# Eneloop Self Discharge study



## SilverFox

Sanyo started the ball rolling with low self discharge NiMh cells with the introduction of their Eneloop cells. I, along with several others, have been testing these cells for roughly a year now and they seem to be holding up to the manufacturers claims.

Sanyo claims 2000 mAh for their AA cells, and we are finding that to be very close. Sanyo claims that they can be used right off the shelf, and that also seems to be true. Sanyo also claims a cycle life of 1000 charge/discharge cycles. I would love to be in a position to check this out, but, for now at least, we will just have to believe them on this. The final claim is that they will still have 85% of their initial capacity after 1 year of room temperature storage. 

This is what I found:

Here is the initial test data on these cells







You can see that they are very strong performers. I even included the data from the 30 day self discharge for comparison.

I then took a pair of cells and stored them on a shelf in my house. Data was taken at 0, 30, 90, and 180 days. Here is what that data looks like.






You can see that the biggest drop in capacity comes in the first 30 days. After that, things settle down. Looking at the numbers we have about 93% of the initial Amp Hours after 30 days and about 91% of the initial Watt Hours for the same time period. At 90 days we have about 88% of the initial Amp Hours and about 85% of the initial Watt Hours. At 180 days we have about 86% of the initial Amp Hours and about 82% of the initial Watt Hours.

I can easily see how these cells could still have 85% of their initial capacity at the end of a year. I am only going to project out to the year mark because I am going to be using my cells. Someone else can do the 1 year testing…

I did not note the voltage of the cells at 30 and 90 days, but at 180 days each cell was at 1.313 open circuit resting volts.

Update: 3/17/08

I just finished testing a set of 9 cells that I normally use in my Mag85. I set them aside a year ago and just finished testing them. Under a 1 amp load, they came in at 1578 mAh. Initially they came in at 1871 mAh, so you can see that they did not live up to their 85% remaining charge after a year of storage.

However, 84.34% is pretty close...

Several people have reported their self discharge test results and they seem to be quite low for normal NiMh cells. A lot of published information has NiMh cells in the 0.5-1% per day self discharge range. I was seeing around 0.7% per day with several brands of cells, based on short term tests of around 30 days. This seems to still be a little high for healthy cells. The problem 2500 mAh cells will completely self discharge in around 10 days so keep in mind that I do not consider those cells “healthy.”

Here is a graph of NiMh self discharge rates comparing original cell chemistry to the Eneloop cell chemistry.






The 0.7% per day line is pretty close to what I, and others, have reported, but it seems to be pessimistic at 90 days and beyond. 

The question of the suitability of the Eneloop cells for use in a remote control or other low drain device has often come up. We know that the self discharge rate is faster early on, then it tapers off. I was concerned that there would be little difference between the normal chemistry rate and the Eneloop chemistry rate, initially, and there might be little advantage in using the Eneloop cells in applications like this. This study indicates that even at the 30 day self discharge rate, the Eneloop chemistry is a lot better.

Ray (Codeman) ran some discharge tests on some Eneloop cells that had been stored for 12 months. The have a manufacturing date indicating that they are 19 months old. You can find his results in this post.  Thanks Ray.

Unfortunately we don't know how much charge they initially had. Sanyo Europe stated that they were putting around a 70% charge into the cells, and we are assuming that this practice is universal, and has been in place since the cells were first introduced.

MorePower sent me some RayOVac Hybrid cells to check out. Thanks.

I will be following the same testing proceedure I used for the Eneloop cells.

Here are the initial test results.






Here are the results from the self discharge study on the Hybrid cells. I will add data as it becomes available. I am using the same storage and testing conditions as I did with the Eneloop cells. The test results are from a 0.50 Amp test.






The Hybrid cells are better than normal NiMh cells, but not quite as good as the Sanyo cells. 

Cannesahs picked up some GP ReCyko AA cells for me. Thanks Jyrki.

The capacity of the battery was not labeled, so I guessed at 2050 mAh. EDIT: They are labeled as 2100 mAh and 2050 mAh minimum. ENDEDIT These are very strong cells. I was surprised that they almost held up over 1.0 volts at 10 amps. I think the voltage of the Eneloop cells is a little higher, but these are very strong cells. 

Here is the initial data.






It will be interesting to see what their self discharge rate is. Testing in progress...

Here is some test data from the Eneloop AAA cells.






And here is the self discharge study on these cells.






There doesn't seem to be much self discharge between 30 and 90 days. The odd numbers are from slight differences in the cells. I used 4 cells for these tests and rotated them in pairs for the various test periods.

Update 5/23/2009

In March of 2006 I ordered and set aside some AAA Eneloop cells. I just got around to needing them and decided to see what they had left in them as far as capacity goes. Over the last three years they have been stored at room temperature.

They ended up with about 550 mAh left. This is about 74% of their original capacity...

Not too bad...  

Tom


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## Anders

Hello Silverfox.

Thx a lot for your time and effort to do this and all the other tests for us here at CPF.

I just ordered some more Eneloop cells

Useful information as always, thanks again

Anders


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## Codeman

Thanks for all the hard work Tom! I think it's time to start swapping out cells in my hotwire lights.


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## wasBlinded

I have 4 Ray-O-Vac Hybrid cells and 4 Eneloop cels that I did a "Refresh-Analyze" on the MAHA c-9000. I plan to let them sit for 30 days (end of the month) and do a discharge test on them. It will be interesting to see if the Eneloops match your results, and how the Hybrids compare over that period.


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## Robstorch

Great work! But some of us consider it fun using our chargers more often!


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## Brighteyez

Thanks for all the work, Tom. That's great info to have, very useful.


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## Robstorch

Forgot to ask, not sure if you know or not how the eneloops handle fast charging with the Energizer 15 minute charger?


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## coppertrail

Yes, this is really great information. Thanks for taking the time to complete this study


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## Idunno445

Great info SilverFox! Thanks for doing this!

Nick


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## Brighteyez

I think Tom mentioned in another thread that they work fine with the 15 minute chargers, but those chargers do take a toll on the overall life of the batteries.



Robstorch said:


> Forgot to ask, not sure if you know or not how the eneloops handle fast charging with the Energizer 15 minute charger?


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## HashPipeK

Nice to see, I wonder how the Rayovac Hybrids compare.


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## Bearcat

I sure would like to see a heads-up comparision between the Eneloops and Rayovac Hybrids. Hopefully, they will be close to the same, since I loaded up with Hybrids for $3.87 per package of 4-AAs and I used up all 10 of my $5.00 off coupons.


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## Phaserburn

Fantastic work and great news! I am more than happy with this rate of charge retention. Knowing I can count on 86% of a full charge after 6 months is terrific; it takes all of the mental overhead out when trying to remember (or worse, write down) when specific cells were last charged. If you just assume you have around 1.7Ah or so to play with regardless of when they were charged, you'll be in the ball park for your calculated runtimes. Not too shabby.


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## jezzyp

I think that a lot of CPFs will now buy a lot of eneloops - and tell others to buy them.
Its just a shame that Sanyo will never reward Silverfox for massivly upping their sales.
Still at least we appreciate the work done.


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## Bullseye00

It'd be nice to get a comparison of all the major low self-discharge NiMh batteries, but SilverFox is probably tired of super long-term self-discharge testing about now. Maybe if people would donate the the batteries to him, we could persuade him to do another round of testing.


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## dekelsey61

Tom,
Thank you for all your imformation!! Thank you for all your hard work also.
Dan


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## Perfectionist

Great work !

So are the Sanyo 2000mah Eneloop's mah better than the Uniross 2100 mah Hybrio's ??


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## etc

Interesting. So they discharge slower, much slower than conventional Ni-MH.

Question: Given the lower 2,000 MaH capacity, does it mean one will get more recharge cycles than the higher capacity 2700 MaH cells?


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## SilverFox

hello Etc,

Sanyo advertises 1000 cycles, without specifics...

Tom


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## Eugene

etc said:


> Interesting. So they discharge slower, much slower than conventional Ni-MH.
> 
> Question: Given the lower 2,000 MaH capacity, does it mean one will get more recharge cycles than the higher capacity 2700 MaH cells?




They self-discharge slower to be correct. And yes they should last for more cycles, fewer charge cycles is one of the tradeoff's of the higher mAH batteries.

I've bought a few and have had a set in our digicam for a couple weeks now which is so far better than regular NiMH's which would self trigger the low battery after a couple weeks.


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## Canuke

Eugene said:


> They self-discharge slower to be correct. And yes they should last for more cycles, fewer charge cycles is one of the tradeoff's of the higher mAH batteries.



Especially when one factors in the additional charge cycles *necessitated by self-discharge* that the Eneloops won't need.


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## roadie

Silverfox Well Done !! :goodjob: :goodjob: :goodjob: 

Thank you for yr in-depth study of the eneloop, really open my eyes ....

i will be using the eneloop for my upcoming magmod .....

as its hard to source for high discharge nimh which is "cheap" like eneloop as compare to R/C sub C batteries in Singapore ....


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## Phaserburn

Canuke said:


> Especially when one factors in the additional charge cycles *necessitated by self-discharge* that the Eneloops won't need.


 
Very good point. I as many cycles are put on a cell because of self-discharge as actual use.


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## MrAl

Hello,

I see 1000 cycles on most of the NiMH cells i see on the web.
The wording is 1000 cycles to 80 percent capacity.
If this is really true, these are great batteries!
I have by doubts though, but i wont say anything until i've seen for myself.

BTW, in my quest for the best batteries, best flashlight, best LEDs, i forgot to
take the time to say thanks to Tom for all his hard work with the testing of
the various cells...i know it's not easy because i've done some of it myself and
it is very time consuming and you have to make sure you get everything right or
the results will not be valid, so thanks very much Tom for taking the time to
do this, which benefits all of us who care about our lights and cells.


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## SilverFox

Hello Al,

Cycle life is defined as the number of cycles it takes to get to 80% of initial capacity utilizing a standard charge of 0.1 C for 16 hours followed by a 5 hour discharge. All of this is done at standard laboratory temperature conditions.

The Battery Handbook states that NiMh chemistry is good for roughly 500 cycles under these conditions.

Now, if you only do a partial discharge most of the time, your cycle life can exceed 1000 cycles. Duracell did some studies where they charged cells to 85% of full capacity and cycled the middle 60% of the cells capacity. They got excellent cycle life, in the laboratory.

Tom


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## bp044

I agree with MrAl's quest to have the best batteries.flashlights and led's.He does not mention a desire the have the best charger. Iwomder if he and others would help me out with a list of their " best "or favorite chargers.Particularly for use with Eneloop's


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## 3rdDerivative

My results after 6 weeks self-discharge:

Sanyo 2700mha -latest from TD (superlattice alloy EVO) --- 2313
Eneloop AA --- 1782

So 2700 still winning overall at 6 weeks. Hmm. Are these latest 2700mah Sanyo's really that good?

Note: 6 weeks of self-discharge, tested on Maha C9000 at 400ma discharge rate. Storage 72F or lower.


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## paulr

A note on capacity: I just acquired a 4-pack of AAA eneloops (thanks to Coppertrail), mfgr date apparently 8/2006. I put one into a 1aaa flashlight (L0P CE) and ran it to exhaustion, then plopped it into my BC900 (initial voltage displayed: 0.86 V) and fully charged it at 200 mA (C/4 nominal). Total charge taken was 850 mAH which I suspect means the actual capacity of this cell is somewhere south of 750 mAH.

I put a second AAA eneloop in the light and used it for a while, I'd have thought maybe to 50% or so. I then put it in the BC900 and the measured voltage was 1.24V which in my experience with HR-3U AA cells has meant the cell is about ready for a recharge. After a couple hours the cell was at 1.55V and somewhat warm. I thought the BC900 should shut down if the voltage got anywhere near that high. I suspect the BC900 missed termination. Anyway I pulled the cell out and I hope it's not damaged. It's in the light right now and seems to be working ok.


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## Mike abcd

paulr said:


> A note on capacity: I just acquired a 4-pack of AAA eneloops (thanks to Coppertrail), mfgr date apparently 8/2006. I put one into a 1aaa flashlight (L0P CE) and ran it to exhaustion, then plopped it into my BC900 (initial voltage displayed: 0.86 V) and fully charged it at 200 mA (C/4 nominal). Total charge taken was 850 mAH which I suspect means the actual capacity of this cell is somewhere south of 750 mAH.
> 
> I put a second AAA eneloop in the light and used it for a while, I'd have thought maybe to 50% or so. I then put it in the BC900 and the measured voltage was 1.24V which in my experience with HR-3U AA cells has meant the cell is about ready for a recharge. After a couple hours the cell was at 1.55V and somewhat warm. I thought the BC900 should shut down if the voltage got anywhere near that high. I suspect the BC900 missed termination. Anyway I pulled the cell out and I hope it's not damaged. It's in the light right now and seems to be working ok.



I've seen AAA cells hit 1.60 V regualrly charging on the BC-900 without missing termination. I doubt your Eneloop missed charge termination although it was probably close to fully charged.

Mike


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## paulr

Hmm, interesting, I'm more used to AA's and I didn't realize AAA's acted differently. Thanks.


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## Mike abcd

paulr said:


> Hmm, interesting, I'm more used to AA's and I didn't realize AAA's acted differently. Thanks.



I don't think they really behave differently given the same C charge rate. It's just easier to charge AAA cells at a higher C rate than AAs on the BC-900 and I regualrly do. The C rate largely determines terminal voltage.

A lot of the cell heating on the BC-900 and other chargers is due to heat from the charger circuitry. The higher the total charge current, the hotter the charger circuitry, the hotter the cells get. I rarely charge 4 AA cells over 700 mA (~.3 C) on the BC-900 because of this but regularly charge AAA cells at .7 C and higher which causes the higher terminal voltage.

Mike


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## bob_ninja

3rdDerivative,
Comparison of brand new cells doesn't represent the actual user experience as with usage they get damaged, some more and others less. In particular, if you tested Sanyo 2.7Ah vs Eneloop 2Ah AFTER some real world usage (mixed applications) then you would probably find that higher capacity cells sustained more damage and have a faster SD rate compared to Eneloops. Many reported here drastically accelerated SD rate on Energizers, 2.5Ah after less than 100 cycles. No such reports for Eneloops so far (still early though).


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## Perfectionist

To get the best performance from these Eneloop batteries ..... do I need to get the Eneloop charger too ??


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## paulr

Regular charger is fine.


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## 3rdDerivative

bob_ninja said:


> 3rdDerivative,
> ...In particular, if you tested Sanyo 2.7Ah vs Eneloop 2Ah AFTER some real world usage (mixed applications) then you would probably find that higher capacity cells sustained more damage and have a faster SD rate compared to Eneloops. Many reported here drastically accelerated SD rate on Energizers, 2.5Ah after less than 100 cycles. No such reports for Eneloops so far (still early though).




My thoughts also. Right now these are pristine cells as are the Eneloops.


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## 3rdDerivative

Oh, should have added this to my post.

I have a digital wireless outdoor thermometer. Last year I noticed on really cold days I would sometime lose the signal. Thought about using AAA lithium, but need does not justify price. So tried the AAA Eneloops starting around November or late October. Just pulled these out and ran a discharge cycle. Still 650mah+ and no lost signals with -1F low so far.

Very impressed.


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## SilverFox

Hello Mike,



Mike abcd said:


> I've seen AAA cells hit 1.60 V regualrly charging on the BC-900 without missing termination. I doubt your Eneloop missed charge termination although it was probably close to fully charged.
> 
> Mike


[/quote]

Interesting...

I don't see high termination voltages with AAA cells until charging at around 2 C. I have seen high voltages when cells develop higher impedance. It would seem you have some high impedance cells...

