# Eneloop - Performance Details for Experts



## Bones (Jan 13, 2009)

The Sanyo Europe website has recently evolved into a trove of information on the Eneloop including plenty of graphs and diagrams.

Here are hyperlinks to a some of the most relevant pages:

Cover - an Overview

Capacity - Nominal, Stored and Under Discharge

Self-Discharge - Capacity, Voltage and Higher Temperatures

Discharge Currents - Performance at Higher Currents

Low Temperature - Discharge at Low Temperatures

Voltage - Operating Voltage and DSC Settings

Cycle Life - Cycle Characteristics and Comparison

Technology - Construction and Self-Discharge Reduction

Q & A - Eneloop Questions and Answers

A very detailed .pdf document entitled 'Development of Low Self-Discharge Nickel Metal Hydride Battery' from the Sanyo Technical Marketing Department:

http://www.eneloop.info ... editors.article.pdf

But one of the available graphs; this one compares the cycle life of 3 regular NiMH cells and 3 Eneloops which were basically flogged to death, albeit not to anywhere near the degree exercised by SilverFox:







I can't help but contrast the exceptional amount of information that Sanyo has disclosed about the Eneloop with the dearth of information disclosed by virtually every other brand of low self-discharge cell.

This, combined with the thus far exemplary performance, quality and consistency of the Eneloop, does seem to reflect a company that's actually deserving our business.

Here's hoping the merger with Panasonic doesn't screw this up.


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## Cydonia (Jan 13, 2009)

This is quite amazing really, when you think about it, this overabundance of information in contrast to the... paucity offered by the "other" manufacturers.

But being the rotten cynic that I am… I can’t help but suspect we have seen the high water mark of quality LSD NiMh cells embodied in the Sanyo Eneloop. A retrenchment into dubious and sporadic quality equivalents is all but assured in the future according to my pessimists outlook :ironic:
In other words this is all too good to last.


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## Black Rose (Jan 13, 2009)

Wow, what an amazing amount of information.

Yeah, lets hope that Panasonic sees fit to keep the Eneloop alive.


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## 45/70 (Jan 13, 2009)

Interesting links, Bones, thanks. I didn't look over everything yet, but some of the graphs are surprisingly similar to Tom's (SilverFox).  Thanks to him, we've been aware of a lot of this, due to his efforts. That's not to exclude a lot of other members findings, as well.

Re: the graphs again, I always am amazed at how well the eneloop's hold up their voltage under load, as opposed to other NiMH's, including other LSDs. That, to me, is one of the best features of the eneloops. I don't think a lot of people notice, or appreciate, how this affects a battery's performance. In this respect, the eneloop's kill even Sanyo's own NiMH's.

Dave


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## coppertrail (Jan 13, 2009)

Yes, thank you ,great info. Love some of the grammer "they can be used in mouses . . ."


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## lctorana (Jan 13, 2009)

Quote from this website:
Even if you discharge eneloop with 4.000 *mAh*...

Amusing. Even the real battery professionals make this boo boo.

Fabulous website. Thanks for the links - we can fully design on paper to our heart's content now!


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## UnknownVT (Jan 13, 2009)

Bones said:


> The Sanyo Europe website has recently evolved into a trove of information on the Eneloop including plenty of graphs and diagrams.
> Voltage - Operating Voltage and DSC Settings


 
WoW! thank you very much for the heads up on this information.

There are some pretty silly typos "accellerated"(sic) in the graph you posted, and in the link above for the Voltage "_The voltage makes the *differene*_"(sic)

Anyway all that is trivial when compared to the wealth of information.

The information at the Voltage link was very relevant for what I had been discussing over at the Pentax dSLR forum on eneloop voltage maintenance - K200D Battery Meter Problem

I'll paste what I said below -

..... by careful measurement it was determined that the cutoff voltage threshold in the Pentax K200D dSLR was about 1.15V with a max current demand of ~1.5Amps

conventional high capacity NiMH batteries will outperform eneloops if they are recently charged (ie: not stored for too long before actual usage).

