Customer Reviews

Powerex AA 2700mAh NiMH Rechargeable Batteries w/holder- 4 Batteries Per Pack

5 star:		(56)
4 star:		(8)
3 star:		(4)
2 star:		(7)
1 star:		(15)

 

 

I've been using various Powerex batteries to run my power-hogging Minolta Dimage 7Hi since 2002, and in that time have occasionally tried some other rechargables... not a single other rechargeable has come close to delivering the output of the Powerex's.

My most recent purchase was two 4-battery sets of the 2700 mAH versions, and they have been just superb.
Not many people know that it is recommended to recharge your batteries every month to keep up their capacity and if this is not done the performance can degrade.

Even excellent rechargeables wear out, but you can expect a couple of years of great results from these, highly recommended for high-demand digital cameras.

In this time, my original Maha MH-C204F charger has provided faithful service and is still working fine. If I were getting into the rechargable game now I'd go for the MH-C9000 WizardOne Charger, because it treats each cell individually instead of in pairs.

Glad to see Amazon is finally offering Powerex.

I am a wedding and portrait photographer, so I am always on the lookout for long-lasting, quick recycling rechargeable batteries. I have tried Lenmar, Wewin, Calumet and Energizer batteries for my strobes and the Powerex have outperformed them all. In particular, when charged in a Maha charger, these puppies will last! You can't go wrong with Powerex.

I own the 2200 and 2300 series batteries and love love LOVE them! They are inexpensive and last seemingly forever.

Last year I helped document a project my classroom was doing for Very Special Arts. I charged up batteries and brought a spare set for just in case. I took over 1000 pictures and filled up my memory card before I ran out of juice in the first set of batteries. The other camera used to document this project ended up being the secondary camera because they kept having to stop to recharge the battery.

Because of how reliable these batteries have been I have started basing electronic purchases on if they take AA or AAA batteries or not. I have saved a lot of money because I don't have to buy spare stock batteries. I have 18 Powerex batteries that I use over and over for the past 2 years and haven't had any problems with them.

The charger is simple to work and holds the batteries to charge better than other rechargers I have owned. There is a feature to discharge the batteries should you need to do so.

I can't begin to imagine how much I would have spent on regular batteries had I not gotten these.

I run a production business and use a lot of mobile power. I put 24 of these in service a year ago and none of them are holding a charge >1950 and two of them have shutdown completely. They are properly cycled and cared for, charged for use only once a week, but they were a huge disappointment.

I'm going to buy 40 Sanyo 2700 NIMH and see how they hold up.

so there's no doubt, I use MAHA C9000 for diagnostics, and a maha C401 and MAHA MH-C808M AA - AAA- C- D BATTERY CHARGER DELUXE 8 CELL PROFESSIONAL BATTERY CHARGER-FULL LCD DISPLAY for charging. The batteries are not left in after charge, and not exposed to temperature extremes.

I am an end user with no affiliation to any battery company.

Trust me, there is NOTHING better than these 2700 mah batteries for high discharge rate devices like camera flashes. As a wedding photographer, four of these last me through an entire wedding shoot, including indoor reception. That is about 800 pictures with fill flash and flash as the primary! I have read forums for hours and hours and this is the conclusion of others as well.

As a pro, label all your batteries and use them together - dont mix and match old with new. After a year of use buy new ones for your flashes and use the old ones for whatever consumer devices need a great rechargeable.

A MUST: Buy the BC-900 charger and do a discharge/charge cycle (at 1000mah, always try to set charge amps at half capacity of battery) to test your batteries on purchase and regularly thereafter. The last batch of these only tested at 1200 mah (which was very strange) so I returned them directly.

NOTE: these have a high self discharge rate so charge them the night before and let them trickle charge overnight before use the next day. If you need a battery to sit for a month in between uses (like a digital camera), then get SANYO eneloop 4 Pack AA NiMH Pre-Charged Rechargeable Batteries and don't look back.

NOTE: these are HEAVY and a tiny bit wider than your average AA battery. In Vivitar 285 flashes they are stuffed tight into the battery compartment and are difficult to remove.

ENJOY!

i have two sets of four and the powerex charger. i charged up four and put them in my camera when i got it in january 06. last week those original batteries finally ran out of juice. i use my camera quite often and was amazed how long these batteries lasted. simply the best choice for rechargeable batteries on the market.