That might also explain why your cells heat up so much while charging.

Tom


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## SilverFox

Hello Paulr,

If you still know what cell that was that reached 1.55 volts, mark it. It will be interesting to see how it "ages."

Tom


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## Sub_Umbra

Wow, thanks Tom.


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## Raptor#

Thanks Tom!




Bearcat said:


> I sure would like to see a heads-up comparision between the Eneloops and Rayovac Hybrids. Hopefully, they will be close to the same, since I loaded up with Hybrids for $3.87 per package of 4-AAs and I used up all 10 of my $5.00 off coupons.


Yupp. There are a few other long-lasting NiMh's now, wich followed shortly after the eneloops... "Ready2Use" from Varta, "maxE" from Ansmann.. and at www.swissbatteries.com they claim 2500mAh at 1,2-1,4V.


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## coppertrail

Something interesting along the lines of Eneloop cells. I have a couple sets of AAA Eneloops. I've charged one set twice in my MH-C800S, and all cells, off the charger, registered 1.35V on the multimeter. Over the weekend, I treated my charger contacts with DeoxIT (the ones that needed it) and DeoxIT Gold. 

I charged up my AAA Eneloops in the C800S tonight, and each cell registered 1.44V off the charger.


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## SilverFox

Hello Chris,

Everyone could benefit from your example. A cardinal rule in electronics is to keep contacts clean and minimize contact resistance.

Tom


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## paulr

SilverFox said:


> Hello Paulr,
> 
> If you still know what cell that was that reached 1.55 volts, mark it. It will be interesting to see how it "ages."
> 
> Tom


Will do, thanks!


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## Mike abcd

SilverFox said:


> Hello Mike,



Interesting...

I don't see high termination voltages with AAA cells until charging at around 2 C. I have seen high voltages when cells develop higher impedance. It would seem you have some high impedance cells...

That might also explain why your cells heat up so much while charging.

Tom[/QUOTE]

Nice cheap shot Tom. Can we keep C-9000 discussions in the C-9000 thread?

If you're charging NiMH at 2C, you're likely to be the one with the high impedance cells.

The 1.60 V was a LaCrosse 700 mAH charged at 700 mAH and, relatively speaking, was probably "high impedance".

My Energizer 850 AAA hit 156-1.57 V @ 700 mA in the BC-900 which appears to read higher at equivalent charge currents than the C-9000. They have ~30-50 cycles on them but have been treated very well and get to about 115 deg F on the BC-900 charged singly @ 700 mA. They test north of 830 mAH on a recent check @ 500 mA. They function as well as when they were new IMHO at 1C on high in my L0P SE and L0D CE.

I'm not sure what my Powerex 1000 mAH AA hit in the BC-900 @ 700 mA just before termination but I've seen 1.53 V.

Must we blame everything on bad cells?

Mike


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## Mike abcd

SilverFox said:


> Hello Mike,
> 
> Interesting...
> 
> I don't see high termination voltages with AAA cells until charging at around 2 C. I have seen high voltages when cells develop higher impedance. It would seem you have some high impedance cells...
> 
> That might also explain why your cells heat up so much while charging.
> 
> Tom



Nice cheap shot Tom. Can we keep C-9000 discussions in the C-9000 thread?

If you're charging NiMH at 2C, you're likely to be the one with the high impedance cells.

The 1.60 V was a LaCrosse 700 mAH charged at 700 mAH and, relatively speaking, was probably "high impedance".

My Energizer 850 AAA hit 156-1.57 V @ 700 mA in the BC-900 which appears to read higher at equivalent charge currents than the C-9000. They have ~30-50 cycles on them but have been treated very well and get to about 115 deg F on the BC-900 charged singly @ 700 mA. They test north of 830 mAH on a recent check @ 500 mA. They function as well as when they were new IMHO at 1C on high in my L0P SE and L0D CE.

I'm not sure what my Powerex 1000 mAH AA hit in the BC-900 @ 700 mA just before termination but I've seen 1.53 V.

Must we blame everything on bad cells?

Mike


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## SilverFox

Hello Mike,

I think you are confused… We are talking about Eneloop cells and high voltages while charging. I am not sure how you jumped from that to the C9000… Let’s try to stay on track.

I regularly charge my Mag85 battery, that has Eneloop cells in it, on my Schulze charger at 4 - 5 amps. The ending voltage climbs up to around 13.14 volts. This works out to around 1.46 volts per cell. When I charge at lower rates, the ending voltage is around 1.45 volts per cell.

The impedance of the cells in my pack are all under 0.030 ohms. The started out at 0.025 ohms, so I think they still qualify as lower impedance cells.

AAA cells have higher impedance than AA cells. This means that they will come off the charger at slightly higher voltages, but I think 1.6 volts is pushing it. The cell impedance goes up a little at the end of the charge, so we also have to factor that in as well.

Keep in mind that we are talking NiMh cells here. NiCd cells end up with voltages in the 1.6 – 1.8 volt range, or higher.

I see voltages in the 1.45 – 1.47 volt range when charging AAA cells, with the higher impedance cells registering higher voltages. I have also noticed that cells seem to register a higher voltage on the BC-900 and have seen AAA cells terminate at 1.53 volts on it.

Higher impedance cells are not necessarily bad. They have problems when used or charged at high current rates because of the heat generated due to the higher resistance, but function very well in moderate or low drain applications.

For what it is worth, and off topic, my 700 mAh LaCrosse AAA cells terminate at 1.47 volts on the LaCrosse when charging at 700 mA, and at 1.46 volts when charging on the C9000 at 1400 mA. The impedance of these cells is under 0.040 ohms.

To move back on topic again, people on CPF have reported a lot of differences in the performance of the cells they have, while charging and while in use. Some people end up with hot cells, others don’t. Most of us are using the same equipment. Why is this so?

If I didn’t know better, it almost sounds like you are suggesting that cell condition does not influence performance… The Eneloop cells are new, and it seems that almost everyone is having consistent results with them.

Tom


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## Mike abcd

SilverFox said:


> Hello Mike,
> 
> I think you are confused… We are talking about Eneloop cells and high voltages while charging. I am not sure how you jumped from that to the C9000… Let’s try to stay on track.
> 
> I regularly charge my Mag85 battery, that has Eneloop cells in it, on my Schulze charger at 4 - 5 amps. The ending voltage climbs up to around 13.14 volts. This works out to around 1.46 volts per cell. When I charge at lower rates, the ending voltage is around 1.45 volts per cell.
> 
> The impedance of the cells in my pack are all under 0.030 ohms. The started out at 0.025 ohms, so I think they still qualify as lower impedance cells.
> 
> AAA cells have higher impedance than AA cells. This means that they will come off the charger at slightly higher voltages, but I think 1.6 volts is pushing it. The cell impedance goes up a little at the end of the charge, so we also have to factor that in as well.
> 
> Keep in mind that we are talking NiMh cells here. NiCd cells end up with voltages in the 1.6 – 1.8 volt range, or higher.
> 
> I see voltages in the 1.45 – 1.47 volt range when charging AAA cells, with the higher impedance cells registering higher voltages. I have also noticed that cells seem to register a higher voltage on the BC-900 and have seen AAA cells terminate at 1.53 volts on it.
> 
> Higher impedance cells are not necessarily bad. They have problems when used or charged at high current rates because of the heat generated due to the higher resistance, but function very well in moderate or low drain applications.
> 
> For what it is worth, and off topic, my 700 mAh LaCrosse AAA cells terminate at 1.47 volts on the LaCrosse when charging at 700 mA, and at 1.46 volts when charging on the C9000 at 1400 mA. The impedance of these cells is under 0.040 ohms.
> 
> To move back on topic again, people on CPF have reported a lot of differences in the performance of the cells they have, while charging and while in use. Some people end up with hot cells, others don’t. Most of us are using the same equipment. Why is this so?
> 
> If I didn’t know better, it almost sounds like you are suggesting that cell condition does not influence performance… The Eneloop cells are new, and it seems that almost everyone is having consistent results with them.
> 
> Tom



Tom,

The discussion is on the voltage displayed by the BC-900 while charging and not the voltage after charging has completed.

From the Sanyo NiMH doc.
http://123pichosting.com/images/4945NiMH_V_vs_Charge.jpg





Click on the link or thumbnail for the full size image.

Even at .5 C Sanyo shows cell voltage around 1.52 and ~1.56 V at 1C while under charge.

My reported results are very close given that we've both observed the BC-900 seems to read a little high. I doubt Sanyo used cells exhibiting high impedance to generate the data.

" That might also explain why your cells heat up so much while charging."

That's where you dragged in the C-9000 cell heating discussion. I never mentioned that my cells get hot in this thread, only that I see higher temps with a higher load on the charger due to more heat from the charger circuitry. Regretfully our exchanges are getting progressively more ugly but I have little tolerance for childish games.

I just checked a Maha Powerex 1000 mAH that has about 5 cycles on it. At 700 mA (.7C), it hit 1.54 V shortly before terminating. I've seen 1.47 V under charge on an Energizer 2500 charging at 200 mA, )<.1C) again very close to what the cell manufacturer's show.

I have some unopened AA and AAA Eneloops. Please confirm that your posted voltages are while charging and I'll try a test on my BC-900. Frankly I don't believe your Eneloops are only reaching 1.47 V while BEING CHARGED at >2 C.

Mike


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## wasBlinded

I see no evidence of ugliness or childishness on Tom's part in this thread. I'll bet if posters could keep the emotionally charged appellations out of their posts things would probably remain civil.


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## SilverFox

Hello Mike,

You are correct. The Sanyo data does show roughly 1.56 peak voltage when charging HR-4/5AU cells. However the Sanyo data for HR-AAC cells shows a peak of around 1.52 volts, and the Sanyo data for HR-4/3FAUP shows a maximum voltage of around 1.49 volts. Unfortunately the cells that we are using are the HR-3U and HR-4U (AAA and AA) and there is no data presented on those cells.

Yes, I do understand that we are talking about voltage while charging. Resting voltage is usually around 1.42 volts, or lower.

It will be interesting to hear what you are getting with the Eneloop cells. Perhaps others can also post what they are getting when charging their Eneloop cells so we can get a broad basis for comparison.

Let’s start with discharged cells and charge the AA Eneloop cells at 1000 mA and the AAA Eneloop cells at 500 mA, and we will use the BC-900 for charging.

Tom


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## paulr

I should add or emphasize, that the high voltage I saw on my BC900 was at 200 mA or nominal 0.25C. The low charge rate was why I thought maybe the charger had missed termination.

I notice something else, that with AA eneloops my Canon A530 digicam and my Nexblack mp3 player both signal low battery voltage when there's plenty of charge left in the cells, as if the voltage starts sagging under load quite early. I haven't made measurements. I don't have experience with other types of cells in the Nexblack yet, but this did NOT happen with 2500 mAH HR-3U's in the digicam.


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## Mike abcd

paulr said:


> I should add or emphasize, that the high voltage I saw on my BC900 was at 200 mA or nominal 0.25C. The low charge rate was why I thought maybe the charger had missed termination.
> 
> I notice something else, that with AA eneloops my Canon A530 digicam and my Nexblack mp3 player both signal low battery voltage when there's plenty of charge left in the cells, as if the voltage starts sagging under load quite early. I haven't made measurements. I don't have experience with other types of cells in the Nexblack yet, but this did NOT happen with 2500 mAH HR-3U's in the digicam.



Paul,

Charging at 200 mA, it's quite likely that it missed termination. Pardon me for not asking.

I've seen cells terminate at below .1C on the BC-900 when doing a slow charge test but I was surprised and would never depend on it. Above .3 C I've never had it miss a termination except on ancient NiCads and NiMH that had sat at 0 volts. .5 C and above is safer but IMHO, it gets the batteries too hot when charging 4 at higher rates. I don't even like the temps at 1500 mA with 2 cells in the outer slots.

I'm really surprised at your results in your camera. Perhaps Tom will venture a guess.

Mike


----------



## Mike abcd

SilverFox said:


> Hello Mike,
> 
> You are correct. The Sanyo data does show roughly 1.56 peak voltage when charging HR-4/5AU cells. However the Sanyo data for HR-AAC cells shows a peak of around 1.52 volts, and the Sanyo data for HR-4/3FAUP shows a maximum voltage of around 1.49 volts. Unfortunately the cells that we are using are the HR-3U and HR-4U (AAA and AA) and there is no data presented on those cells.
> 
> Yes, I do understand that we are talking about voltage while charging. Resting voltage is usually around 1.42 volts, or lower.
> 
> It will be interesting to hear what you are getting with the Eneloop cells. Perhaps others can also post what they are getting when charging their Eneloop cells so we can get a broad basis for comparison.
> 
> Let’s start with discharged cells and charge the AA Eneloop cells at 1000 mA and the AAA Eneloop cells at 500 mA, and we will use the BC-900 for charging.
> 
> Tom



Tom,

Where did you find the other Sanyo cell data?

Just did a quick test. Cut open an unused pack of 4 AAA Eneloops. 3 of 4 measured 1.311, the 4th 1.312. Production date of 08/2006 purchased from HH Gregg on 11/30/06 and left sitting unopened at ~70 deg F room temp since being received. Never dropped by me and certainly not damaged in shipment as they were packed in a huge box filled with peanuts.

Put one of the 1.311 V ones on the BC-900 to charge at 1000 mA (1.25C). Frankly I was thinking of the Maha 1000 mAH AAA I was using recently or would have charged at 700 mA.

Cell took 218 mA. The BC-900 displayed voltage peaked at 1.56 V for several minutes and then dropped to 1.55 V shortly before it terminated.

I wouldn't be suprised at a slightly lower peak voltage starting with a fully discharged cell but keep in mind that this cell wasn't completely charged either.

Why are you suggesting testing at .5/.625 C when we're comparing your results at 2.5C?

I logged voltage with my RS DMM and it showed ~.1 V higher than the BC-900 displayed.

Do you think I induced high impedance in this cell by touching it? That would explain you being right about all my other batteries. Maybe I'm just unlucky and got the first Eneloop duds reported here?

Mike


----------



## SilverFox

Hello Mike,

Here is the Sanyo data.

Very interesting results. Perhaps your BC-900 missed the termination... 

My suggested test settings were designed to be reasonable with respect to these cells. I do not recommend charging at high rates, unless you have a proven charger that keeps very close control of things, and even then it is at your own risk. The charging rates that I specified for the testing can be used by anyone using the BC-900, with minimal risks of missed termination.

It will be interesting to see what you come up with when charging at 1000 mA for AA Eneloop cells and 500 mA for AAA Eneloop cells.

Keep us informed of your results. I am discharging some AA and AAA cells right now.

Tom


----------



## Billson

I keep reading about the self discharge of Eneloops but it just occured to me that I've never read a discussion about the memory effects of the Eneloops? Do they need to be discharged first before recharging to achieve full capacity?


----------



## SilverFox

Hello Billson,

I believe they are just like other NiMh cells. Every 20 - 25 cycles or so they should be fully discharged.

Tom


----------



## paulr

Memory effect is sort of a myth and Eneloops are almost certainly conditioned before shipping. However they apparently usually do not arrive in a state of 100% charge. More like 75% or so.


----------



## SilverFox

Here are my test results...

I took 4 Eneloop cells, 2 AA and 2 AAA, and discharged them. I let them rest for 30 minutes, the placed the AA cells in slots 1 and 2, and the AAA cells in slots 3 and 4 of the BC-900.

Charging the AA cells at 1000 mA resulted in a maximum voltage of 1.52 and 1.51 volts. Maximum temperatures were 104 F and 110 F.

Charging the AAA cells at 500 mA resulted in a maximum voltage of 1.52 and 1.52 volts. Maximum temperatures were 115 F and 112 F.

