eneloop vs Powerex?

DirtyRat

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I've noticed there isn't even really a debate around here, there seems to be no questioning the Sanyo eneloop AA batteries. My question is, why? I understand everybody believes they're extremely reliable, but why doesn't Maha's Powerex 2700 AA battery which has 35% more juice than the eneloop 2000, get any attention around here? I'm not starting a arguement because I've never used an eneloop so I don't know their lasting power, but it just seems to figure that a battery with a larger capacity (an in my experience, a very reliable battery, just don't drop 'em, killed two from 6 ft. drops) would make more sense in flashlights.

I started on Powerex's off a very battery educated person's opinion about 12ish years ago. This kid was a genius and he didn't hesitate to suggest to me Maha Powerex for my digital camera, I've bought dozens and haven't been disappointed.


Anyhow, again, not looking to start a GM vs Ford argument, or Honda vs Toyota if imports fit your fancy, but I'm just wondering why Powerex is rarely mentioned in these parts.


P.S. My 1st posts involved needing a flashlight recommendation, and I was lead toward the SC51, which I've been using for about a week now...LOVE IT. Will post much thanks later.
 

T-roc87

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Its becuase the sanyo eneloop 2000 mah are a low self discharge battery which is great for those of us that dont use our lights on a nightly basis. They are able to hold like a 85% charge after a year of sitting. That would be why they are so well liked.
 
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derfyled

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Regular NIMH like Powerex loose about 1% of their capacity per day when stored.
 

DM51

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The_bad_Frag

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You can buy Eneloop XX if you want more mAh. They have 2500 mAh and the same low self discharge rate as normal eneloops.
 

tbenedict

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I had a bunch of Powerex 2500's and 2700's due to the reviews from the camera sites. All of mine faded out to where they are only good in the Gerber IU's. I have not had one Eneloop go bad in the last several years..
 

RCM

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The highest capacity AA NiMH cells seem to die rather quickly, 2 of my Duracell 2650s (Sanyo 2700 mAh) now have incredibly high internal resistance, and will NOT charge anymore, they have been retired to my recycle bucket along with a REALLY crappy Chinese made 350 mAh NiCD that had it's polarity reversed AND leaked! I use duraloops a lot now...
 

samgab

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Incidentally, eneloops are Low SELF Discharge (as opposed to low discharge, which sounds like you can only discharge them at low rates).
 

RCM

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Alkalines should only be discharged at low rates, otherwise you risk reverse polarity! NiMH is better for higher current, but you should be sure they are matched, otherwise you risk polarity reversal with them as well, which causes damage to them! If it was me, I would go with the eneloop XX for lights that I use all the time, and regular eneloops for lights that don't get used that often.
Just my 2 cents.
 

pinetree89

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I bought a grundle of Powerex cells a number of years ago. They didn't last long, most would self discharge in a number of days. I've since gotten rid of all of them. They're pretty bottom of the barrel cells IMO. Eneloops are worth the price, they'll be there with a charge when you need them. I've also had good luck with Rayovac Platinums, but the edge goes to the Eneloops.
 

Battery Guy

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I've noticed there isn't even really a debate around here, there seems to be no questioning the Sanyo eneloop AA batteries.

First, you are comparing apples and oranges. The Powerex 2700 cells are not LSD (low self discharge) NiMH cells. I consider these to be almost a different cell chemistry as their usage and maintenance attributes are quite different.

Second, please take a look at the extensive testing that has been done comparing various AA NiMH cells to Eneloops found in the AA NiMH Performance Test Thread. You will see that a lot of work has been done to compare various cells to Eneloops.

I have not tested the Powerex 2700 AA, but I have tested the Powerex Imedion 2400 AA, keeping in mind that the 2700 is not LSD and the 2400 is LSD. The Imedion 2400 cell does have higher capacity than the 2000 mAh Eneloop, but it has a much higher internal resistance.

For raw performance in an LSD NiMH AA, you simply cannot beat the conventional Eneloop and the Eneloop XX (aka Eneloop Pro). The new Elite 2000 cells beat the Eneloop on power capability, but they do not have the LSD properties of an Eneloop.

Paraphrasing Mr. Happy from a post long ago: "There are two types of LSD NiMH cells, Eneloops and non-Eneloops." My testing seems to confirm this. Sanyo simply has the edge when it comes to this type of cell. Specifically, they have low internal resistance, fantastic capacity retention, excellent calendar life and outstanding cycle life. I don't think that any other LSD NiMH cell is equivalent on any of these performance metrics.

That being said, Eneloops and Eneloop XX cells are pricey, and you can find other NiMH cells that give you more from an initial $/Ah metric. However, no NiMH cell has the track record of the Eneloop.