Here are the comparisons - again using the discharge curves by SilverFox taken from NiMh Battery Shoot Out 

I drew the same horizontal 1.15V threshold cutoff red-line 
then noted the points at which the 2Amp and 1Amp discharge curves crossed that red-line and found the mid-point between those (this should approximate where a 1.5Amp curve would cross the 1.15V red-line - not exactly right but probably close enough for this look-see comparison) 
and dropped a vertical red-line to the horizontal axis to note the actual Amp-Hours delivered.

eneloop





Energizer 2500 mAh





Duracell 2650 mAh





those readings were approx 

Sanyo 2700mAh = 2.265 A-h
Duracell 2650mAh = 1.881 A-h
eneloop = 1.66 A-h
Energizer 2500mAh = 1.61 A-h
GP ReCyko = 1.54 A-h
RoV Hybrid = 1.43 A-h

So the high capacity Duracell 2650 mAh (and Sanyo 2700mAh) do beat the eneloop when they are recently charged and in good condition. 
But the Energizer 2500mAh is lower than the eneloop even when recently charged.

However when aged high capacity NiMH are notorious for developing high rates of self-discharge and can lose their capacity (eg: Ref1 Ref2 Ref3) - so that the LSD (Low Self-Discharge) batteries eventually will cross-over and perform better in longer storage before use situations.

To be fair when one is going to use the K100D/K200D a lot - then charging up a set of those better performing high capacity NiMH on the day or night before probably will show better performance from eneloops under the same conditions.

But if the batteries are stored or partially used for anything over a month or 2, then the eneloops are probably going to do better at that point.

Also see:

summary post #*57* of eneloop vs. Kodak Pre-Charged Voltage Maintenance


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## Nubo (Jan 14, 2009)

lctorana said:


> Quote from this website:
> Even if you discharge eneloop with 4.000 *mAh*...
> 
> Amusing. Even the real battery professionals make this boo boo.



Some countries use a period for grouping thousands.

http://en.wikipedia.org/wiki/Decimal_separator


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## saabluster (Jan 14, 2009)

Nubo said:


> Some countries use a period for grouping thousands.
> 
> http://en.wikipedia.org/wiki/Decimal_separator


That was not the issue. He was referring to the reference to *"mAh*".


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## was.lost.but.now.found (Jan 14, 2009)

I'd be very curious to know what battery was used as their comparison as the standard (non LSD) NiMH.


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## Igor Porto (Jan 14, 2009)

was.lost.but.now.found said:


> I'd be very curious to know what battery was used as their comparison as the standard (non LSD) NiMH.



Probably their standard NiMH batteries. Look the pic on this graph:


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## geek4christ (Jan 26, 2009)

Awesome link roundup, Bones. Thanks for posting.


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## Egsise (Jan 26, 2009)

Bones said:


> The Sanyo Europe website has recently evolved into a trove of information on the Eneloop including plenty of graphs and diagrams.
> 
> Here are hyperlinks to a some of the most relevant pages:
> 
> ...



Kinda "old" news...:thinking: See My post
My link is to this place, i guess those files have been just waiting there to be "found".


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## traveler (Jan 26, 2009)

Very useful!

From the graph, even eneloop drop about 50% of capacity after 300 cycles. 

So if you charge/discharge battery everyday (possible if you use high power DSLR to take photos), about 1 year life span is expected.


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## Black Rose (Jan 26, 2009)

traveler said:


> Very useful!
> 
> From the graph, even eneloop drop about 50% of capacity after 300 cycles.


The charge and discharge rates in that graph are 1C (2000 mA), which is harder on the cells than what most people do; 1000 mA charge, 500 mA discharge.


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## jhellwig (Jan 27, 2009)

Cydonia said:


> This is quite amazing really, when you think about it, this overabundance of information in contrast to the... paucity offered by the "other" manufacturers.
> 
> But being the rotten cynic that I am… I can’t help but suspect we have seen the high water mark of quality LSD NiMh cells embodied in the Sanyo Eneloop. A retrenchment into dubious and sporadic quality equivalents is all but assured in the future according to my pessimists outlook :ironic:
> In other words this is all too good to last.





I would also be suspicious considering that sanyo made junk tv's for walmart for years. They even acknowledged that they were junk. They had a seperate number you called when the thing to a crap.


