Customer Reviews

545
3.9 out of 5 stars
Energizer Power Plus NiMH AA Rechargeable Batteries, 4-count (2300 mAh, Pre-Charged)
Size Name: 4 CountChange
Price:$12.29 + Free shipping with Amazon Prime
Your rating(Clear)Rate this item


There was a problem filtering reviews right now. Please try again later.

855 of 877 people found the following review helpful
Size Name: 4 Count
[Important Note on July 30, 2012]
My original review was about the Energizer '2500mAh' batteries back in 2006. Energizer introduced the new '2300mAh' series in 2010. I have now updated my review to reflect my opinion on the new series.

I had very bad experiences with the previous generation of Energizer 2500mAh rechargeable NiMH batteries, circa 2005. They suffer from rapid self-discharge problem (that is, can't hold a charge for more than a few days even while not in use), and have very limited lifespan (capacity deteriorated badly after just a few dozen cycles). Energizer's initial response was to change the existing series' capacity rating to '2450mAh', as if mere name change is going to solve anything. Around mid-2010, Energizer finally started to introduce a new series to address this problem. The series is named 'Recharge' and it claims to "Hold charge up to one year".

The Energizer New Recharge Batteries featured on this page is the new 'Recharge' series, with a rated capacity of 2300mAh for AA cells. I have tested a set of those new batteries, using my La Crosse BC1000 charger/analyzer. Here are my findings:

- Right out of the package, the average remaining capacity is 1684mAh, or 73% of the rate capacity.
- After the first Charge/Discharge cycle, the average capacity jumped to 2314mAh
- After three more Charge/Discharge cycles, the capacity improved slightly to 2362mAh
- After storing the batteries on the shelf for 3.5 months (108 days), the remaining charge is 88% of original capacity.

The above showed that those Energizer 2300mAh cells are indeed low-self-discharge type, similar to the better known Sanyo eneloop.

I have just one remaining doubt: Energizer seems evasive about the battery lifespan, saying only "Charge 100's of times" and "Charge up to 250 more times (than Energizer 2450mAh)". In contrast, Sanyo proudly advertises '1500 cycles' for the eneloop.

On the other hand, the Energizer cell's measured capacity is about 12% higher than that of the eneloop (rated 2000mAh, measured 2100mAh), so even if it can only last for 500 cycles, it is still worthwhile to give it a try. Just make sure that what you get is the new 2300mAh series, not the old 2500/2450mAh junk series.

==========
Old review titled "Shockingly high self-discharge rate!" follows:
==========
All rechargeable battery manufacturers love to boast about their product's current capacity (mAh). But there is a dirty little secret that they don't want you to hear: self-discharge rate. Simply put: a fully charged NiCd or NiMH cell will gradually lose its stored energy over time. Technical papers I have researched typically put the self-discharge rate at 10-20% per month for NiCd cells, and 20-30% per month for NiMH cells. This kind of self-discharge rate is usually acceptable in applications such as digital cameras.

I bought 8 of those Energizer 2500mAh rechargeable NiMH batteries over one year ago. At first, I was very happy about the large current capacity offered by those batteries. But within a few months, I started to notice that they die very quickly in my digital camera. In fact, a set of Sony 2300mAh NiMH batteries I bought one year earlier seems to last much longer when used in the same camera.

I recently did some controlled experiments (using the LaCrosse BC-900 AlphaPower Battery Charger) and found out what's wrong: The Energizer NiMH batteries have very high self-discharge rate. After fully charging all 8 cells and left them on the shelf for one week, five of them lost over 30% of their charge, and the other three lost about 20%. In comparison, the set of older Sony batteries only lost around 10% over the same one-week period.

So what this really means is: if I charge up those Energizer 2500mAh batteries and leave them in my camera for three weeks, they will become totally exhausted. I found this kind of self-discharge rate completely unacceptable, therefore I strongly advise against buying those batteries.

