Customer Reviews

Energizer NH15BP-4 Rechargeable AA Battery 4 Pack

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3 star:		(9)
2 star:		(26)
1 star:		(66)

 

 

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.

[Update on Oct 20, 2010]
The product image of Energizer Rechargeable AA has changed. It no longer advertises '2500mAh'. I went to my local W*mart to check out the actual batteries. All Energizer rechargable AA cells are now 2300mAh. Evidentially, Energizer has 'rollled back' battery technology to 2004. This is actually a good move because the lower capacity cells do not suffer from hideous self-discharge rate. Contrary to popular belief, a 2300mAh cell is not any less capable in delivering high power than a 2500mAh cell. Just that the run time will be about 8% shorter.

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.

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.

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.

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.

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.

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.

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.

I bought these batteries and they were a total disaster. They would run out very quickly and need frequent recharging. When I left the batteries (fully charged) alone for a few days I would come back to find them completely drained. I ordered the "GE/Sanyo eneloop 4 Pack AA NiMH" on Amazon, and they were great. I don't have to charge them too often, and I can leave them for weeks and use them again for another round of photos. I highly recommend you steer clear of the Energizer, and go with the GE/Sanyo which is about the same price. Unlike these Energizer batteries, the GE/Sanyo keep going and going...

In theory, these batteries will save you at least $1,000. They cost about $30 with the charger and you can charge them up to 1000 times. If a set of regular batteries costs $4, that savings equals $3,000 over the lifetime of the product. Well, i can't imagine using regular batteries ever again.

If i can only charge these 500 times, that's good enough for me.

I bought these batteries because i use my CD walkman regularly - every day to and from work. That is the only piece of equipment i own that i use batteries for really. These particular rechargables last longer than Rayovac rechargables, and definitely last longer than Alkaline consumables, making the savings to you even higher.

If you own ANYthing that takes batteries that you change 10 times a year, BUY THESE!!! You will save money, frustration, the environment and time.

I bought the 4 pack, my walkman uses 2, so i just switch them out once every 10 days, at this rate i can't imagine buying a new set for 7 years. Hmmm...that seems strange but what seems stranger is the thought of buying non-chargables. So even people with minimum usage for batteries will save money. If you have more than 1 person in your house, i can't see going without, you would be throwing you money down the drain.

Their are several styles of chargers for the ACCu series. A large one for various styles of batteries, a compact for AA & AAA batteries, another Compact for AA NIMH or NICA. I have the last one, it is small and cute and people always ask me about it, then i just start raving.

The only problem i see is that it does take over 10 hours at first and for a full charge, but that is no big deal. Buy an extra set of two if you frequenly need them right away.

HIGHLY RECOMMENDED.