After charging these batteries using the Break-In/Forming charge on my Maha/PowerEx C-9000 charger, the actual AH ranged from a low of 2580mAH to a high of 2623mAH, with an average of 2599mAH. Although advertised as 2700mAH batteries, the manufacturer's published minimum guaranteed capacity is 2500mAH, of which they all exceeded.

After reading other reviews of this battery, I have not found the poor performance many others have experienced.

One conclusion may be that the batteries are being improperly charged. Improperly charging a battery is a sure way to damage it. Typically a battery can be charged two ways; either a trickle charge (with the typical overnight or 16 hour chargers), or fast charge (1, 2, 4, or 8 hour chargers).

When the battery approaches overcharge, a fast charger MUST reduce the charge rate. If the rapid charge rate is allowed to remain applied when the battery is fully charged, the battery risks damage, a blown overpressure seal, leaking electrolyte and so on. NiMH cells in particular are very sensitive to high overcharge current and can be easily damaged.

When a battery is trickle charged, the charge rate is not sufficiently high enough to damage the battery when it goes into overcharge. While charging for 16 hours is not as convenient, it is the safest method of charging, and will actually charge the battery to a higher capacity than a fast charger (unless the fast charger is a combination fast/trickle charger).

Since fast chargers must reduce their charge rate prior to going into overcharge, a method of sensing the battery's voltage, temperature, or a combination of the two must be employed so that the charger can detect when the battery is close to overcharge. For most fast chargers, there is a margin of of safety built into the charge profile so that the fast charge is removed well in advance of overcharge. This will result in the battery having less than 100% charge.

Some of the better fast chargers do switch to trickle charge at the completion of the fast charge to complete the charge. This still takes time, and often requires several hours of trickle charge to put a 100% charge into the battery.

Cheap fast chargers may not even sense overcharge, but simply provide a timed charge. With these chargers, unless the battery is fully discharged, the risk of high-current overcharge is significant.

The mechanism used in a fast charger to determine when a battery is at the threshold of overcharge is somewhat dependent on the manufacturer's battery design variances, battery capacity, and other factors.

Due to these factors, and efforts to keep charger costs low, a specific manufacturer's Fast charger may not be sophisticated enough to employ the proper circuitry to properly detect the overcharge point of another manufacturer's battery. Therefore, charging different brands of batteries on another manufacturer's FAST charger, while assumed as safe by many, may NOT safe in my opinion, and can cause battery damage.

One exception are the high-end Charger/Analyzers made by Maha/PowerEx and LaCrosse. These chargers use sophisticated overcharge detection circuitry to monitor voltage, changes in voltage, and temperature. Even then, if you incorrectly setup one of these chargers, you may still damage a battery.

Most battery manufacturers state that you will void the battery warranty by charging the battery improperly, which includes the use of other brand chargers. There is more to this than liability, there is a significant risk of battery damage.

However, it is generally accepted that overnight/16 hour/trickle chargers are safe for charging any brand battery, and notwithstanding any manufacturer disclaimer, may be safely mixed brand-wise. While there are always exceptions to even this convention, the charge rates are (hopefully) generally low enough that overcharging the battery will not damage it.

I am not sure why many folks are having problems with batteries, but perhaps it's due to improperly fast charging them.

To restate, I would never recommend FAST charging a battery on another manufacturer's FAST charger, unless it was specifically designed for that purpose (most of which are not).

Top rated batteries and top manufacturer. They run at least 2xs LONGER than lower capacity (2000- 2200) mAH batts. I also compare their better performance & Run time in my previous review of the 4-pack eneloops. These quality 2700 mAh batts outperformed those 2000 mAH batteries by an Addtl ~ 48+ hrs, in [continuous] RUN time & illumination in my led string lights...

One review, elsewhere, reported these Powerex batts to be shy of 200 mAh. The (minimum) on the label reads 2500 mAh, perhaps that person tested it when not [fully] charged. NO two cells/ batts are exactly the same, but so far I've only known one @ the lowest to be down by ~60 mAh. Yet, they average above 2700 mAh.
-These batteries have been ranked TOP pick in a number consumer tests!- search ur self...

Sanyo's 2700 mAh (AA)batteries are very good too. These two brands are the true contenders(right now). I would pick 1 over the other, based on sale price or latest technology release. If I see a battery comparison on Sanyo Vs other brands w/out incl. Maha /powerex - I would question some bias present.