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## was.lost.but.now.found (Jan 29, 2009)

jhellwig said:


> I would also be suspicious considering that sanyo made junk tv's for walmart for years. They even acknowledged that they were junk. They had a seperate number you called when the thing to a crap.


 
I have a Walmart Sanyo tv from college that is 12 years old and still going strong.


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## Muse (Feb 2, 2009)

Black Rose said:


> Wow, what an amazing amount of information.
> 
> Yeah, lets hope that Panasonic sees fit to keep the Eneloop alive.


Panasonic (and Matsushita in general) is known for quality, durability, long product life. Consumer Reports surveys bore this out some years ago, I don't know about recent studies. Of course, in this economic climate who knows what's going to transpire? However, I just ordered 2 packs of AAA Eneloops (not to predate the Panasonic effect, but because I need some good AAA rechargables).


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## Bones (Feb 3, 2009)

traveler said:


> Very useful!
> 
> From the graph, even eneloop drop about 50% of capacity after 300 cycles.
> 
> ...



When you consider that those poor cells went through a complete 2 Ampere charge and a complete 2 Ampere discharge every 2 hours and 40 minutes for over 40 days and 40 nights, I think they did amazingly well.

This is especially so when you consider that they did it in an ambient temperature of 25°C, with a DeltaV of +/- 10mV, and with a measly 20 minute rest period after charging and an even more measly 10 minute rest period after discharging.

In fact, it's too bad the graph of the test results doesn't also chart the internal temperature of the cells throughout the test. It would be interesting to know the highest and average temperatures the cells had to sustain.

Anyway, as noted on the graph, this was a (grossly) accelerated test, and while it certainly proves the Eneloop can take a beating, I don't think it can be considered in any way indicative of its true cycle life. Except, of course, in an application that somewhat duplicates actual the conditions of the test.


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## LuxLuthor (Feb 3, 2009)

A great resource thread. Thanks Bones and others. Including all the information at that unprotected file resource: http://www.eneloop.info/fileadmin

I love the violations of the Important ReadMe File point "B" !!!

http://www.eneloop.info/fileadmin/IMPORTANT_README.txt


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## Turbo DV8 (Feb 27, 2009)

Muse said:


> Panasonic (and Matsushita in general) is known for quality, durability, long product life.


 
Yeah. I bought an $1800 Panasonic plasma TV. It crapped out one month out of manufacturer warranty. Panasonic deemed it irrepairable, basically said it hoped I enjoyed my $1800 TV for the 13 months it lasted. For the rest of my life, I wouldn't buy so much as a Panasonic toothpick...


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## NiOOH (Feb 27, 2009)

Although a great source of info, I could never stop myself from asking-how accurate are these data? 
Let's have a look at all this from a marketing perspectieve. Eneloop is a major Sanyo brand and a major investment. Aggresive marketing is a must, especially when the LSD technology is not limited to Sanyo. I don't say the data presentesd in these articles are faked, but still there are many ways to present some data and pick samples for comparison.


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## Kaamos (Nov 25, 2009)

Turbo DV8 said:


> Yeah. I bought an $1800 Panasonic plasma TV. It crapped out one month out of manufacturer warranty. Panasonic deemed it irrepairable, basically said it hoped I enjoyed my $1800 TV for the 13 months it lasted. For the rest of my life, I wouldn't buy so much as a Panasonic toothpick...



I have to admit that I also try to avoid Panasonic products, not because of apparent lack of quality, but because of the very disappointing customer care of the country organization here in Finland regarding a faulty product (headphones). There are few things that can be produced without a faulty one here and there, but I think the real difference between manufacturers is in how they handle that fact. A global company should keep an eye on the country representatives to avoid bad image. The country organizations are largely the "face" of the company.

But I guess bashing Panasonic is not the key point here. Are there similar comparisons between different LSD batteries? I mean the fast charge/fast discharge cycle test? I tried the search, found comparisons of capacities and self discharge rates but not durability figures.