I then discharged the cells again and charged them on the C9000.

The maximum voltage for all 4 cells was 1.51 volts.

Maximum temperatures were 102 F, 108 F, 110 F, and 104 F.

It is interesting to observe that the cell temperatures, at these charging rates, were lower on the C9000 than they were on the BC-900.

The voltages were higher that I was expecting.

These cells have been in use in my camera and flash for the past year. I would guess that they have 5 - 6 cycles of use on them.

Tom


----------



## Perfectionist

Is it worth getting 2000mah AA Eneloops now ..... or will we see 2500mah coming out soon ??


----------



## coppertrail

I've felt that my Eneloop purchases have been worthwhile, and I've not seen any mention of higher capacity Eneloop cells in the works.


----------



## Raptor#

I've seen what is advertised as 2500 mah Slow-discharge NiMh (eneloop-alike) here:
http://www.swissbatteries.com/dynaPage.asp?mPage=SwissBatteries

They sell a 4-pack of AA's for $13. Personally, im a bit sceptical about theyr claims...


----------



## Billson

SilverFox said:


> Here are my test results...
> 
> I took 4 Eneloop cells, 2 AA and 2 AAA, and discharged them. I let them rest for 30 minutes, the placed the AA cells in slots 1 and 2, and the AAA cells in slots 3 and 4 of the BC-900.
> 
> Charging the AA cells at 1000 mA resulted in a maximum voltage of 1.52 and 1.51 volts. Maximum temperatures were 104 F and 110 F.
> 
> Charging the AAA cells at 500 mA resulted in a maximum voltage of 1.52 and 1.52 volts. Maximum temperatures were 115 F and 112 F.
> 
> I then discharged the cells again and charged them on the C9000.
> 
> The maximum voltage for all 4 cells was 1.51 volts.
> 
> Maximum temperatures were 102 F, 108 F, 110 F, and 104 F.
> 
> It is interesting to observe that the cell temperatures, at these charging rates, were lower on the C9000 than they were on the BC-900.
> 
> The voltages were higher that I was expecting.
> 
> These cells have been in use in my camera and flash for the past year. I would guess that they have 5 - 6 cycles of use on them.
> 
> Tom



Hi Tom,

What's your ambient temperature? I have never been able to charge at 1A without it shutting down from thermal cutoff unless I have fan blowing on it. Our ambient temp is usually around 30C (86F).


----------



## SilverFox

Hello Bill,

Room temperature is around 68 F (20 C) at my house.

Tom


----------



## LittleBrownStain

Sanyo's Eneloops; Uniross's Hybrios; RayOVac's Hybrids; AccuPower's AccuLoops; and no doubt, many more to follow.

_Finally!_ We seem to be entering a new, welcome and most-overdue chapter in the evolution of NiMH cell technology. Long-shelf life, slow-self-discharge cells. We've been wanting and waiting for them for years. How long, now, before (reg'lar) NiMH technology goes the way of NiCads and the Do-Do birds? According to a news piece I read, RayOVac had planned to discontinue ALL further manufacturing of their (regular) NiMH cells the first of this year, (their 15 Min IC-3's are already history) to concentrate solely on their new Hybrids. 

In the wake of the kind and upbeat info Silverfox and others have presented here, coupled with (I hope) public awareness, how long now before mainstreamers Duracell and Energizer jump on the bandwagon?

I just bought my first six Eneloop AA cells the other day (2 Ea. mnfg Oct/06, and 4 Ea, mnfg Jun/06) - they all tested at 80%+ full out of the package on my ZTS mini-mbt tester (I have nothing more sophisticated right now), and of course, they work just perfectly.

Very Happy Indeed!


----------



## Eugene

Yes, they are finally where they should have been years ago. I had completely given up on rechargeables due to the NiMH self discharge issues. I now have 36 Eneloop cells in various gear


----------



## MrAl

Hi there,

I am sort of waiting until they show up locally around here for a decent price.
I have many 'standard' NiMH cells to use up first anyway.


----------



## Sub_Umbra

I just hope Eneloops are available in Cs and Ds (and not just fluffy AA adaptors) before the *Green NAZI's* make NiCads illegal. I'd switch over TODAY.


----------



## SilverFox

Hello Sub Umbra,

I have it on very good authority that Eneloop cells will not be available in C and D sizes, and on not as good authority that the capacity may not go up...

Better stock up on your NiCd cells...

Tom


----------



## hburner

Got me some of those eneloopers and I must say that so far I am impressed. In a 9AA holder they came off the charger at 13v.

After 8 hours they were still at 13v.

16 hours later they tested at 12.91

@ 21 hours later they finally fell to 12.6v, after that I just put them back on the charger and discharged them to an acceptable voltage for my [email protected].

They WILL also fit in a Modamag 8AAto2D holder and slide right in a 2D mag no problem, I have been looking for a set of batts that would fit and the eneloops are doing pretty darn good, now I just need about 20 more loops.


----------



## WildChild

C/D size would be nice but they wouldn't make much profit with them since AA and AAA are probably the most popular! As for the capacity, 2000 mAh is enough and they should probably stay at this mark!  Also, 2000 is a nice round number. 



SilverFox said:


> Hello Sub Umbra,
> 
> I have it on very good authority that Eneloop cells will not be available in C and D sizes, and on not as good authority that the capacity may not go up...
> 
> Better stock up on your NiCd cells...
> 
> Tom


----------



## Eugene

hburner said:


> Got me some of those eneloopers and I must say that so far I am impressed. In a 9AA holder they came off the charger at 13v.



Did you charge them all individual, or do you have a series charger?


----------



## hburner

Did you charge them all individual, or do you have a series charger?

I had them in a Fivemega 9AAto3D holder and put my MAHA C777PLUS-II to discharge and then it recharged them.

This was right out of the packs and the first charge on them, straight out of the pack every cell read 1.36v, every one the exact same thing.


----------



## LittleBrownStain

Any updates, guys?

(Sorry, I had to post _something _here), so that I could tick-off the 'instant email notification' box below, which I forgot to do last time.


----------



## LuxLuthor

I got 4 packs of 4 2000mA Eneloops AA when I got my C6000 charger from Maha, and because they are a new type of battery, what is the guideline as far as initial conditioning as compared to other new NiMH's?


----------



## coppertrail

Hi Lux - It does not appear that eneloop cells benefit from a break in cycle, I would just charge and use. You may see better results after the first few charge/discharge cycles.


----------



## LuxLuthor

coppertrail said:


> Hi Lux - It does not appear that eneloop cells benefit from a break in cycle, I would just charge and use. You may see better results after the first few charge/discharge cycles.



Sweet! I was hoping that would be the case.


----------



## jayflash

My experience with only four Ray O Vac Hybrid AA cells it that their capacity and voltage maintenance under load improved after three charge/discharge (1v) cycles. This may not be true for Sanyo.


----------



## matrixshaman

Could anyone let me know some good sources and prices for AA Eneloops? I've just recently decided to get some new AA NiMH's since all I've got now are 1200 mah Energizers from several years ago - which still seem to work but not a lot of run time. Thanks SilverFox for all your battery testing and charting!


----------



## coppertrail

Do you live in the US?


----------



## Eugene

If your in the US, currently HHGreg has the cheapest price at $9.99 or sometimes marked $7.99 for a 4 pack of AA's. And no, they are not a renamed SunTV (for those that don't know there was a small midwest chain called suntv that totally ripped many people off so some people won't shop at hhgreg because they bought out a couple of the old suntv stores a couple years after they went under). Thomas Distributing has the next best price.


----------



## Sub_Umbra

I got mine from HHGreg a few months ago and it was a great price with free shipping. There were a few who had trouble with their orders but they seemed to straighten out and mine was flawless. Very quickly shipped. No surprises. I was able to order more than I thought I could because their deal at the time was so good. I would recommend them.


----------



## coppertrail

HHGregg no longer has the eneloop cells on their site . . .


----------



## Norm

I purchased 2 sets of 2 eneloop batteries some months ago for a Sony camera that is used very intermittently, in the past every time I went to use the camera the Ni-MH batteries would be flat, I am still on the first set after about three months intermittent use and they still show full on the camera. I have yet to charge either set.
Norm


----------



## roadie

in near future, when i will be building a battery pack for many devices to be use while hiking or camping, i think i shall stick to Eneloop  [ pack in serials + parallel]

the ability to hold charge is a wonder , hope they(sanyo) invent C and D cells ..... (keeping my fingers cross) ..... i can wait a decade ,


----------



## LuxLuthor

I'm pretty sure HH Gregg only had that one batch several months ago, as I have checked back a number of times. Problem is they don't have a website search feature to make sure they don't have them listed under some special area.


----------



## Eugene

They are still in the stores, at least they were a couple weeks ago when I picked up some AAA's


----------



## coppertrail

Right, I picked up a few packs last week. Looks like they grew tired of folks calling in and asking why they wouldn't ship them


----------



## dekelsey61

Has anyone ever called hhgregg and see why they stopped shipping them?
Thank you.
Dan


----------



## matrixshaman

coppertrail said:


> Do you live in the US?


Colorado - unfortunately it appears they are only in the SE US. Maybe I'll give them a call to see if they still have them. eBay prices on these are not very good with shipping. Isn't Thomas Distributing just a huge place listing 1000's of smaller businesses? Thanks guys for the help on this.


----------



## coppertrail

Thomas-Distributing is its own company, they sell batteries and battery equipment such as chargers, testers, and cases. I've done quite a bit of business with them and must say their customer service is excellent.


----------



## LittleBrownStain

coppertrail said:


> Thomas-Distributing is its own company, they sell batteries and battery equipment such as chargers, testers, and cases. I've done quite a bit of business with them and must say their customer service is excellent.



Ditto.

And I live in Canada. They shipped my ZTS mini-mbt tester and 4 Acculoop AAs immediately; they offer Eneloops at less than half the price I had to pay at retail here in Canada, they have some _killer _products, they included a FREE discount coupon for my next order, they accept PayPal, and their customer service (called *customer care*) is the very best I have seen anywhere.

If you call their toll-free customer care line, you receive an immediate _real-life person, _not an answering machine with a voice-menu to wade through; if you email them, you can expect a reply on the next business day. I'll be ordering from them again.


----------



## LittleBrownStain

hburner said:


> .... They WILL also fit in a Modamag 8AAto2D holder and slide right in a 2D mag no problem, I have been looking for a set of batts that would fit and the eneloops are doing pretty darn good, now I just need about 20 more loops.



Yikes! You _may _be the guy I need to talk to, hburner!

I just bought a MagLite 2D-LED (a freeking wonderful flashlight!), but I want to power it with eneloops. I don't have the Modamag 8AAto2D holder you mention above, but I do have a couple of lesser 1AA to D adaptors (Panasonic) fitted with eneloop AA's. I'm using them right now in the Mag2D, but only with the crummy incandescent bulb.

I'm told NOT to use rechargeables with the Mag LED module. I guess I risk frying the module if I try. Without having to resort to, say, paying $40 for the (admittedly wonderful) EverLED module, do you know of any (hopefully simple) mod that will get the MagLED module to accept NiMhs like the eneloops? -Thnx!-


----------



## LittleBrownStain

Problem now solved, thanks to members *macdude22 *and *eebowler.

*The Mag2D works _perfectly _with 2 AA eneloops sitting in 2 AA-To-D adaptors. No, they won't last as long as 2 D cells, but then, I have a bucket-full of AAs, y'know? 

So much for MagLite's warning not to use rechargeables.


----------



## WildChild

I used my MAG-LED 2D with 2 AA NiMH in 1AA to D adapters without any problem! Anyway, there is a circuit in this drop-in for constant current output... Like some said, this warning was probably there for incandescent bulbs that may fry with NiMH/NiCD and they just copied the text for their MAG-LED bulbs.



LittleBrownStain said:


> Problem now solved, thanks to members *macdude22 *and *eebowler.
> 
> *The Mag2D works _perfectly _with 2 AA eneloops sitting in 2 AA-To-D adaptors. No, they won't last as long as 2 D cells, but then, I have a bucket-full of AAs, y'know?
> 
> So much for MagLite's warning not to use rechargeables.


----------



## Brighteyez

If you're referring to the portion on the Mag packaging about not using rechargeable batteries, that text has been there for many years on their incandescent bulbs, and on the documentation for their lights. It was also carried over to the product documentation, verbatim, for the LED products. 
The level of caution that you should yield to this content is up to your own discretion. Personally, I chose to ignore it.



WildChild said:


> Like some said, this warning was probably there for incandescent bulbs that may fry with NiMH/NiCD and they just copied the text for their MAG-LED bulbs.


----------



## Chinook

Brighteyez said:


> If you're referring to the portion on the Mag packaging about not using rechargeable batteries, that text has been there for many years on their incandescent bulbs, and on the documentation for their lights. It was also carried over to the product documentation, verbatim, for the LED products.
> The level of caution that you should yield to this content is up to your own discretion. Personally, I chose to ignore it.



You choose to ignore the manufacturer warning on the packaging? Seems like... o never mind...


----------



## LittleBrownStain

WildChild said:


> I used my MAG-LED 2D with 2 AA NiMH in 1AA to D adapters without any problem! Anyway, there is a circuit in this drop-in for constant current output... Like some said, this warning was probably there for incandescent bulbs that may fry with NiMH/NiCD and they just copied the text for their MAG-LED bulbs.



*Bonjour, WildChild, mon ami! * Je ne comprend pas la (French), mais je ...
(....try, oh I do try, but I'm no dang good at it). 

Isn't it strange? I might wade through a football-field's-worth of threads in here for a week to find a single answer to a single question, and then directly ask, in about a dozen, different veiled ways, the same question - all to no avail, and _then ...

*Poof! *_Five different folks give me the same (hoped for) answer in a 24-hour period! (Nature of the CPF Beast, I guess).  It's kind of like that line in one of James Taylor's songs - _"I guess it's true what they say about the squeaky wheel, always getting the grease." -- ['Shower The People']_

Yep - the rechargeables work fine, as you have said. I want to use the eneloop's (or other LSD's) slow-self-discharge properties as much as possible in devices that can best take advantage of them - flashlights certainly qualify. I don't expect to be buying another (reg'lar) NiMH cell.

Some folks think I'm ... (well, ...) nuts for feeding a D cell flashlight with piddly lil' AA cells - well *I* say, _Sanyo's_ nuts for not coughing up *proper* D-size eneloops to begin with. 

(But no, I've never had a problem feeding a crummy incandescent bulb with either a NiCad or NiMH cell, but who the hell wants incans anymore??)

Since the advent and general availibility of LED's, (hold me back here, WildChild).... _Merciful Mother of Mary! I has *seen the light!* - Lawdy, Lawdy Miss Clawdy! :laughing:

_I figured youze guys would eventually pull through if I bugged ya long enough!

_Au revoirs pour maintenant, WildChild, dans la belle province! 

_-- Mike --


----------



## LittleBrownStain

Brighteyez said:


> If you're referring to the portion on the Mag packaging about not using rechargeable batteries, that text has been there for many years on their incandescent bulbs, and on the documentation for their lights. It was also carried over to the product documentation, verbatim, for the LED products.
> The level of caution that you should yield to this content is up to your own discretion. Personally, I chose to ignore it.



Well, if so, the MagLite people ought to know better than to offer old advice on the packaging of new devices/technology. From what I've been reading in here about the new Mag 2-3-&-4-cell drop-in modules, MagLite hasn't exactly been keeping up with the times anyway. (Number #1 boondoggle = *no *heatsinking to a *huge* aluminum host body). They certainly could have taken advantage of that, but chose instead to use (aging) electronics, which in turn, plummets available light output after about 15 mins. 