It's obvious that Maha/ Powerex is not as well known here, maybe b/c they're not often sold in typical retail chains. But they're no stranger in the professional shops, Photo magazines & online! - I'm saving 0.5 stars for when Maha releases an (AA) with even higher mAh!- not certain when, but fingers crossed...
----shop around 4 these- sale prices vary...

BACKGROUND:

I wanted a NiMH AA/AAA charging system that would remove the "mystery-of-the-charge" and provide more confidence in the rechargeable batteries I purchase. So, I did a little research like everyone does (or should do) before buying an item that's intended to last for years (find "The Best (aa/aaa)Charger Guide by John Dziadecki on Amazon - excellent read). I decided to buy two 4-packs of Powerex AA 2700's and two of Powerex AAA 950's to supplement some Duracell 2650's, Kodak 2550's, Energizer 2500's and an assortment of generic 2300's. I also bought two chargers: the MH-C9000 and the MH-C800S.

For years I've used an assortment of chargers with idiot lights. I had no idea HOW MUCH of a charge those batteries were getting or whether they really held the advertised capacity. But, it was very clear (and frustrating), that some of these batteries and/or chargers were very limited (junk?). I'm not sure how many times I installed newly charged NiMH batteries into a digital camera only to have the low battery icon show up after a couple shots: "Hmmmm...how many of these batteries are duds?" And, generic battery testers really don't tell you much, i.e., how 'good' is "Good"; How 'low' is "Low"? .....So, it took me a while to get fed up.

MH-C9000 Charger:

This thing definitely took most of the guess-work out of my rechargeable AA/AAA energy supply. I was able to get rid of six old NiMH AA's in the first week and "rescue" seven others with this charger. The directions with the charger are a little sketchy but, if you know the advertised capacity of your battery and its age, you'll be able to figure out how to best charge it and how many mAh's are available to you afterwards. You'll also be able to determine if the battery is shot. This isn't something you get to do with idiot-light chargers (which work just fine for lots of people). I remain very impressed with this charger.

MH-C800S Charger:

I bought the MH-C800S to supplement the -C9000 because of its 8-battery capacity. This charger does not provide battery capacity values at the completion of a charge cycle. It does however, have a 16-hour 'conditioning mode' designed to re-juvinate and cycle (discharge and recharge) batteries: it works very well. If you don't care about actually 'seeing' the specific capacity of your batteries, the MH-C800S is a good choice at the right price. It too will tell you if your battery is shot. This charger is all that most people will need or want for AA and AAA re-chargeables.

CAPACITIES:

I have not used Powerex re-chargable batteries long enough to comment on their discharge rate. But, thus far I haven't seen a difference between my older 2300 and 2700 mAh re-chargeables and the Powerex batteries. It's also too early to determine if the Powerex batteries will last through 1000's of charges.

The Powerex AAA batteries have an advertised capacity of 950mAh. They charged out between 956-967 in the MH-C9000's "Break-In" mode. Allowing for heat attenuation, full capacity is about 920. I'll know more when I recharge them.

The Powerex AA batteries have an advertised capacity of 2700mAh. They charged out between 2556-2650 in the MH-C9000's "Break-In" mode. Allowing for heat attenuation, full capacity might be about 2300. I'll know more when I recharge them.

Some of my older batteries charged out at significantly higher rates than advertised after putting them through the MH-C9000's "Refresh and Analyze" mode: these older batteries are holding charges longer and they discharge more consistently. I can tell that those instances of partially-charged batteries screwing up the camera's current requirement will be fewer. At least now, I'll be able to sort out the weak, lame and starving in the herd.

SUMMARY:

Of course, there are other ways to do what I did. The Powerex battery purchase was based on the charger purchase: I figured it best to stay with a certain brand and keep the system homogenous. Not necessary at all. The price was right for the batteries and they came with convenient storage cases. In time, if Powerex batteries don't perform well, I'll probably start replacing all my batteries with an assortment of Sanyo Eneloops. I'm in the process of learning what a good rechargeable AA/AAA battery really is.

There are several other chargers that perform similar to the MH-C9000 and -C800S: LaCrosse, Sony, and/or Sanyo. Reviews for the Powerex MH- products appealed to my technical comfort level and budget. Good stuff!

These are without doubt the best AA batteries I have ever owned. I used these during wedding for my flash unit which usually really sucks batteries dry. I was going through two sets of Duracell batteries for one wedding. These PowerEX batteries lasted the entire wedding and beyond!! After using these batteries to shoot the wedding I discharged the flash manually using full power an Additional 72 times before they worn down!!