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## shelm (Jan 8, 2012)

About the Eneloop Performance Details for Experts, i still wouldnt know what the critical voltage of the Eneloops is before it becomes unhealthy and damaging for the cell. In reviews and runtime tests for low current flashlights (e.g. HKJ's review of Klarux Mi X6) the voltage of the 1.2V NiMH cell goes down to *0.42 Volt* ( I=50mA ) before the light drops out of regulation and gets dimmer:


HKJ said:


> Klarus MIX6 Low : ( ..graph.. ) Low will stabilize down to 0.42 volt.


This voltage is clearly below the official Klarus MiX6 operating voltage of "*0.8V*-1.8V" so i am wondering how we determine when we should recharge the Eneloop in our high performance Cree LED flashlights.

So is there any official *critical Eneloop voltage*? --- Or when do you exchange the cells? In particular, i would be interested in doing some Eneloop runtime tests in my little flashlights.


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## Mr Happy (Jan 8, 2012)

shelm said:


> So is there any official *critical Eneloop voltage*? --- Or when do you exchange the cells? In particular, i would be interested in doing some Eneloop runtime tests in my little flashlights.



If it's a single eneloop in a single cell application, then the critical voltage is 0 V. However the light will stop working before that point is reached.

If there are two or more eneloops in series, then the critical voltage is quite high, maybe 1.1 V, depending on the current draw. You must under all circumstances avoid reverse biasing a cell and forcing it into electrolysis mode. The best advice is to stop and recharge as soon as the light shows any sign of dimming, or if it loses the high or turbo modes. Never run a two cell light to exhaustion.


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## shelm (Jan 8, 2012)

Mr Happy said:


> If it's a single eneloop in a single cell application, then the critical voltage is 0 V. However the light will stop working before that point is reached.
> ...
> Never run a two cell light to exhaustion.


My light(s) are single-cell flashlights. So you're saying that it is safe and (more or less) harmless to run the 1x Eneloop in the flashlight as long as the light produces light (even beyond the point of dimming and until the light stops producing *any* light)?

In the Klarus example, which is a 1x AAA light, there's nothing bad/harmful about ending up with a 0.42V charged Eneloop AAA cell? 

Thanks for your answer!


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## Mr Happy (Jan 8, 2012)

shelm said:


> My light(s) are single-cell flashlights. So you're saying that it is safe and (more or less) harmless to run the 1x Eneloop in the flashlight as long as the light produces light (even beyond the point of dimming and until the light stops producing *any* light)?
> 
> In the Klarus example, which is a 1x AAA light, there's nothing bad/harmful about ending up with a 0.42V charged Eneloop AAA cell?



There is no theory or evidence that this would be harmful to an eneloop. I have not tested that myself, and most people are cautious about doing it since it was harmful to older designs of NiMH cell. But if you do it once or twice by accident or necessity you should not be concerned.


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## AnAppleSnail (Jan 8, 2012)

Sacrifice an eneloop to test this. One CPF member wrapped a few in foil for a week or two and recharged them to see what would happen when his children's toys ran them flat. No apparent harm, but he didn't have a CBA to run them on, either.


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## shelm (Jan 8, 2012)

AnAppleSnail said:


> Sacrifice an eneloop to test this. One CPF member wrapped a few in foil for a week or two and recharged them to see what would happen when his children's toys ran them flat. No apparent harm, but he didn't have a CBA to run them on, either.


Okay, i will sacrifice an eneloop (both AA, and AAA) to test this. Will do repeated runtime tests just with them, i.e. until the light is *very apparently* dimmer than it should be for its mode (Hi - Med - Lo).

Erh, CBA? got no idea what that is


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## AnAppleSnail (Jan 8, 2012)

shelm said:


> Okay, i will sacrifice an eneloop (both AA, and AAA) to test this. Will do repeated runtime tests just with them, i.e. until the light is *very apparently* dimmer than it should be for its mode (Hi - Med - Lo).
> 
> Erh, CBA? got no idea what that is



Charger/battery analyzer, or something. One of the widgets that tells you "This battery too xxxx watts to charge and delivered yyyy mAh on discharge."


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## Mr Happy (Jan 8, 2012)

The C9000 works fine enough for testing eneloops. No need for a CBA.


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