But I like the light (very much) anyway, and and even AA cells will run an LED for a l-o-n-g time.


----------



## matrixshaman

Thanks again to coppertrail - I've now got some AA eneloops for a good price and all only 4 days after asking about them here! Cheers coppertrail !
( http://candlepowerforums.com/vb/showthread.php?t=156404 )
And thanks again to Silverfox for all his work on battery studies.


----------



## SilverFox

Update:

I added the initial test results for the RayOVac Hybrid cells to the first post. 

Tom


----------



## javafool

Thanks Tom! From the graphs, it looks like someone is hiding the 100 extra mAh?


----------



## chimo

Thanks for the great data, Tom! 

I just picked up a set of 8 Eneloops AAs at The SourceCC for C$22 and change. I may have to go back and pick up another 8. 

Paul


----------



## SilverFox

Update:

I just added the 30 day results for the Hybrid cells.

Tom


----------



## TorchBoy

Tom, are you going to add the RayOVac Hybrid results to the self discharge graph? At about 86% after 30 days they don't seem much better than 0.7% discharge.


----------



## SilverFox

Hello Ian,

Yes, in another 6 months or so I will finish the Hybrid testing and will add a line in the graph for them.

Tom


----------



## Anders

Hello Tom.

Now you can do a 90 days test on the hybrid cells:wave:

I am interested of the results (if you have time to do it course)

Just a reminder from me that 90 days are passing.




Anders


----------



## VidPro

Silverfox,
question about the graph (mabey already asked)
the voltage under load is also lower after time too right?
is that Relative to the reduced capacity, or is there also a bit less vibrance to the cell too, umm more voltage drop, weakness, resistance, or whatever you wanna call it.


----------



## SilverFox

Hello VidPro,

The lower voltage is the result of a lower state of charge. The cells are still "vibrant" when fully charged.

Tom


----------



## VidPro

SilverFox said:


> Hello VidPro,
> 
> The lower voltage is the result of a lower state of charge. The cells are still "vibrant" when fully charged.
> 
> Tom



thanks


----------



## SilverFox

Update:

I added the results from the Hybrid AA 90 day test results. It looks like the self discharge rate declines after 30 days.

Tom


----------



## UnknownVT

SilverFox said:


> Update: I added the results from the Hybrid AA 90 day test results. It looks like the self discharge rate declines after 30 days.


 
Thanks for your good work Tom/SilverFox -

Have you looked at the Kodak Pre-Charged AA?

Chevrofreak found them to have good capacity -
ref: Post #*15* in this thread - My Eneloops charge to and hold a higher voltage than other LSD's 
and his graphs of comparing capacities between the Kodaks, standard Duracell 2650mAh NiMH, and Uniross Hybrio -
Posts #*13* and #*14* in new Kodac "Pre Charged" NiMH batteries?

Kodak Pre-Charged at WalMart


----------



## SilverFox

Hello Vincent,

I have not looked at the Kodak cells.

I also understand that Radio Shack is supposed to have their brand of LSD cells as well. I haven't checked those out either, but a friend of mine just got some. I will check in with him from time to time to see how they are doing.

Tom


----------



## VidPro

it is interesting that the hybrids have a lower voltage at the .5-1amp, and that the actual Watt hours between the 2 of them isnt that much different.
depending on the application, and driver, and regulation capacity of driver and all, it could mean something??? i donno.

am i Mixing things up here ? or does the enloopy thing have More actual total power in Wattage at the 1amp, from day 1 to day 90. not Amps at some voltage , but total watts.

you seeing that? i mean when we want the most ammount of total power and the ones marked higher dont HAVE more power to begin with.
if the driver a person is using is magically perfectally flat regulated, then the extra 100ma dont mean squat, according to the chart there is the SAME WATTS in them.
if the driver is the usual loose regulation that were getting, the tiny bit of extra voltage would mean a slightly brighter light.

I donno? but now that more of your results are in, i just tried to Draw a line from the voltages WHICH i noticed are Drooping after the TIME also.
WHY 
well because the 2100 vrses the 2000 is so DANG tempting, i see the bigger numbers and i MUST have more  but the total there doesnt show more , , , grrr.
should i just buy some 2100s of some sort and BELIEVE? because not having them is killing me


----------



## NiOOH

VidPro.

If you ask for my opinion, I'd take the cell with lower internal resistance any time. Sheer capacity is not that important for me, especially when regulation is involved.
IMO Eneloop are excellent cells, even without the LSD, with it they are the best the market can offer in NiMH technology right now.


----------



## SilverFox

Hello VidPro,

It appears that, in spite of the labeling, the Eneloop cells have slightly higher Amp Hours and Watt Hours than the Hybrid cells. At low loads, the difference is small, but the gap widens at higher loads.

Tom


----------



## VidPro

SilverFox said:


> Hello VidPro,
> 
> It appears that, in spite of the labeling, the Eneloop cells have slightly higher Amp Hours and Watt Hours than the Hybrid cells. At low loads, the difference is small, but the gap widens at higher loads.
> 
> Tom


 
ohh i see that TOO, myself IF i was going to run some 4-6amps, i would probably use some larger battery or more of them. so to me the hard discharge tests show its general strength, but i wouldnt be using them that way.
the hybrids tested here fell down at the higher amperage even worse than the "normal" use of them.

so i dont need to buy hybrids untill something changes, that is good to know.


----------



## Kevin Tan

Would the Eneloops be a good candidate for the Mag85 with FM's 9AA holder? Will it flash the 1185 with the low internal resistance and hi voltage from low self discharge?


----------



## h2xblive

Kevin Tan said:


> Would the Eneloops be a good candidate for the Mag85 with FM's 9AA holder? Will it flash the 1185 with the low internal resistance and hi voltage from low self discharge?



I currently use Eneloops in a FM 9AA holder and a 1185 bulb in a 3D Mag. I've never turned on the light when the batteries were hot off the charger, but I have used them about 24 hours after being charged and no flashing so far.


----------



## h2xblive

LittleBrownStain said:


> Problem now solved, thanks to members *macdude22 *and *eebowler.
> 
> The Mag2D works perfectly with 2 AA eneloops sitting in 2 AA-To-D adaptors.* No, they won't last as long as 2 D cells, but then, I have a bucket-full of AAs, y'know?
> 
> So much for MagLite's warning not to use rechargeables.



The same applies to the Mag3D.

With the Mag LED drop in, I got over 6 hours of light, although the output was noticeably dimmer after about 4-4.5 hours.


----------



## SilverFox

Update:

I just got around to adding the data from 180 days of self discharge on the Hybrid cells.

Tom


----------



## Burgess

Thank you, Tom, for all of your great Battery info.


:bow: ___ :goodjob:

_


----------



## LuxLuthor

Kevin Tan said:


> Would the Eneloops be a good candidate for the Mag85 with FM's 9AA holder? Will it flash the 1185 with the low internal resistance and hi voltage from low self discharge?



Kevin, in large part it depends on how much resistance is in the mag setup you are using. IMHO, that is more related to whether the 1185 gets flashed than the internal resistance of the battery.


----------



## SilverFox

Update:

I just added test data from the Eneloop AAA cells.

Tom


----------



## LuxLuthor

Thanks again for all your testing results. I bet no one else has done so many different cells, so completely. I remember the only other shootout was one done years ago for cameras that had PowerEx at the top, but it was nothing like your work.


----------



## TorchBoy

Woohoo!


----------



## billw

Has anybody had their eneloops long enough to tell whether they still retain their charge as well after a couple-dozen use/recharge cycles? IIRC there were some primary battery "tricks" that made shelf-life of a totally unused battery much longer than that of one that had be used "a little bit", and I'm hoping there isn't some similar trick used to make the eneloops look good early in their life...


----------



## UnknownVT

Excuse me if this has been asked before -

In comparison - what is the typical self discharge rate of a primary Alkaline battery?

Thanks,


----------



## Anders

Sorry wrong post, could not delete.

Anders


----------



## SilverFox

Hello Vincent,

I believe Alkaline cells self discharge in the range of 2 - 5% per year at room temperature.

Tom


----------



## cave dave

I wonder how consistant the cells are. You are only testing two and averaging the results? I've noticed big variations in standard Nimh from cell to cell.

I just complete a second, 31 day self discharge test on eight Sanyo 900mAh *standard *Nimh (not eneloop).
The capacity remaining in each of the eight batteries:
1. 560 mah
2. 580 mah
3. 620 mah
4. 620 mah
5. 700 mah
6. 700 mah
7. 725 mah
8. 800 mah

The first test had similar results the top performers were always at the top and vice versa. 

The top performer had 43% more capacity than the bottom performer. If I could get a batch of top performers these would be great cells, and outperform eneloops if used in a month or two.


----------



## SilverFox

Hello Cave Dave,

The Eneloop cells start out very close. I have a standard deviation of 0.003 mAh on the initial tests of the 8 AAA cells that I have. At 30 days, the standard deviation was 0.000196 mAh, at 90 days it was 0.000491 mAh, and at 180 days it was 0.00275 mAh, which is close to what I started out with.

At the end of the self discharge study, I took the same cells and ran another capacity test. All 8 cells came in almost exactly as they did during the initial test. The standard deviation did increase, but it was marginal. It went from 0.003 to 0.003125 mAh.

Your cells are testing out very interesting... How close were they when you did an initial capacity check on them?

Tom


----------



## idiotekniQues

just ordered myself 24 of these puppies 

i hate the discharge of regular rechargeables, drives me nuts.


----------



## BlackDecker

idiotekniQues said:


> just ordered myself 24 of these puppies
> 
> i hate the discharge of regular rechargeables, drives me nuts.



Not sure where you are located but Circuit City stores are currently selling an 8AA pack of Sanyo Eneloop batteries for $14.96. Some here have noted that not all CC stores carry these batteries, so use their website to check for local store availability.


----------



## Burgess

Allow me to personally thank BlackDecker, once again,

for first bringing the Circuit City Eneloop sale to our attention. :twothumbs


Thank you ! :thumbsup:


:goodjob:
_


----------



## Handlobraesing

Can't wait to get test result on my samples.


----------



## Brlux

I just picked up 24 AA Eneloop cells from the Circuit City deal thanks. All of them had a date of August 2006 on them which I suppose is when they were last charged. I took the first 4 out of the packaging and threw them in my C9000 for a discharge capacity test. With a 500mA discharge they all were about 1336mAh which is about 67% of the stated capacity after 16 months. I am pleased with those numbers. I stocked up on the Hybrid cells a while ago and have been very pleased with them as well. I have a pack of the Hybrid cells hat has not been opened yet, I will open them and check their capacity. I can't say for sure how long they have been in the packaging but it is has probably been a year or so.

Edit: I did the Hybrid cells test. The 4 cells ranged between 1400-1450mAh not bad for siting in the packaging about a year.


----------



## How Goes It

I'm a newbie to this forum (first post).

Within a day or two, a couple Fenix L2D Cree Q5 flashlights should arrive at the house.

I've spent a little time looking at Candle Power, and figure the AA Eneloops would be good for my needs. I like what I've read of the slow discharge of the Eneloops. I've got a Circuit City close by that has them in stock.

The chargers I have came with a camera or some other electronic gadget I bought in the past. But none of these chargers are for AA batteries.

I've never bought a charger by itself. What's a good charger to use with these Eneloop batteries?

For what it's worth, I've also got some walkie talkies, a wireless VOX (voice activated) intercom system (which really eats primary alkalines), and a radio. All these items use AA batteries. Hopefully I could use the Eneloops in these things also.

Any help regarding what charger to use would be appreciated.

Thanks,
Steve


----------



## SilverFox

Hello Steve,

Welcome to CPF.

The battery manufacturers recommend two charging rates. 0.1C for 16 hours, or charging in the range of 0.5 - 1.0C with proper charge termination. You will get the best life from your cells by following their recommendations.

The Eneloop AA cells are 2000 mAh, so 0.1C = 200 mA, and the range of 0.5 - 1.0C = 1000 - 2000 mA. The Eneloop AAA cells are 800 mAh, so 0.1C = 80 mA, and the range of 0.5 - 1.0C = 400 - 800 mA.

If you only use cells of the same capacity, it is easier to pick a charger, however, if you have cells of a variety of capacities, you need a charger that allows you to set the charging rate.

Hobby chargers give you a lot of flexibility, but they are designed to work off of your vehicle battery. Bringing the charger inside usually requires the purchase of a power supply. Also, hobby chargers are more expensive.

The two consumer chargers that come up most often are the LaCrosse BC-900, and the Maha Wizard One C-9000. I use the C-9000, but before it came out I used the BC-900. You can do a search on both units here and in the reviews section to find information on these units. 

Tom


----------



## Codeman

SilverFox said:


> ...Someone else can do the 1 year testing…



Tom,

Has anyone posted any info yet on the Eneloops after a 1 year wait, un-used?

If not, I've got 12 that have been un-opened since I bought them 1/5/07, so I'll be happy to do C9000 discharge tests on them, if we don't already such data. 0.2C, right? I'll also get ZTS and V readings straight out of the package.

Assuming no one has done this yet, would you prefer that I post in this thread, or start a new one?


----------



## SilverFox

Hello Ray,

Go for it. Feel free to post the results here. I can add a link to your posted results in the first post so people don't have to wade through the whole thread to find it.

Tom


----------



## Mr Happy

Codeman said:


> Has anyone posted any info yet on the Eneloops after a 1 year wait, un-used?


I was interested in that too. See this thread:
https://www.candlepowerforums.com/threads/182369


----------



## Codeman

That sounds like a plan! :thumbsup:

I'll throw everything into a table when I'm finished.


----------



## DavidD

I don't have a charger that can discharge and check capacity, but one study I would like to see done is one that would simulate periodic use that non-flashaholics would likely engage in.

Typical use would be to start out with say, 6 fully charged batteries. Store them for a period of time, say 2 months. Discharge a certain percentage of capacity, say 400ma (is it 400ma or 400mah?) which would simulate using the flashlight. Store them for a period of time again (like throwing the light back in the utility drawer). After 2 more months (or whatever time), discharge 2 completely, checking for total remaining capacity. Discharge the other 4 batteries another 400ma(h), then store them for another period of time. Get them out after another 2 months, discharge 2 completely, checking for total remaining capacity. Drain off another 400ma(h), then store the last 2 for 2 more months and then discharge completely, checking for the total remaining capacity.

All of the self-discharge studies that I have seen on here are for long-term storage, then complete use. The idea here is to check self-discharge between periodic use. Seems to me that is how a lot of people use flashlights. Silly idea?

edit: This would also apply to camera use. Take a few pictures one day followed by a period of non-use. Take a few more pictures later, followed by a period of non-use. Repeat. Seems like it would be useful info to have.

David


----------



## Codeman

Here are the results of my 1+ year testing (19 months from manufacture, 12 from purchase):







where Projected 1 Yr Discharge = 2000 - ( ( (2000 - discharge) * 12 ) / 19 )

The date code on the packaging is 2006-05.

Assuming that the Eneloops have a reasonably linear self-discharge in the 12-19 month range and assuming a reasonable 5% error to take into account the accuracy of the C9000, this seems to confirm Sanyo's claim of 85% capacity remaining after 1 year.

I'm not sure what to make of the 80% readings from the ZTS meter, especially since I crossed checked them with a second MBT-1 and an MINI-MBT with no deviations. My guess would be that it's partly due to the tester's granularity (20% increments). Plus, the formula used for NiMH may not be ideal for Eneloops.

Regardless, this shows some impressive consistency, especially when cell #3 is ignored. Certainly far better than I've seen with any of my other NiMH AA cells. It should be interesting to see how well-matched they remain as they are used.