Cheers,
BG
 

bbb74

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Its becuase the sanyo eneloop 2000 mah are a low self discharge battery which is great for those of us that dont use our lights on a nightly basis. They are able to hold like a 85% charge after 3 years of sitting. That would be why they are so well liked.

I do think that if you have cells that sit around doing nothing for 3 years, given the cost, lithiums would be a better choice than eneloops.

First, you are comparing apples and oranges. The Powerex 2700 cells are not LSD (low self discharge) NiMH cells. I consider these to be almost a different cell chemistry as their usage and maintenance attributes are quite different.

I have done some comparisons which include power 2700, imedion 2400, eneloops and vapex instant 2400's here: http://www.candlepowerforums.com/vb/showthread.php?317990-AA-NiMh-Shootout!!

From this testing (and from my experience) the powerex 2700's are close to LSD in self discharge, but they lose capacity much faster than the others with the number of cycles of use. Unless capacity was the *only* thing that concerned you, you'd be better off looking at the imedions or vapex (I'm only listing brands I tested). For the lowest capacity but probably most amount of toughness, go the eneloops.

I've got imedion 2400's that have been smashed around on the front of my bicycle for over a year now. After ~90 cycles they've lost about 2% of their original capacity which is excellent in my book. I don't have eneloops getting the same treatment to report on. The powerex getting similar treatment (but fewer cycles!) are down well over 10%.
 

Wrend

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One of the distinguishing characteristics I've added to my list of things to check to determine the quality of a cell is its expected cumulative lifetime capacity.

In this, standard "1500" cycle Eneloops even beat the XX Eneloops by 2.4x, which seems the better value to me than the 1.25x capacity per charge.
 

snakyjake

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I've presumed that if I plan to deplete my battery within a month, I'd be better off with high capacity non-LSD. The PowerEx 2700 has 35% more capacity than LSD 2000. With a decay rate of 1% per day, it should take more than 35 days to break even with a 2000 LSD. But now some are mentioning cycles, so I don't know anymore.
 

Mr Happy

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The 2700 cells are good when they are new, but they don't stay new and you may expect some cells in a group or pack to get out of balance, to develop high self-discharge, or to go high resistance after a possibly short time of ownership. Additionally they have a higher internal resistance so will develop a lower voltage under load than some other cells.

You are making a trade-off between cost and ultimate capacity. If you are prepared to buy new cells and replace them often in the pursuit of maximum capacity then the 2700's may be for you. If you are looking for economy, assurance and general lack of fuss, then eneloops would be the better choice.
 

Groundhog

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I use both the Powerex 2700's and the Eneloops.

I use the Powerex in my bike light and my EDC light because I generally use a 4pk within a week of charging them and I think there is a little longer life in that battery. In my remotes it is definitely Eneloops. They don't lose their charge after a few months so I am changing batteries a lot less often. For a digital camera that you are using frequently the Powerex is a fine choice if you have a freshly charged battery. If it might sit for a couple months before use I'd go with an Eneloop.

With LSD batteries up to 2500 mAh the Powerex 2700's are almost outdated technology. A dozen years ago when your friend recommended the Powerex he was giving you a great tip on a battery. There's a good chance he is using Eneloops today in many devices.

I'd give the regular Eneloops a try next time you buy. Keeping 85% of their charge after 3 years in a drawer is kinda handy. They may not become your preferred digital camera battery but I'm sure you will be pleased with their performance in remotes and such.
 

DirtyRat

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Thanks for all the responses. Great read, very informative, as well as the links to other topics about this. I didn't realize there was this forum about batteries. I normally hop straight to the LED forum. For my use, I burn through a AA a week, normally 4 days it seems. I use my SC51 very often at work, so to me it seems to make sense to use the higher capacity jobs, as self discharge over an extended period is not a concern for me.

Incidentally I am using the 2400 LSD Imidion in my Zebralight, and somebody commented that the Imidion is higher internal resistance than enellops, I wonder if this is why I notice little difference between this highest high setting, and the lowest. I think the lowest is around 100 lumen, and the highest is 200, well it's definitely not twice as bright. I'd wager 50% brighter, but not twice as bright. Based on the thoughts I put some eneloops on my Christmas list! Sadly the XX ones don't seem to fit the bill price wise, simply too expensive.
 

Mr Happy

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I think the lowest is around 100 lumen, and the highest is 200, well it's definitely not twice as bright. I'd wager 50% brighter, but not twice as bright.
That seems about normal. 200 lumens doesn't look twice as bright as 100 lumens because our eyes don't perceive brightness in that way. The only way to really tell is to use a light meter.
 
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