[Update on April 9, 2007]
I have hardly used those Energizer 2500mAh cells in the last few month. Now they have deteriorated even further. Five of them can't even hold their charges for more then a day.

Instead of the Energizer 2500mAh cells, I recommend buying the Rayovac "Hybrid" 2100mAh cells. They have very low self-discharge rate (see my review on "RAYO 4PK AA") and are cheaper than the better-known Sanyo eneloop 2000mAh cells. Kodak also sells a "Pre-Charged" NiMH cell with exactly the same spec as the Rayovac Hybrid.

The bottom line: Low-Self-Discharge NiMH cells are your best choices. There is absolutely no point in taking chances with older generation 2500-2700mAh NiMH cells now.
7171 commentsWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
116 of 124 people found the following review helpful
on October 9, 2006
Size Name: 4 Count
I've been using NIMH batteries from SANYO, NEXCELL, POWEREX and AccuPower for over 6 years. Use them for everything from high current drain digital cameras and high-end digital audio recorders to CD players, bathroom scales and flashlights.

I rely on two of the excellent MAHA MH-C401FSB smart 2-rate chargers. These charge and monitor each battery independently, not in pairs. Energizer 2500 mAH units were fine for about three months. Then I noticed that devices would be calling for new batteries with little to no use. This has never happened with other AAs NIMH, including those with less than half the advertised capacity. The MAHA charger also started reporting that some of the Energizer AAs were not taking a charge at all.

Kept finding that typically one out of four were the problem. Many of the 32 AA Energizers I bought have had problems. Repeatedly have had one battery run out of charge while others still test very strong. Felt pen dots put on discharged batteries showed it was the same batteries time and time again. Have reverted in some cases to 1600 mAH SANYO OEM batteries put in service in Feb 2001 and those provide longer and more reliable performance!

In my considerable experience with these 2500 mAH AA Energizers they have been a very big disappointment and, regardless of warranty, cannot be relied upon.
33 commentsWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
42 of 45 people found the following review helpful
Size Name: 4 Count
I bought 12 of these batteries a few weeks ago.

When tested, their real maximum capacity varies between 1100 and 2100mAh, which is very poor, and obviously well under their stated capacity.

I recommend you to get the Sony 2500mAh (which are relabeled Sanyos, probably the best rechargeable battery manufacturer), they all test >2300mAh and cost $5.99, cheaper than these mediocre Energizer units.
0CommentWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
85 of 100 people found the following review helpful
VINE VOICEon February 24, 2006
Size Name: 4 CountVerified Purchase
I used to buy excellent Maha rechargable batteries, but finally Energizer attracted my attention. Great price, great capacity. After about 20 recharges batteries are strong and do not show any signs of problems.
I use them in old, power hungry and very demanding Olympus E-10 camera. It is known to draw up to one amper of current and to declare batteries empty as far as their voltage goes slightly below 1.2 volts. Considering number of pictures I can take comparing to Maha 2100 MAh batteries, I can say Energizer is very strong performer and 2500MAh is not just a number.

Some users complained about very bad performance for Energizer.
There could be couple things to consider:
- make sure you have decent charger: many high capacity NiMh batteries can be destroyed easily with cheap (<$20) charger - overheat and overcharge are usual suspects
- some devices expect 1.5 volts, not 1.2 that all NiMh normally deliver; in general freshly charged good set of NiMh has voltage around 1.4 volts - but it goes down very fast to 1.2 v and stays there until batteries are nearly empty. Most modern cameras have "cut off" voltage set to 1.1 v