I've also run a refresh & analyze test on these cells, so that I'll have a baseline true capacity as I start to use them. 6 of them will go into immediate use while the remaining 6 will go into storage until needed.

Here's the refresh & analyze results:






Since cell #3 was middle of the pack on the R/A test, it appears that it may have simply had less initial charge from the factory.

I've completed a second discharge test.

The cells were discharged at 1A, then charged at 1.5A, including a 2 hour top off charge. The cells were then removed from the charger and allowed to rest for 30 minutes. I then did another 0.4A discharge test:






The 1,861 mAh average capacity from the second test is about 0.65% below the first test. :thinking:

02/05/2008 Update:

Here are the results of a Break In cycle (preceded by a 0.2C discharge):

Cell - Available Capacity
1 - 1938
2 - 1911
3 - 1923
4 - 1937
5 - 1913
6 - 1918
7 - 1930
8 - 1935
9 - 1926
A - 1929
B - 1911
C - 1944

Avg - 1926, Std Dev - 11


----------



## Brlux

What was the manufacture date stamped on the back paper? Mine were 2006-06 which is about 16 months ago and my cells tested nearly identical to yours?


----------



## Techjunkie

Tom,

Thanks so much for all the testing that goes into this thread. Do you have any numbers on the performance of the Duracell and Kodak precharged batteries at 5+ amps? I'm building a Mag61 and want the best LSD AAs for it. (Clearly the Eneloops outperform the Hybrids in this category based on your charts.)

Thanks!


----------



## Codeman

Whoops - I knew I'd forget something. Date code added to post #143. Thanks for asking, Brlux! :thumbsup:


----------



## Brlux

perhaps you should edit the header and other references in your test data and analysis to 19 month test instead of 1 year? It will make things clearer for others trying to understand your results. My cells all tested around 1330 +-20mah which makes sense, they are a few months newer but were discharged at 500ma.


----------



## Mr Happy

Codeman said:


> Assuming that the Eneloops have a linear self-discharge


Comments from Sanyo indicate that self-discharge is not linear; it is more rapid to begin with and slows down a lot once the cells have less than 80% charge. Also, the cells are apparently shipped new with a 75% charge, which would put the time zero point at about 1500 mAh.

From the post linked above, my cells with a 2006-08 date stamp averaged 1380 mAh when tested at the beginning of December. Your cells with a 2006-05 date averaged 1356 when tested a month later. At a rough estimate therefore, we may suppose a self-discharge of 25 mAh in 3-4 months, or 100 mAh per year. If your cells started out at 1500 mAh, then after 1.5 years that would put them at 1500 - 1.5 * 100 = 1350 mAh, quite close to what you measured.

The interesting question is whether this remarkably low self-discharge rate holds up after the cells have been cycled a few times as opposed to newly manufactured.


----------



## Codeman

Mr Happy said:


> Comments from Sanyo indicate that self-discharge is not linear; it is more rapid to begin with and slows down a lot once the cells have less than 80% charge....



For the purposes of extrapolating back to 1 year from 19 months, the early non-linearity doesn't come into play, except possibly as a small but indeterminate error. I've adjusted my earlier post to make what I meant a bit clearer. From the looks of the graph on page 5 of the Teraoka article, the self-discharge rate appears likely to be linear within the 12-19 month time frame.

It would be nice to get a hold of some Eneloops within 1 month of manufacture so that we could exactly what the initial charge is. Given Sanyo's claim of 10% in the first 6 months then 5% in the second six months, if another 5% is lost in the 3rd six months, then my numbers seem to imply an initial 90% charge (70% observed plus 20% loss). But is the remaining 10% due to a reduced initial charge, or simply the typical early behavior of NiMH cells? Until someone can get some very newly made cells, we may only be able to guess at the answer.


----------



## SilverFox

Hello Techjunkie,

Welcome to CPF.

I don't have samples of the Duracell and Kodak low self discharge rate cells, so I can't give you a comparison.

Tom


----------



## cave dave

I know that this has already been said, but people seem to miss that the cells aren't fully charged at the factory and that the decline isn't linear. Best to use a "Present Value" calculation to make estimates of self discharge rates. 

* EDIT*
So using data from the 30 day test from the first post of this thread I get a *self discharge rate of 0.25% per day*
Data from the 180 day test from the first post of this thread I get a *self discharge rate of 0.08% per day*

So the discharge rate is definitely going down.

My measurements for out of the box capacity on Aug2006 cells.
1: 1433 mAh
2: 1470 mAh
3: 1467 mAh
4: 1440 mAh


----------



## SilverFox

Hello Mr Happy,

The first post of this thread contains a graph that shows the different discharge rates for these cells. The data out to 180 days is measured from testing. The data beyond 180 days is projected using the 180 day results.

You can see a steeper self discharge rate at first, tapering off as time goes on.

Tom


----------



## SilverFox

Hello Ray,

I have added a link to your results to the first post.

Thanks.

Tom


----------



## Codeman

Thanks, Tom!


----------



## Codeman

Added refresh & analyze results to post #143.


----------



## SilverFox

Hello Ray,

I find it interesting that during the Refresh and Analyze, none of the cells came up to their minimum 1900 mAh.

I wonder if you would have time to run one more test?

Take a couple of cells and discharge them at 1 amp. Next charge at 1.5 amps and leave the cells on the charger for the 2 hour top off charge. Next, remove the cells from the charger and let them rest for around 30 minutes. Finally, run a discharge at 0.4 amps to see if they break the 1900 mAh capacity.

I am trying to remember if Refresh and Analyze uses the top off charge...

Tom


----------



## Codeman

I don't think it uses top off, but that's a guess. When I started the R/A test, the cells were charged and rested for 24 hours, so the initial charge only last a minute or so before the rest cycle started - surely they don't do a topoff when it says resting. To be honest, I hardly ever think about the topoff. I usually pull cells when it shows done. I know that means they aren't fully charged, but I prefer cycle life for most purposes. Which is why I didn't question the numbers myself. They seem reasonable, if I'm right about there not being a top off during the R/A test.

It makes sense to include a top off for this thread, though. Given the times and my normal sleep/work schedule, I'll have to wait until this weekend.

EDIT:

Well, the way the manual describes it (last page, under #9), I believe a top off is applied, but only at the very end of the R/A mode:



> When the program for a slot is completed, DONE will displayed to
> the right of the bank number. With the exception of DISCHARGE
> mode, topoff charge and trickle charge (continuous) will be applied.
> For CHARGE mode, the total charged capacity will be displayed.
> For REFRESH & ANALYZE, BREAK-IN, DISCHARGE mode, the
> total discharge capacity will be displayed. “AVAILABLE CAPACITY”
> icon will also be shown.


----------



## Ayeaux

I Thought I'd add my own experience with some newly bought eneloops from cc dated 08/2006. I discharged them straight out of the package at 350 ma.


----------



## BentHeadTX

I have tested 15 Eneloop AA batteries with a date of 09-2006 on the package. They all register 65 to 70% one either a Cadex C7400ER wazoo battery analyzer or my Maha C9000. This testing was performed Dec 2007 or January 2008 so I knight the Eneloops as the battery to have. 

PS All my Powerex 2700 AA NiMH cells are getting to end of life. They don't like a Fenix L2D CE or RB100 running on turbo every day without dropping serious voltage. Eneloops have a much better voltage curve.


----------



## moldyoldy

Post removed per request


----------



## Codeman

moldyoldy said:


> With most of the input in this thread regarding Eneloops, here is an input for Maha Imedion cells.
> ...



Since this thread is about Eneloops, maybe you should post your info in a new thread so that this one can stay on topic.:thinking:


----------



## SilverFox

Update:

I placed some Eneloop cells in a CD player I have. It does not have a clock. When it is shut off, the display is blank.

I just tried to play a CD in it after 6 months of storage and found the batteries completely discharged.

I expect there may be a slight parasitic drain, but I have been unable to measure it. At any rate, if you are using these low self discharge cells in devices that get infrequent use, I would recommend that you check on them, from time to time, to make sure something similar isn't going on.

I am now storing the batteries separate from the player and not installed.

Tom


----------



## Burgess

Interesting . . . .


I learned the hard way that my *Brand-New*

(now 13 years old!) Sony WM-FX52 Walkman

draws 20mA of current, in order to maintain the User-Selected-Presets.

This was enough to completely Drain my Alkaline AA's in less than a week !


Then i'd hafta' go through the hassle of re-programing my favorite stations *all over again*. :hairpull:


After a few weeks of this, i gave up storing batteries in this device. :thumbsdow

_


----------



## Codeman

I've started the new discharge tests per Tom's request. Just to satisfy my own interest, I'm going to run it on all 12 cells. Hopefully, I'll have the results tomorrow night or Monday.


----------



## radellaf

Burgess said:


> Interesting . . . .
> WM-FX52 Walkman...20mA of current, in order to maintain the User-Selected-Presets.[/SIZE]



Yeah. Had one of those. Never measured, but sure learned to fugeddabout my presets since it killed batteries in a hurry.


----------



## Codeman

Tom,

Once I get home today, I'll post the results of the second discharge test, but the results weren't good. The average capacity was 1861 mAh, about 0.65% less than the first discharge test. Even more troubling was an average self-discharge of 8.67% that occurred between the two tests (6 days).

Unless Eneloops need a break-in when they've been stored for 1+ year, I'm at a bit of loss...


----------



## Mr Happy

Codeman said:


> Once I get home today, I'll post the results of the second discharge test, but the results weren't good. The average capacity was 1861 mAh, about 0.65% less than the first discharge test. Even more troubling was an average self-discharge of 8.67% that occurred between the two tests (6 days).


Lately I've been measuring about that capacity (1850 mAh) on my Eneloops. Regarding the self-discharge, I think Eneloops share the same characteristic with traditional NiMH cells of high self-discharge in the first few days or weeks after charging. It's after a month or two that the self-discharge really slows down to a low rate.


----------



## Codeman

The later slowdown has no bearing on an extremely fast 8+% drop in 6 days, though.

Tom, doesn't Sanyo claim something like 5% in the first 90 or 180 days?

I've added the results of the second discharge test to post 143.


----------



## robm

Codeman - can you explain which figures/tests you are comparing to get the 8% self-discharge?

It looks (to me) as if the test after 6 days was done using a discharge rate of 1A, whereas all the other discharges were at 400mA?
Capacity does drop with higher discharge - could this be cause of the apparent drop in capacity?


----------



## Codeman

Well, duh! 

robm, you're exactly right. Thanks for figuring it out!

One of the fun things about getting older - knowing something, but not remembering it when needed!


----------



## robm

Here to help 

8% does seem quite a big difference though.

You do realize that you now have to repeat this test, but choose the 400mA discharge?
It is only fair:nana:


----------



## Codeman

robm said:


> Here to help
> 
> 8% does seem quite a big difference though.
> 
> You do realize that you now have to repeat this test, but choose the 400mA discharge :nana:



Already did (see the last column)!  :nana:

Actually, I'm tempted to try a break-in cycle to see if that will get them up to 1900 mAh. But I want to see what SilverFox thinks about this second discharge test before I spend that much time on them.


----------



## SilverFox

Hello Ray,

:devil: It is my humble opinion... that if you aren't using them, test them to death!!! :devil:

With that said...

Let's see now, you got 1871 mAh, on average, with the Refresh and Analyze, and 1861 mAh, on average, with the charge, rest, then discharge. I think the 10 mAh difference can be explained by the way the Refresh and Analyze is done, but it looks pretty close to me.

Let's see if my math works, 1861 is about 99% of 1871. Now, if we compare that to the 1900 mAh minimum, we are down a little. If you ran a Break-In cycle, you would probably bounce back over the 1900 mAh mark.

I think you should do a Discharge then Break-In cycle every year anyway, so, if you have the time, give it a go.

Tom


----------



## Codeman

Well, in the interest of science...I can probably get 4 of them done a weekend.

Too bad the testing didn't give a clear indication as to whether a top off is done during the refresh/analyze cycle.

How much testing do I need to do to become SilverFox, Jr.?


----------



## Mr Happy

Codeman said:


> Too bad the testing didn't give a clear indication as to whether a top off is done during the refresh/analyze cycle.


From a design perspective, I would think the answer ought to be that it does do a top off. The objective after all is to analyze the full capacity of the cell, and without a top off it won't be fully charged before the discharge measurement is done. Also there is, I think, a two hour interval between charge and discharge that would be just the right length of time for a two hour top off charge.

In one of my own tests recently (see the MQN05 thread), I found that Eneloops measured immediately after the C-9000 says done only contained 1700 or so mAh. If refresh/analyze shows more than this it is likely to be including a top off charge.


----------



## Bones

Codeman said:


> Well, in the interest of science...I can probably get 4 of them done a weekend.



Is there a reason you're waiting for the weekend Codeman?

The BC-900-v32 melt down posts were among the first I read on this forum.

Out of an abundance of caution, I decided to set up my MH-C9000 charger inside an old metal pan in case it had the same tendancy.

Knowing that even if things go awry, there was now very little likelihood of a catastrophic consequence, I quickly got into the habit of setting and forgetting the charger in the modes that don't require it to terminate on a signal.

I especially monitor the processes that require it terminate on a signal because I have a first edition, and if it misses a signal, it could conceivably pump 20,000mAh into the cell before it times out.

This hasn't been a burden simply because I prefer to utilize my plug 'n play Eneloop MQN05 for all my basic charging.

Anyway, there have since been times when I haven't gotten back to the charger for several days after a process has ended, such as a discharge or break-in cycle, and it doesn't seem to have had any ill effect on either the cells or the charger.

As long as it doesn't lose power, the charger also seems capable of maintaining the process results in memory for a indefinite period.

For what it's worth...


----------



## Codeman

I just got off the phone with Maha tech support. There is no charge of any type applied during the rest stage of any mode. Topoff/trickle charging ONLY occurs when the C9000 displays "done", except at the end of discharge mode, when no charge is done. The manual agrees with what I was told.


----------



## Brooke

Hi:

Before I found this thread I started my own analysis of the eneloops. The first step was determining the capacity each cell. I've got a bunch of chargers (see: http://www.prc68.com/I/BatChg.shtml). Started with the C777Plus but it has a problems and traded it in for the C777Plus2, but in the mean time got the C9000 and C401FS. The C9000 results were not consistant and so changed to using the C401FS for charge and the C9000 for discharge. This combination provides less than 1% repeatability, see:
http://www.prc68.com/I/RTU-Batt.shtml#PCT)

Reading the white papers at Sanyo and Duracel shows that neither of them recomend negative delta V/delta t as a charge termination method.

I'm testing 4 each aa Ni-MH: eneloop 2000, Maha Powerex 2700, Kodak 1600 and made in china green wrap 1800 Ni-Cad. The idea is to compare the eneloop with older chemistries.

The interesting thing is the Powerex 2700 appears to be a long shelf life type although it's not advertized that way. See:
http://www.prc68.com/I/RTU-Batt.shtml#TRT

PS. Is there a source for replacement "D" size cap springs for old Flash Lights, see: http://www.prc68.com/I/FlashlightPat.shtml#ER2697

PPS. Is there a thread about Flash Amps? Is there a tester? I've started rounding up parts to make a tester and learning how to measure the 10 milli ohm load.


----------



## SilverFox

Hello Brooke,

I find it interesting that you are having problems with the C9000. I wonder if you could share the method you use for charging with it. There are some "quirks" in using it, but once you get your protocol down, it seems to do a pretty consistent job of charging.

I would love to see Sanyo, Duracell, or anyone else come out with a consumer charger that follows the battery manufacturers recommendations for charging. The hobby chargers come close, but most of them also utilize -dV for termination. I believe the general public places too much value on initial cost to go for a more expensive, but better for your cells type charger.

