB compliant.
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on March 9, 2017
I purchased this set to get started using rechargeable and with my eneloop setup this was my first step.

These work great.

I really haven't had any issues with these batteries or the chargers.

I've even had to use the adapters in a pinch on some of my daughters toys and they've worked well.

If you get a battery holder you can use it as a way to rotate your rechargables so you're getting use across all your batteries.

I ended up purchasing a second set so I would have a spare charger. The cost difference between buying a new charger and getting the kit was negligible so I just purchased another kit.
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on December 22, 2013
I purchased the Sanyo Eneloop 2500 mah batteries for use in my Radio Transmitter for my Phantom 2 Vision Quad Copter. they came precharged out of the box just as they say. My transmitter fired right up and the operation and range was flawless and on par with my regular energizer alkaline batteries. They hold a very strong charge and last for ages.

I also used these batteries in my Xbox 360 controller and compared them to the Xbox 360 proprietary rechargeable battery and there was no comparison. These lasted much much longer. I haven't had a chance yet to test the longevity of them as far as sitting idle without use for an extended period but as time passes I'll update my review to reflect that as well. Though a friend of mine with the previous generation Sanyo's told me they had excellent results and could have them sitting for a year and hold a good charge.

To summarize. These batteries come charged out of the box, performed as well as my regular energizer batteries did in my RC remote and outperformed other batteries I tested it against. You will never have to buy another alakaline battery again. Highly recommended, 5 stars.

FYI you can use any NIMH charger to charge these. You don't need an eneloop specific charger in case anyone was wondering. I'm using an older quick charger I got at radio shack to charge my 1800mah NIMH batteries and it works just fine.
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on November 15, 2013
The package that I received is slightly opened near the bottom. The labeling on the package says "recharge up to 1800x" and "holds 70% charge after 5 years", which indicates the package is for 3rd generation eneloop. While the battery inside the package is clearly 2nd generation because the model printed on the battery is HR-3UTGA. I don't know how Amazon can ship those batteries without in its original retail package. Buyers should be aware.
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on March 7, 2016
I purchased these batteries to use in my digital camera, because I heard it would run through regular batteries very quickly. That was a mistake, as they depleted faster than regular batteries in my camera, don't hold a charge, and are now completely dead, with very little use.

These batteries don't live up to their claims. Specifically, these three, which I've found to be patently false:
**Maintain 75 percent of their charge after 3 years of storage
**Can be recharged up to 1800 times
**No memory effect - batteries can be recharged when fully, or partially drained

Over the two years I've owned these batteries, I've had nothing but problems with them. Once fully charged, if I didn't use them right away, they lost their charge completely. So the claim of maintaining 75 percent of their charge after 3 years of storage is false. The didn't maintain their charge for more than a couple of days.

In the two years of ownership, I've charged them a maximum of 25 times. Today, I went to use my camera, and it wouldn't turn on. I removed the batteries, and replaced them with batteries that had been charged 3 months ago. The camera still wouldn't turn on. So, I put 4 batteries in the charger (I use this one :La Crosse Technology BC-700 Alpha Power Battery Charger) and it indicated that all the batteries were null, meaning they were dead and could not be charged. Took them out, and put the other 4 in the charger. 2 had a small charge and could be charged. The other 2 were dead. So, the claim that they can be charged when fully discharged is false, and the claim that they can be recharged up to 1800 times is also completely false.

Considering the number of photos I was able to take using these batteries, I would have been better off not buying these, and using regular batteries instead. It would have been cheaper, and less frustrating.
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