Update on Feb 7, 2007
I should mention that 4 out of my 12 Energizer batteries suddenly stopped to work. Surprisingly these are four spares I have not used much. I suspect that these batteries may develop a problem if left uncharged for prolonged period of time. For now I have bought Sanyo slow discharge Eneloop batteries (available at Amazon) as a replacement.
1515 commentsWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
156 of 188 people found the following review helpful
on March 16, 2000
Size Name: 4 CountVerified Purchase
I bought a bunch of Energizer's AA ACCU NiMH rechargeable batteries to power a halogen bicycle light and LEGO Mindstorms robots. Their performance has exceeded my expectations.
The bicycle light seems as bright as it ever was with alkaline batteries, affording good visibility during night time cycling. And stopping play---er, experimentation---with the LEGO robots for recharging has yet to be a problem.
However, I do have to issue this warning: these batteries are slightly fatter than standard AA batteries. I tried using them in a Mini Mag Light. After I got one battery in the light's barrel, I realized---too late---that I'd never get the batteries back out. I ended up destroying the Mini Mag Light in order to retrieve the batteries.
If your application is cramped for space, beware! If they do fit, expect good energy for a good long time.
22 commentsWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
14 of 14 people found the following review helpful
I had very bad experiences with the previous generation of Energizer 2500mAh rechargeable NiMH batteries, circa 2005. They suffer from rapid self-discharge problem (that is, can't hold a charge for more than a few days even while not in use), and have very limited lifespan (capacity deteriorated badly after just a few dozen cycles). Energizer's initial response was to change the existing series' capacity rating to '2450mAh', as if mere name change is going to solve anything. Around mid-2010, Energizer finally started to introduce a new series to address this problem. The series is named 'Recharge' and it claims to "Hold charge up to one year".

The product featured on this page (Rechargeable Batteries, NiMH, AA, 4/PK) is the new Energizer 'Recharge' series, with a rated capacity of 2300mAh for AA cells. I have tested a set of those new batteries, using my La Crosse BC1000 charger/analyzer. Here are my findings:

- Right out of the package, the average remaining capacity is 1684mAh, or 73% of the rate capacity.
- After the first Charge/Discharge cycle, the average capacity jumped to 2314mAh
- After three more Charge/Discharge cycles, the capacity improved slightly to 2362mAh
- After storing the batteries on the shelf for 3.5 months (108 days), the remaining charge is 88% of original capacity.

The above showed that those Energizer 2300mAh cells are indeed low-self-discharge type, similar to the better known Sanyo eneloop.

I have just one remaining doubt: Energizer seems evasive about the battery lifespan, saying only "Charge 100's of times" and "Charge up to 250 more times (than Energizer 2450mAh)". In contrast, Sanyo proudly advertises '1500 cycles' for the eneloop.

On the other hand, the Energizer cell's measured capacity is about 12% higher than that of the eneloop (rated 2000mAh, measured 2100mAh), so even if it can only last for 500 cycles, it is still worthwhile to give it a try. Just make sure that what you get is the new 2300mAh series, not the old 2500/2450mAh junk series.
22 commentsWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
19 of 20 people found the following review helpful
on December 10, 2006
Size Name: 4 Count
Be careful. If you plan to charge and use these immediately, they're OK. If you plan to leave them on the shelf for a couple of weeks...they will be dead. Problem gets worse after about 6 months. High capacity is useless. My Rayovac's (1800 mAH) are much more useful.
0CommentWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
20 of 22 people found the following review helpful
on August 3, 2009
Size Name: 4 Count
NiMH rechargeable batteries from two generations ago had capacities around 2000 mAh and they were pretty decent. There was chemistry change around the 2005 timeframe that allowed for higher capacities such as these Energizer 2450 mAh batteries, but that came with a major tradeoff. Yes you can get the higher capacity, but they would discharge at a much much higher rate just sitting there. Charge them and in a few weeks they'd be dead again. The previous generation might have lasted 2 months before going completely dead.

These Energizers are simply the worse of the worst for self-discharging. They weren't so great brand new, and after being in service for a bit mine are down to where they will self-discharge in about a day. No joke. They're useful if and only if you're going to know 8 hours ahead of time when you'll be using them, quickly pop them out and shove them into your device, and then use that device in such a way that they'll be drained within a couple hours.