You will also note that the battery manufacturers recommend fast charging with proper termination. One of the methods mentioned is -dV, but the recommendation is that you have to use a lower value than what was used for NiCd cells. Duracell goes on to recommend 5 - 10 mV as acceptable -dV values. They also go on to point out that using temperature, temperature slope, voltage, or drop in voltage for termination, you should be charging in the range of 0.5 - 1.0C. It is also interesting to note that a lot of the data they provide is obtained using 1C charge rates.

The other generally accepted charge rate is the 0.1C for 16 hours. Obviously this is timer controlled, with maximum temperature as a back up. Duracell tries to wimp out by suggesting 12 hours, but the revert back to the industry standard 16 hours when rating their cells for capacity and cycle life. 

The people checking flash amps have been using the leads from their voltmeters as resistors and simply reading the value on the amp scale of their voltmeter. I think the voltage response to a load is valuable, but am not sure how much flash amps tells you about the cells ability to perform other than in a nearly dead short condition. Most of our applications operate at less than 10 - 20 amps, so the flash amp load seems a little high.

On the other hand, a loaded voltmeter reading should give you results similar to the ZTS tester, once you develop your voltage reference database.

Tom


----------



## generic808

I just picked up the battery/charger combo from a local Costco and was wondering how I should start using them? Is there a break-in period, or anything that I should know of prior to using them? I want to get the most out of these batteries, so please do enlighten :candle:


----------



## SilverFox

Hello Generic,

In general, you can just use them. Limit your discharges to less than 100% and don't leave them to cook in the charger. When the charge has completed, remove the cells from the charger.

Tom


----------



## Codeman

SilverFox said:


> Hello Ray,
> 
> :devil: It is my humble opinion... that if you aren't using them, test them to death!!! :devil:
> 
> With that said...
> 
> Let's see now, you got 1871 mAh, on average, with the Refresh and Analyze, and 1861 mAh, on average, with the charge, rest, then discharge. I think the 10 mAh difference can be explained by the way the Refresh and Analyze is done, but it looks pretty close to me.
> 
> Let's see if my math works, 1861 is about 99% of 1871. Now, if we compare that to the 1900 mAh minimum, we are down a little. If you ran a Break-In cycle, you would probably bounce back over the 1900 mAh mark.
> 
> I think you should do a Discharge then Break-In cycle every year anyway, so, if you have the time, give it a go.
> 
> Tom



I've added the Break-In data to post 143.

The average was 1926 with a std dev of 11. Given such a low std dev, I wonder if it's even worth it to match these cells up?

On a side note, since all cells had been topped off prior to this latest test, I recorded the initial 0.2C discharge numbers before the break-in for cells 5-C (I forgot to write them down for cells 1-4). After a 2 week rest, cells 5-8 averaged 1703. After 3 weeks, cells 9-C averaged 1698. It would seem any advantage to doing a top-off charge is lost within the first couple of weeks, unless a break-in charge has an impact. :thinking:


----------



## Brooke

Hi:

When I started testing four different brands of AA cells using the C9000 for both charge and discharge I was not able to get consistant results, see the table entries starting with Note 1. But when using the C401FS for charge and the C9000 for discharge the results were very consistant, see data from Note 4. http://www.prc68.com/I/RTU-Batt.shtml#PCT.

My C9000 has a sticker number OGODO1. Is it out of date?

The interesting cells are the Maha Powerex 2700. Although their discharge rate is very slightly higher than the eneloops (I think they are eneloops) the capacity is considerably higher so far (at 4 and 8 weeks). Test still in progress.

Have Fun,

Brooke


----------



## Mr Happy

What is your charging method using the C9000? With newer high quality varieties of cell, charging has not fully completed at the moment that Done appears (*). To obtain a full charge, you should wait until Done and then leave the cells on the charger for another 2 hours. This process should give you more consistent results. 

(*) The reason is that newer cell designs have higher voltages and tend to reach the high voltage cut-off on the C9000 before the -dV signal is detected. This leaves them a little short of a full charge and needs the top-off charge to finish them off.


----------



## SilverFox

Hello Brooke,

Your results seem to be counter to everyone else's with the Eneloop cells. Everyone else comes up with over 1900 mAh on the break in, and you are down a lot from that. I have some trashed Eneloop cells that perform better than your cells are indicating.

You should note Ray's results in post 143 for his break in values. He came up with an average of 1926 mAh over 12 different cells and a standard deviation of 11 mAh. I think that is a pretty tight group.

Why are your results so far off?

Tom


----------



## Mr Happy

Actually Brooke, that whole web page looks very confusing to me. I can't easily tell what cells are being tested and what tests are being performed.

For instance, what are the Kodak cells? I can't find any description or picture of what they are. You say the label capacity is 1600 mAh but that seems quite low. The Kodak Pre-Charged for instance, have a label capacity of 2100 mAh.

Also, there is a reference to Powerizer (sic) Immedion 2100 mAh cells, but I don't see reference to 2100 mAh cells in the tables. (The Immedion brand by Maha is Powerex, rather than Powerizer. Maybe it's a typo?)

What are the "China" 1800 mAh cells? I can't really find a description of those either.

As Tom (SilverFox) says, your capacities for the Eneloops on the break-in cycle are extremely low. You should be seeing around 1900, 1850 at the lowest.

Overall, I'm sorry to say I just don't get a good understanding of what you are testing and how you are doing the tests.


----------



## TorchBoy

FYI the last six Eneloop break ins I did got 2061, 2072, 2067, 2059, 2086, 2067 mAh.


----------



## Brooke

Hi:

Sorry about the confusion on what's being tested. 
1) New AA eneloop Ready-To-Use long shelf life Ni-MH cells (2000 mAh)
2) New AA Powerex (yes it was a typo) (2700 mAh)
3) Old AA Kodak standard Ni0-MH a few years old from my camera (1600mAh)
4) Old AA Battery Space "made in China" Ni-Cad (1800 mAh).

I spent a few weeks with the C9000 just charging and discharging the same cells over and over to see how repeatable the results would be (needed info to do the shelf life tests) and they were poor. 
http://www.prc68.com/I/RTU-Batt.shtml#PCT

After moving the charging to the C401FS the repeatability is considerably better than 1%.

Have Fun,

Brooke
http://www.prc68.com/I/FlashlightPat.shtml


----------



## SilverFox

Hello Brooke,

Thank you for the clarification on the cell types.

I think I may have finally figured out what is going on. It would appear that you pulled the cells on the C9000 before the top off charge had completed. This will give you inconsistent results because the charge time is different for each cell.

Looking further at your data, it also is beginning to make sense. You are showing results that are around 4.5% lower than what others are getting. In looking up the 401 charger performance, I noticed that it under charges, when compared to the C9000, by about the same amount.

It appears that your cells are OK after all. The problem is either with your C9000 or your procedure used for charging.

Tom


----------



## SilverFox

Update:

Cannesahs sent me some GP ReCyko AA cells to check out. Thanks Jyrki.

These cells are not labeled as to their capacity, so I guessed at 2050 mAh.

The initial testing of the cells is up in the first post. It will be interesting to see how well they hold their charge over time.

Tom


----------



## Anders

Hello Tom.

The GP ReCyko AA cells had much to deliver and also could handle high amperage, like the Eneloops.

You have some LSD cells now, have you weight them or checked the length or thickness?

Some says that it is only two or three manufacturers on LSD cells, maybe the difference will tell us that it is more manufacturers?

" Sanyo made -

eneloop - 2000mAh, 1,000 cycles

Others - (only made by Yuasa?) -

RoV Hybrid - 2100mAh, more than 500 cycles
Uniross Hybrio - 2100mAh, 500 cycles

Panasonic R2 - 2050mAh, 1,000 cycles
Kodak Pre-Charged - 2100mAh, 1,000 cycles"
https://www.candlepowerforums.com/threads/147935&page=5


Anders


----------



## shadowjk

No capacity marking? My recyko cells have the following text:



Code:


GP ReCyko+
GREEN GENERATION BATTERY TECHNOLOGY

Rechargeable NiMH AA HR6 2100ACHB TYP.2050mAh 1.2V
Standard Charge: 16Hrs at 200mA
Caution: Observe polarity. Do not incinerate,
disassemble or short circuit. Made in China

"GP" is a registered trademark and
"ReCyko" is a trademark of Gold Peak Group.

GPIM

USE 1000 TIMES - ALWAYS READY

www.gprecyko.com
Product of Gold Peak Group

Phew, that's alot of text on a battery... The "GPIM" is barely readable, it's stamped/embossed into the wrapper. Do I have a different batch/kind of ReCyko when mine have typ. capacity, 2050, printed on them?


----------



## Handlobraesing

SilverFox said:


> Update:
> 
> Cannesahs sent me some GP ReCyko AA cells to check out. Thanks Jyrki.
> 
> These cells are not labeled as to their capacity, so I guessed at 2050 mAh.
> 
> The initial testing of the cells is up in the first post. It will be interesting to see how well they hold their charge over time.
> 
> Tom



Any interesting update from my samples?


----------



## SilverFox

Hello Shadowjk,

OK, I found it. My cells say the same thing as yours do. I am not sure how I missed that, must have set my magnifying glass aside...

Tom


----------



## SilverFox

Hello Handlobraesing,

Your cells still have good capacity, but they have increased internal resistance, and seem to have lost their low self discharge capabilities.

I am not sure how many cycles you had on them, but I have put an additional 50 or so.

Tom


----------



## shadowjk

btw, Impressive guess that they're 2050


----------



## SilverFox

Hello Shadowjk,

 It comes from running lots and lots of tests on batteries...

Tom


----------



## TorchBoy

Anders said:


> The GP ReCyko AA cells had much to deliver and also could handle high amperage, like the Eneloops.
> ...
> Some says that it is only two or three manufacturers on LSD cells, maybe the difference will tell us that it is more manufacturers?
> 
> " Sanyo made -
> 
> eneloop - 2000mAh, 1,000 cycles
> 
> Others - (only made by Yuasa?) -
> 
> RoV Hybrid - 2100mAh, more than 500 cycles
> Uniross Hybrio - 2100mAh, 500 cycles
> 
> Panasonic R2 - 2050mAh, 1,000 cycles
> Kodak Pre-Charged - 2100mAh, 1,000 cycles"
> https://www.candlepowerforums.com/threads/147935&page=5
> 
> 
> Anders



Anders, do you know who makes the Maha Imedion? Are Duracell and GP ReCyko made by Sanyo?

And Mr Happy's tests imply his Uniross Hybrios are relabeled Eneloops that claim to be made in China.


----------



## Anders

Hello TorchBoy.

No, sorry I haven't got a clue, I wonder if we ever get to knew who made what, it seems to be a closely-guarded secret.

I'll try to ask MAHA here in sweden, but I don't think they know, and if they know that another manufacturer make them, I don't think they will answer.


Anders


----------



## Mr Happy

Take a look at the physical appearance of the cell underneath the label. That gives a big clue.

Broadly speaking, Eneloop clones seem to have a white top, a squarish button with four small vent holes at the "corners", no vent holes in the white plastic seal, and a distinctive ridge shape at the negative end. In my explorations, Eneloop clones include Duracell Pre-Charged when made in Japan, Sony CycleEnergy pre-charged, and Uniross Hybrios.

The other kind of cell (Yuasa-Delta?) has a black top with four vent holes in the plastic, a rounder button, a slightly larger diameter, and a differently shaped ridge at the negative end. This kind seems to include the Rayovac Hybrid, the Kodak Pre-Charged and the Duracell Pre-Charged when made in China.


----------



## Anders

Hello Mr Happy.

I just asked Maha here in sweden by mail.

It seems that Maha Imedion have most capacity than everybody else according to several tests, not only mine, do you think they are made from another manufacturer than Sanyo or Yuasa-Delta?

I haven't yet looked closer to my Imedion cells.

Anders


----------



## TorchBoy

This photo shows them to have a white top and rounded nipple (button?). A mix of the features? I can't see any vent holes there.

Who makes Maha's other cells? The article that picture illustrates implies they make their own.



> Founded in 1993, Maha Energy Corporation designs, manufactures and markets batteries and chargers under one roof.


----------



## Mr Happy

Anders,

I don't know, but I suspect the formulation of these LSD cells can be tweaked to give slightly different properties. After all, we show no surprise when traditional NiMH cells are made in capacities of 1600, 2000, 2300, 2700, etc.

For example my tests indicate that the Hybrios may have a marginally greater capacity than true Eneloops, even though they are otherwise very similar in every respect.

If a company is able to commit to a large enough production run from the factory for resale under their own label, they may be able to request adjustments to the formulation to suit their own requirements.

This is just speculation, but I don't see why it couldn't happen that way. On the other hand, there is a lot of variation possible between samples, and between test protocols, and so some of the "differences" reported may be illusory.


----------



## Mr Happy

Ian,

Many parts of that article suggest Eneloop technology to me. For instance "85% after 1 year", "low impedance design", "2100 mAh" (c.f. Hybrios), "$13.95 for 4". The only thing that doesn't quite match is the rounded top and smaller button, but it is hard to see exactly what the metal button looks like from that photo. If I had to go out on a limb I'd say they licensed Eneloop technology or they are buying from an Eneloop factory.


----------



## TorchBoy

I like your idea of tweaking the formula, Mr Happy, although from the third graph (Eneloop vs Imedion) in Anders' analysis, I'm not convinced. To me those discharge curves look quite different.


----------



## Mr Happy

TorchBoy said:


> To me those discharge curves look quite different.


They do look different, don't they? However, the black curve -- the Eneloop at 0.4 A discharge -- seems to hit 0.9 V at less than 1800 mAh capacity. That doesn't quite ring true, since fully charged Eneloops can easily exceed 1900 mAh on a 0.4 A discharge test. Some get as high as 1980 mAh.

I think this shows the dangers of this kind of comparison. I'm not saying you are wrong about Immedions being different, mind; the Immedions may indeed be different from Eneloops, but when comparing cells it is hard to be sure about results unless everything is as similar as possible during every part of the test. 

Preferably one should also take a group of cells of each kind and average the results before comparison. In my Hybrio tests I have had two cells under examination, and they are not identical. One consistently has a higher capacity than the other in each test.


----------



## SilverFox

Update:

I have a Mag85 that I use a set of 9 Eneloop cells in. A year ago, I charge that set up and set it aside. After 1 year, they had 1578 mAh under a 1 amp discharge load. Initially, they had 1871 mAh, so it seems they fell short of their advertised 85% retention after a year.

However, 84.34% is pretty close...

Tom


----------



## TorchBoy

Tom, even 1871 mAh seems quite low, but I think the claim is "up to 85%".  What temperature were they stored at?

Mr Happy, yes, much of those results are at least a little suspect. I guess I don't have any evidence to think they're different, so I look forward to some more tests.


----------



## SilverFox

Hello Ian,

Keep in mind that this is for a 1 amp rate. The were stored at room temperature.

Tom


----------



## Anders

Hello TorchBoy.

You earlier pointed at my Earlier thread "Imedion Study"
In that thread my first information on the Eneloops and the VS graph was wrong, I wrote later that my initial testings on Eneloop wasn't right. (post11)

----------------------------------------------------------------------------------------
"Update.

In my first post I had a Eneloop graph with an old result, I now did another one with same test conditions as with the other tests, the results is almost the same as Silverfox thread on Eneloops:"
https://www.candlepowerforums.com/posts/2282730&postcount=11
----------------------------------------------------------------------------------------

Unfortunately didn't I change the graph with Eneloop VS Imedion because I didn't want to change it because it is hard to understand if some posts was changed. I now did an update in that post, sorry.

Here is a better graph with cells charged and discharged with the same conditions: (2100 mAh for Imedion is right)







As you can see, there is not much difference between them both.

I am sorry if I wasn't clear enough.

Anders


----------



## UnknownVT

Mr Happy said:


> The only thing that doesn't quite match is the rounded top and smaller button, but it is hard to see exactly what the metal button looks like from that photo.


 
Using http://images.google.com/ I looked for photos of the Maha Imedion (and other LSDs). 

google Image search on Imedion

google Image search on eneloop

google Image search on Hybrio

The photo TorchBoy linked to is probably the best currently on the web of the Imedion - many of the others were merely the same photo scaled down.

Here's a quick photo comparison -

Thew biggest and best photo on the web of the Imedion that TorchBoy linked to (many others are basically this photo sized down)






Another that's not based on that photo -





Compared to the eneloop -




the significance of this is there are 8 eneloops in this photo and one can see that at almost any orientation one can easily see those vent holes on the +ve button - 

Some photos of the Uniross Hybrios -







Again those vent holes on the button are easily seen on these photos (even on that smaller and much poorer photo) - 

Which means if the Imedion photos are real (and not an artist's rendition) -
one should be able to easily see similar vent holes if they had them.

However Anders actually has some Imedions - 
can you please tell us if the +ve button has those eneloop-like vent holes?

Thanks,


----------



## Anders

Hello Vincent.

No vent holes on Imedion:




Same length and width as Eneloops.
Anders


----------



## TorchBoy

Thanks for that clarification Anders, I did get a bit confused by that funny Eneloop result - I obviously wasn't paying enough attention. The curves now look very similar, although if that difference in capacity is significant I'm not sure it can be used to support any claim that they're the same battery. Maybe composition-tweaked, but I found a mention on Maha's site that they make their stuff in Taiwan. I don't know if that applies to their batteries as well.


----------



## UnknownVT

TorchBoy said:


> but I found a mention on Maha's site that they make their stuff in Taiwan. I don't know if that applies to their batteries as well.



So let's ask the obvious question where are they made on the battery label, and does the packaging say the same, Anders again, please?

Thanks,


----------



## Power Me Up

UnknownVT said:


> So let's ask the obvious question where are they made on the battery label, and does the packaging say the same, Anders again, please?



I've got some Imedion in AA & AAA and they both say Made in Taiwan on the label...


----------



## UnknownVT

Power Me Up said:


> I've got some Imedion in AA & AAA and they both say Made in Taiwan on the label...



Thank you very much for that.

So conclusively (sorry for stating the obvious) we must now have at least 3 factories for LSDs - 
Sanyo in Japan,
Yuasa in China,
?? - in Taiwan


----------



## Yorkshire Pudding

Might not be as straightforward as we assume. Do the battery manufacturers design and build their own manufacturing machinery, in which case a particular design will be peculiar to that manufacturer, or are there third party companies who supply their design of equipment to various manufacturers?

John L


----------



## Rzr800

SilverFox said:


> "..note Ray's results in post 143 for his break in values. He came up with an average of 1926 mAh over 12 different cells and a standard deviation of 11 mAh...Tom"


 
Not that it is news to anybody....but my results were pretty much identical to Ray's (estimated; didn't write them down) on approx. 30 AA Eneloops that I broke in on the C-9000.


----------



## Anders

Differences between Eneloop vs Imedion.

Imedion cells are heavier than Eneloops, not much but measurable.


Imedion
434,4 grain, 28.15 grams
431,5 grain, 27.96 grams
431 grain, 27.93 grams
429,3 grain, 27.82 grams

Eneloop
406,5 grain 26.34 grams
406,5 grain 26.34 grams
405,6 grain 26.28 grams
405 grain 26.24 grams



Eneloops is more even in weight.

I think, usually more weight is the same as more mAh?

Thoughts?

Anders


----------



## Mr Happy

Interesting weight data there.

I think, taking all things together, that the Immedions may be similar to Eneloops in some ways, but they are not similar enough to conclude that they are made with the same Sanyo technology.

In this thread I weighed some different cells and the Duracell 1700 were heavier than Eneloops even though having a similar capacity. So there isn't a certain correlation between weight and capacity in every case it seems.


----------



## UnknownVT

SilverFox said:


> I placed some Eneloop cells in a CD player I have. It does not have a clock. When it is shut off, the display is blank.
> I just tried to play a CD in it after 6 months of storage and found the batteries completely discharged.
> I am now storing the batteries separate from the player and not installed.


 
Ha-ha! this has just happened to me.....

I bought a second MP3 player about 3.5 months ago with better capacity and longer playing time than the first one I had (both use a single AAA).

So about that time I used the second one much more, to the point where I just put an eneloop AAA in to the first to keep it "ready" - today I tried to play the first MP3 player, and I was dismayed to find it would not power on - changing the battery - it worked - so I checked the voltage of the eneloop AAA - down to about 0.55Volts - ouch! - it's on charge now, and I have noted its number - hopefully it is not badly damaged.

Although this could possibily have damaged the eneloop - think what may have happened if I kept an alkaline in it (which I was tempted to do ) it probably would have leaked and damaged the player.......

Like you - I am now going to keep that MP3 player "unloaded" until I need to use it.......


----------



## Mike86

I found this forum while trying to find information on eneloop batteries. Specifically why the instructions state not to plug the charger in upside down or it will finish charging before it is fully charged. I’ve never heard of such a thing & did email Sanyo several times asking why. I finally received a reply stating:

“The batteries contain electrolytes in liquid form. If they are charged any other way than upright, it is possible that you will not get a 100% charge every time. No damage will be done to the batteries, only the fact that you could possibly find yourself charging them more than what is necessary...which, in turn, will decrease the overall life of the cells.”

While waiting for their reply, I previously thought I saw something about possible electrolyte pooling in another thread, but can’t locate it at the moment. I’m curious if anyone has found any difference in the charging position of the batteries. IOW, is this really critical in charging the cells to their maximum capacity? Are the forum members here actually keeping the batteries upright when charging? Or is Sanyo just being too critical? Is the eneloop electrolyte any more “liquidy” than other NiMH’s electrolyte? Since my wall outlets are sideways I have used an extension cord in order to keep the charger positioned upright.

Obviously I want maximum capacity, but am I being too concerned about nothing?


----------



## TorchBoy

:welcome: Mike86.



Mike86 said:


> “The batteries contain electrolytes in liquid form. If they are charged any other way than upright, it is possible that you will not get a 100% charge every time. ...”


My crapometer has just been triggered.

I'd be more inclined to believe a heat-related explanation.


----------



## SilverFox

Hello Mike,

Welcome to CPF.

You may find this thread informative.

Tom


----------



## LuxLuthor

TorchBoy said:


> :welcome: Mike86.
> 
> 
> * My crapometer has just been triggered.*



Link added


----------



## Bones

TorchBoy said:


> :welcome: Mike86.
> 
> My crapometer has just been triggered.
> 
> 
> 
> LuxLuthor said:
> 
> 
> 
> Link added
Click to expand...


One of our crapometers must need recalibration, mine is pegging right off the scale at the nonsensical response that Mike86 received from Sanyo's representative.

Must have graduated very near the top of his/her creative writing class ...


----------



## TorchBoy

LuxLuthor said:


> Link added


:laughing: Brilliant. I've bookmarked it for future reference.


----------



## Mike86

Thanks for all the replies.

I never heard of battery position affecting charging capacity. When the NC-MQN05U instructions mentioned this I became curious & went to the Sanyo eneloop web site. They did not list this charger, but had 2 others and both of those instructions said the same thing about not charging upside down. So I started searching for answers & emailed Sanyo several times & finally got a response.

Just for the heck of it I should ask Sanyo if capacity is also reduced if used upside down!

If buying the eneloop cells by themselves is there any mention in the packaging regarding the charging position? Another thread mentioned the MQN06 had a temp sensor at the bottom. Perhaps the MQN05 also has one at the bottom & the upright charging "caution" is really about the charger & not about the batteries. 

Curious Mike


----------



## Black Rose

My NC-MDR02N Eneloop charger also says not to plug in upside down, or it may finish charging before the cells are fully charged.

The packaging for the 2 pack and 4 pack of Eneloops I purchased make no mention of the charging position.


----------



## Mike86

Your crapometer is going to break now.

I just had to contact Sanyo again. I asked about the electrolyte, about discharging upside down, and about the separately packaged eneloops that made no mention of charging right side up. Here is their response:


The batteries your friend bought wouldn't have the
instruction to position the charger upright because he
bought the batteries separately. It still implies to when he
charges his batteries in another charger. I do not know
about other brand of chargers, but it is likely they all say
the same thing on their instructions about the batteries not
fully charging to their full potential. In regards to your
camera, it will not do any harm or discharge them
differently to the batteries because they aren't charging in
your camera.

Best Regards,

Customer Service
Sanyo Energy (U.S.A.) Corp.
http://www.eneloop.com
http;//www.sanyobatteries.com


----------



## 45/70

Looks like, possibly...... just possibly, there may be a job opening at Sanyo USA's customer service department..... soon! 

Dave


----------



## Bones

Mike86 said:


> Your crapometer is going to break now.
> ...



If the cells should to be upright to charge, then wouldn't the same thing apply when they are discharged?

Perhaps you will find that your camera will take fewer shots when repeatedly used in positions other than upright.

Or would the opposite apply, and the cells should be positioned upside down when being 'drained' of their energy?

I'm so confused ...


----------



## Mr Happy

If you examine a rechargeable battery carefully, you will notice little vent holes around the top near the button.

When you charge the battery you must keep it upright or some of the charge will escape out of these vent holes and get lost.

This doesn't matter so much when the battery is being used after charging, because by that point the charge has been soaked up in the electrolyte like a sponge and it can't escape so easily.


----------



## 45/70

Correct me if I'm wrong Mr H, but I believe if the vent holes actually "vent", you loose electrolyte regardless of the cells position.

As far as why the instructions say to keep the charger upright? As someone has already stated, there is a thermal sensor in the bottom of the unit. Plug it in upright, no problem. Upside down, heat rises. To where? Ah, you guessed it! The thermal sensor! It says to itself, "Boy! These cells are getting way to hot! Let's shut'er down!"

Have you ever heard of making moutains out of molehills? :naughty:

Dave


----------



## Mr Happy

45/70 said:


> Correct me if I'm wrong Mr H, but I believe if the vent holes actually "vent", you loose electrolyte regardless of the cells position.


Ah, but, it's those electrons, you see. They are very tiny and they can escape out of the vent holes and evaporate without any visible sign of leakage.


----------



## 45/70

Mr Happy said:


> Ah, but, it's those electrons, you see. They are very tiny and they can escape out of the vent holes and evaporate without any visible sign of leakage.



Please, do tell me more about electron evaporation. For example, at what temperature (F,C, or K) do these bad boys evaporate?

Sorry, OT. I'll stop now. :devil:

Dave


----------



## Black Rose

Not sure which is more funny, the Sanyo comments or the resultant conversation :laughing:


----------



## TorchBoy

Strangely enough, my father has recently noticed that his GP 2 hour charger terminates much more reliably when it's vertical. When he plugs it into a distribution board on the floor (so the charger is flat) he says it repeatedly overcharges the cells and they end up stinking hot (metaphorically) for a long time. I presume this implies there's a thermal sensor in the top of the unit.


----------



## Bones

Mike86 said:


> ...
> I finally received a reply stating:
> 
> “The batteries contain electrolytes in liquid form. If they are charged any other way than upright, it is possible that you will not get a 100% charge every time.
> ...



There is also this conundrum; SilverFox conducted a little experiment in this regard, and actually noted a fairly significant capacity increase compared to when the same cells were charged upright:



SilverFox said:


> ...
> The results from charging them [upright] in the Eneloop charger:
> 
> 1890
> 1918
> 1928
> 1893





SilverFox said:


> ...
> I was also wondering what would happen if you charged with the unit plugged in upside down.
> 
> In my case, it seems to do a better job of charging.
> 
> Same Eneloop cells with the charger plugged in upside down gave me
> 
> 1987
> 1999
> 1984
> 1992
> 
> Keep in mind that Your Mileage May Vary...



How do you suppose Sanyo would react if a whole bunch of us insisted that our chargers and Eneloops be replaced as faulty if they too deliver more capacity when charged upside down?

I can imagine the conversation should word of this reach the boardroom:

"Are you telling us that our customers are returning a flagship rechargeable products in droves because they're delivering to _much_ capacity!"


----------



## Mike86

Bones said:


> If the cells should to be upright to charge, then wouldn't the same thing apply when they are discharged?
> 
> Perhaps you will find that your camera will take fewer shots when repeatedly used in positions other than upright.
> 
> Or would the opposite apply, and the cells should be positioned upside down when being 'drained' of their energy?
> 
> I'm so confused ...




I'm confused too. 

When I asked if the charging position is critical due to the electrolyte, I would think the discharge position would also be critical. I also said that my camera uses 4 AA cells, two upright & two upside down. Does this mean they are going to discharge differently?

Somehow I feel compelled to joust with those Sanyo reps. I guess I have too much time on my hands right now.


----------



## Mr Happy

Mike86 said:


> When I asked if the charging position is critical due to the electrolyte, I would think the discharge position would also be critical. I also said that my camera uses 4 AA cells, two upright & two upside down. Does this mean they are going to discharge differently?


All joking aside, you can be assured to know that there is no free liquid electrolyte in an NiMH cell. The electrolyte is absorbed into a porous membrane and held there by surface tension. It cannot move around under gravity and the orientation of cells in charging or discharging will make no difference. 

For reasons that I can't remember at the moment the amount of water included in an NiMH cell is reduced to the absolute minimum with no excess at all. This is why any venting of a cell, for example if it gets too hot on overcharging, is an irreversibly bad thing. There is no surplus of water inside to compensate for any losses.


----------



## SilverFox

Hello Mr Happy,

I have to agree with you... I keep shaking the Eneloop cells I am using for the 15 minute charging cycle testing, and I can't hear any sloshing around at all. Also, there is no "boiling" sounds at the end if the 15 minute charge.  

However, I may disagree with you about the gravitational effects on cells. There is some evidence that if a cell is stored for an extended period of time, the electrolyte is effected by gravity. This results in starving part of the separator. This is what causes the cell to heat up if it is charged normally the first time, instead of using the 0.1C charge. The 0.1C charge tries to redistribute the electrolyte evenly throughout the separator. 

It takes a long time for this to occur, but after 3 - 4 years sitting on the shelf, it seems to happen.

In normal use this is not an issue, and has nothing to do with normal charging either upside down, laying down, or right side up.

Tom


----------



## cy

finally got several sets of eneloops to try out...


----------



## Mike86

Since I had nothing to do the other day I contacted Sanyo again in response to their comments about the separately packaged batteries having no instructions about charging in an upright position.

They answered “It still implies to when he charges his batteries in another charger.”

And their comment “I do not know about other brand of chargers, but it is likely they all say the same thing on their instructions about the batteries not fully charging to their full potential.”

I responded that I have two other chargers and neither one has instructions on charging right side up & one is made to lay flat. So how would anyone know it is implied that eneloops have to be charged upright even if used in another charger?

I even gave them an opening for a different answer and suggested that maybe it is their charger's requirement. I said perhaps there is a temperature sensor located at the bottom
and turning it upside down puts the sensor at the top. Since heat rises, the sensor will get hot faster & turn off the charger too early. Could this be the reason?

Here is their response. Obviously their Customer Service dept has no idea and does not care about finding the answer. 
------------------------------------------

Sanyo advises to charge in the upright position. It's
suggested to do so because of the following reasons stated
in the previous email.