Instead, there's is a new generation of NiMH batteries called Low Self-Discharge. They have sneaky packaging like Duracell Precharged. They also show a lower NiMH rating on the package, so you might look at them and laugh as I did the first time I saw one in the store. "Precharged? Who cares? Look, it has 80% of the capacity of these Energizers..." Well, don't believe the lack of hype. They've managed to solve the number one issue with rechargeable batteries, yet don't communicate fact that effectively enough on the packaging.

Instead, these new LSD batteries hold the charge almost as well as alkaline batteries. This unstated fact entirely changes how you can use rechargeables. It used to be that you would change the batteries immediately before using them. Now, you simply use them in your device. When you pull them, charge them back up and then toss them in the drawer to be used again next time. If you have kids with toys, then you know how how important it is to have batteries at the ready, and the new LSD batteries actually fit the bill. If you use these in a digital camera or flash, charge them and leave them in the camera. They'll be ready to go when you're ready to use the device.

In short order... avoid these Energizers and buy one of the following instead....

Duracell Precharged
Kodak Precharged
Rayovac Hybrid
Sanyo Eneloop

Rigorous testing by verified nerds shows that they each perform within a few percentage points of each other, so just get whatever is on sale. The Kodaks and especially Duracells can be found in local stores.
0CommentWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
11 of 11 people found the following review helpful
This product is advertised as the NEW Energizer Rechargeable NiMH AA Batteries. But once you received it, you may be shocked to find out that: the rated capacity of those NEW batteries is just '2300mAh', lower than the previous generation of '2500mAh' Energizer NiMH cells. So are you really getting a new and improved product, or just some old inventory from many years ago?

The fact is, Energizer has discontinued the '2500mAh' series of rechargeable AA NiMH cells, presumably due to massive complaints about rapid-self-discharge problem. All new Energizer rechargeable AA cells on the market now are rated '2300mAh'.

I have tested four of those new cells, using the Discharge/Refresh function of my La Crosse BC-900 charger/analyzer. Here are my findings:
- Fresh out of the package, those cells hold an average of 330mAh, or just 14% of the full capacity.
- After fully charging them for the first time, they hold an average of 1040mAh.
- After two more discharge/charge cycles, the average capacity improved to 2340mAh

Based on the above observations, I can conclude that those 'New' Energizer cells are just ordinary NiMH cells with lower capacity. They are not the LSD (low-self-discharge) type pioneered by SANYO eneloop. This is very disappointing, because other name-brand battery makers have already introduced LSD products similar to eneloop, such as the Rayovac Hybrid and Duracell Pre Charged. In contrast, the Energizer Bunny simply 'rolled back' its battery technology to circa 2004.

The only positive thing I can say about those 2300mAh Energizer cells is: they _probably_ don't self-discharge as badly as previous generation of 2500mAh cells.

In summary, those so-called 'New' Energizer NiMH cells have capacity just slightly higher than LSD NiMH cells (2000-2100mAh), yet do not offer the advantage of lower self discharge rate. As of this writing, this product is priced at nearly 2x higher than LSD cells. So it is just a bad deal.
0CommentWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse
51 of 65 people found the following review helpful
on September 25, 2000
Size Name: 4 Count
These AA rechargeable batteries work well and will save you money over the long term - however, if you click on the picture of the product, you'll notice that these batteries are rated at 1200 mAh. The Kodak rechargeable batteries (also available on this site) are rated at 1450 mAh and are THE SAME PRICE!!! If you aren't into the technical explanation of what the numbers mean, I'll help you; you get more juice for your buck with the Kodak product.
0CommentWas this review helpful to you?YesNoSending feedback...
Thank you for your feedback.
Sorry, we failed to record your vote. Please try again
Report abuse

Questions? Get fast answers from reviewers

Please make sure that you've entered a valid question. You can edit your question or post anyway.
Please enter a question.
See all 25 answered questions


Send us feedback

How can we make Amazon Customer Reviews better for you?
Let us know here.

Your Recently Viewed Items and Featured Recommendations 
 

After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in.