Best Regards,

Customer Service
Sanyo Energy (U.S.A.) Corp.
http://www.eneloop.com
http;//www.sanyobatteries.com


----------



## 45/70

Well, OK. Since I don't have _*any*_ NiMH/NiCd chargers that are upright, I guess I'm going to have to figure out how to prop them all up somehow, so I can charge my eneloops. :sigh:

Anybody hear anything more about that job opening yet? :thinking:

Dave


----------



## TorchBoy

*Re: Eneloop self discharge study*



Mike86 said:


> They answered “It still *implies* to when he charges his batteries in another charger.”


Not "applies"?

45/70: You could use the wire stand on the MH-C9000 to hang it on a nail banged into a wall. :naughty:


----------



## Unforgiven

You could always tell them you don't understand and ask for a photo illustration.


----------



## Mike86

*Re: Eneloop self discharge study*



TorchBoy said:


> Not "applies"?
> 
> 45/70: You could use the wire stand on the MH-C9000 to hang it on a nail banged into a wall. :naughty:




"Implies" is what they said, however "applies" would make more sense. That is if having to charge in an upright position made any sense in the first place.

But I'm still curious why instructions for 3 of their chargers state this.


----------



## Mike86

First of all, I am using eneloops in my digital camera and am happy with them.

But I was still “dancing” with Sanyo about having to charge the cells right side up. I sent them a letter over a month ago & finally got a reply the other day. I have found that sometimes writing a snail mail letter gets a more intelligent response, but not always.

I did mention that the separately purchased batteries made no mention of not charging upside down, that some chargers cannot hold the batteries right side up, and was it perhaps a requirement of their charger.

Sanyo replied: “In regards to your inquiry, it is recommended to charge in the upright position mainly because the liquid inside the batteries will overheat while charging. This recommendation is required for all our chargers and batteries. The Model NC-MQN05 charger with the sliding cover does not interfere with the temperature while charging.”

Good or bad, that is an official answer from Sanyo. But I’m just guessing that not a lot of eneloops are getting charged in the upright position and they still are working just fine.

Mike


----------



## pobox1475

After spending a solid month with my new C9000 continuously running break-in's on the cells I had laying around I finally had time to test (break-in) some new Eneloop AA's dated 2006. I know that this may or may not be beneficial to do. I am mostly curious about finding their capacity. Out of the first eight all but one came in at around 1920 mAh and the odd one was 1890. I have read that most users were getting labeled capacity and in some instances almost 100 mAh over. I must say I am a little disappointed, especially with the one that did not reach 1900. Should I run another break-in or refresh on that cell? I don't want it to be a weak link of sorts . Also for future reference what should they be charged at to get the best balance of output and life from them?


----------



## Mr Happy

What's the date on your Eneloops?

Most Eneloops I've tested come in between 1920 mAh and 1980 mAh. They are specified as min 1900, nominal 2000, so above 1900 is within spec.

My feeling is that older Eneloops manufactured in 2006 seem to test a bit lower than newer samples.

I also have a suspicion that the accuracy of the C9000 is not better than +/- 50 mAh per channel.

Lastly, Sanyo's graph of capacity vs. cycles does seem to show a small increase in capacity over the first few charges.

So overall, I wouldn't be too disappointed. The strength of Eneloops lies mostly in areas other than their capacity.


----------



## mighty82

From what I have experienced, the C9000 always shows about 100mAh lower capacity than the bc900 charger. My advanced computer charger agrees with the bc900 on capacity.


----------



## TorchBoy

mighty82 said:


> From what I have experienced, the C9000 always shows about 100mAh lower capacity than the bc900 charger. My advanced computer charger agrees with the bc900 on capacity.


The BC-900 doesn't rest an hour like the MH-C9000 does. The MH-C9000's algorithm more closely follows the IEC standard. What do your advanced chargers do?


----------



## riosaeba

Good Job!
So, if i have understood, the best ni-mh battery is eneloop 2000mah?
I have to use the metz mecablitz 58 with these battery and this mecablitz flash demands a lot of ampere.
Thanks.


----------



## Mr Happy

riosaeba said:


> I have to use the metz mecablitz 58 with these battery and this mecablitz flash demands a lot of ampere.



Hi,

:welcome:

Eneloops are good for lots of amps, so you should have no cause to worry.


----------



## EngrPaul

riosaeba said:


> Good Job!
> So, if i have understood, the best ni-mh battery is eneloop 2000mah?
> I have to use the metz mecablitz 58 with these battery and this mecablitz flash demands a lot of ampere.
> Thanks.


 
Also consider Imedion 2100 mAh

http://thomasdistributing.com/shop/product_info.php?cPath=122_104_106&products_id=1020&SP_id=68


----------



## Anders

Hello.

Here you can see the difference on high Amperage.








Anders


----------



## Turak

mighty82 said:


> From what I have experienced, the C9000 always shows about 100mAh lower capacity than the bc900 charger. My advanced computer charger agrees with the bc900 on capacity.


 
There are at least 2 MAJOR reasons that you get about a 50-100mAh difference between an MH-C9000 and a BC900. I actually have 2 of each and love them both for different reasons.

1. Because of changes made to the firmware of the MH-C9000, the charger actually DOES NOT always charge an Eneloop (and others) to its maximum capacity.

The MH-C9000 charger uses -detaV, maxV, and a timer limit for its termination methods. In the early models (F models), the chargers maxV was set much higher and the batteries would actually hit -deltaV.....but the problem was they were getting just a bit too hot. Maha decided to lower the maxV point to 1.47V. THis had the effect of causing many batteries, especially Eneloops, to hit maxV before they hit -deltaV. This in turn causes the Eneloops to come off the charger slightly under maximum capaity. If you check the charts, the Eneloops typically seem to hit -detaV somewhere in the 1.50 to 1.55 range. So ultimately more batteries seem to terminate now by hitting maxV instead of -deltaV with this charger.

The BC900 charger uses the same termination methods and also suffers from the same problem except that it's maxV is set at approximately 1.52V. More batteries seem to terminate by hitting -deltaV than maxV when using this charger. This is also one of the reasons that batteries come off a BC900 a little 'warmer' (besides the fact they are jammed in a smaller space).... they are actually closer to maximum capacity when they hit -deltaV than maxV.

Most 1.5V NiMh AA batteries tend to hit -deltaV anywhere from about 1.45V-1.55V.

2. As stated by someone else, the MH-C9000 rests between the charge/discharge cycles and thus some of the surface charge bleeds away.


----------



## SilverFox

Hello Turak,

You got most of the way the C9000 functions correct, but you forgot to mention the top off charge...

After it terminates the main charge, it charges at 100 mA for 2 hours before droping to its 10 mA trickle charge. Depending on the capacity of the cell, this usually ends up with the cell voltage in the 1.5 - 1.55 volt range and it being fully charged.

A major difference between the BC900 and the C9000 is that the BC900 begins the discharge immediately after charging, and the C9000 incorporates a rest period before discharging.

Tom


----------



## DualMonitors

SilverFox said:


> Hello Turak,
> 
> You got most of the way the C9000 functions correct, but you forgot to mention the top off charge...
> 
> After it terminates the main charge, it charges at 100 mA for 2 hours before droping to its 10 mA trickle charge. Depending on the capacity of the cell, this usually ends up with the cell voltage in the 1.5 - 1.55 volt range and it being fully charged.
> 
> A major difference between the BC900 and the C9000 is that the BC900 begins the discharge immediately after charging, and the C9000 incorporates a rest period before discharging.
> 
> Tom



Hi Tom, Turak, et al:

as a newbie, i'm trying to comprehend all this and put it in practical use.

Turak's post seems to indicate that the BC900 charges more "fully" more batteries, which seems like a "good thing".

Tom/Silverfox's post seems to indicate that the C9000 Maha's trickle charge at the end of 100 and then 10mA make the C9000 charge batteries more fully and somewhat more gently, yet still accomplishes the job of a complete charge at the end, even more elegantly so.

Tom's last paragraph of the BC900 beginning the discharge immediately while the C9000 incorporating a waiting period is not immediately clear to me: which is "better"? Is incorporating a waiting period superior? Is beginning the discharge immediately better? Also, is this referring the "refreshing" cycle when one wishes to condition and refresh an old, tired battery?

sorry for the newbie type questions...struggling to understand all this.

thx in advance!


----------



## SilverFox

Hello DualMonitors,

The discharge method depends on what you are testing for...

If you want the largest capacity number, and have an application that depends on the batteries being used "hot off the charger," you don't want any rest time.

On the other hand, if you are trying to check your cells capacity according to the IEC standards, a rest time after charging is required.

RC people generally use their batteries "hot off the charger," and if that is your intended use, it would be better to test in a way that simulates your usage. Most flashlight use is done some time after the batteries have been charged, so a rest period would be better when you are trying to check performance.

Hot chemistry is also able to hold higher voltages under load, so if your application is voltage sensitive, you would want to test immediately while the batteries are hot.

As you can see, there isn't a single answer to your question...

Tom


----------



## Turak

SilverFox said:


> Hello Turak,
> 
> You got most of the way the C9000 functions correct, but you forgot to mention the top off charge...
> 
> After it terminates the main charge, it charges at 100 mA for 2 hours before droping to its 10 mA trickle charge. Depending on the capacity of the cell, this usually ends up with the cell voltage in the 1.5 - 1.55 volt range and it being fully charged.
> 
> A major difference between the BC900 and the C9000 is that the BC900 begins the discharge immediately after charging, and the C9000 incorporates a rest period before discharging.
> 
> Tom


 
Hi Tom, DualMonitors, ....

DualMonitors - It does not matter which charger you get, the BC900 or the MH-C9000, they are both excellent chargers and both charge the batteries to within about 97-99% of their capacity...which is about the best your going to get with todays technology. I am just nitpicking some of the fine details about both chargers.


Tom - Hehehe.... No I didn't forget .... but i needed to leave more stuff for us to talk about....

Now that you have mentioned it.......

I agree that after the MH-C9000 terminates, typically at 1.47V (maxV) that it starts to apply a 100mA 'top-off' charge for 2 hours. I too have seen it terminate at 1.47V and then drift up to anywhere from 1.50 to 1.55V with the 'top-off' charge. But that's about it and with anything other than an extrmemly low mAh battery or the newer LSD batteries, the so called 'trickle charge' of 10mAh is just ridiculous. While the 10mAh rate might be adequate for a LSD cell, it should be closer to 25-100 mAh to keep up with a regular NiMh batteries self discharge.

Now.....as to the BC900. Well I have watched them terminate at 1.52V or even 1.53V occasionally, and then it proceeds to start a 'trickle charge' which is based on the charging rate you selected. Which it then proceeded to drift up to anywhere from 1.55V to 1.60V.

The manual for the BC900 says the trickle charge rate is around 5% of the charge rate which translates into anywhere from 10mAh for a 200mAh rate to 50mAh for a 1000 mAh charge rate all the way to 90mAh for the 1800mAh rate. Now this IS enough to keep up with the self discharge rates of regular NiMh batteries.

Personally, I wish BOTH of them had an adjustable trickle charge rate, along with an adjustable top-off charge rate and timer. Along with an adjustable maxV setting and an adjustable -deltaV rate.

I AM NOT trying to say that the BC900 is 'better' than the MH-C9000 or vice-versa. I am just pointing out some techinical details that I have tested and verified at my little table at home with 2- BC900's and 2 - newer MH-C9000's.....which is;

Given the following scenerio and the fact that you are using some newer batteries that have been exercised at least 5-10 times AND ARE WITHIN 50mA of each other when discharge tested (both are to improve testing accuracy).

If you put a BC900 (firmware 33) and a newer (rev G or H) MH-C9000 charger side by side for your test. It DOES NOT matter whether you grab the batteries off both chargers immediately after they both terminate (yes I know that your supposed to give the MH-C9000 an extra two hours) or even if you do wait the extra 2 hours (but this means leaving them on the BC-900 the extra two hours also to be fair) then test them......The BC-900 will almost always give you a fuller charge on a regular NiMh cell, but not necessarily on all the LSD cells (they seem to vary, even Eneloops).

Not to mention the fact that with the MH-C9000's two hour 'top-off' charge to get a 'full' charge.....seems to give the BC-900 an advantage in that overall it makes the BC-900 a 'faster' charger given that you use the same sharge rate in each charger. Mostly because.....the BC900 is terminating on -deltaV most of the time and applying a higher trickle charge afterwards.

Another thing to think about.....

If you follow the IEC standard of letting the cell rest an hour before testing it for capacity (which the MH-C9000 does).....then the self-discharge rate of the individual cell becomes a factor that skews your capacity test results that you are not accounting for. 

Probably the most interesting thing I find is that when I am comparing the manufacturers ratings against what a BC-900 rates a batteries capacity at and what an MH-C9000 rates a batteries capacity at.....the BC900 is closer almost ALL the time. Really makes me wonder if ALL the manufacturers aren't running thier tests on the batteries 'hot off the chargers'.....hehehe.


----------



## Codeman

Turak said:


> Hi Tom, DualMonitors, ....
> ...
> If you follow the IEC standard of letting the cell rest an hour before testing it for capacity (which the MH-C9000 does).....then the self-discharge rate of the individual cell becomes a factor that skews your capacity test results that you are not accounting for.
> ...



This is true from an intellectual basis only in regards to battery usage in flashlights, where the cells are probably going to be resting for periods of longer than an hour anyway. In that respect, niether charger will give an accurate estimation of the real capacity during use, but the C9000's rest period will result in a closer approximation.

Besides, any cell that looses enough charge during a single 1 hour rest period to be of concern probably can't hold a charge long enough to be useful anyway.

The 2-hour top-off period is of no concern to me. I prefer to pull my cells as soon as the C9000 indicates "done" because I'd rather have a slightly increased cycle life than that extra bit of charge. After all, the cell(s) is going to lose capacity regardless of the existence of a top-off period.

Which charger is "better" is far more dependent on the intended cell usage than any specific difference between the chargers without regard to cell usage.


----------



## SilverFox

Hello Turak,

Keep in mind that cells left in a charger with a higher trickle charge will end up beeing cooked to death. NiMh chemistry is more sensitive to this than NiCd chemistry, so this may indicate that Maha has finally introduced a charger for NiMh chemistry in particular, and LSD chemistry in particular...  

Another thing to keep in mind is that when cells are tested by the manufacturers, they are brand new cells. With the exception of the LSD cells, most of the cells we get are aged. Aged cells tend have less capacity than new cells, unless they are properly taken care of.

With this in mind, I may entertain an argument that if a charger is giving you rated capacity or over with aged cells, it is overcharging them... :devil: 

This may also be the reason that the standard testing is done after the standard 16 hour charge at 0.1C. This removes the "personality" of the charger from the equation.

Tom


----------



## Turak

SilverFox said:


> Hello Turak,
> 
> Keep in mind that cells left in a charger with a higher trickle charge will end up beeing cooked to death. NiMh chemistry is more sensitive to this than NiCd chemistry, so this may indicate that Maha has finally introduced a charger for NiMh chemistry in particular, and LSD chemistry in particular...


 
I totally agree with that. Leaving batteries 'trickle' charging on chargers for days at a time is surely slowly degrading that batteries performance and the overall number of cycles you will ultimately get out of it.

When I mentioned the trickle charge rates, it was not with the intention that you would leave a battery 'trickle' charging for any type of extended period of time. I personally, like to pull mine as soon as possible after they complete their charge cycle which is typically anywhere from right away up to about 3 or 4 hours. It was more from the perspective of truly overcoming the self discharge rates of a typical high capacity NiMh cell, which on a poorly perfoming cell can easily be 100mA per hour. Basically, the 10mAh rate on the MH-C9000 is useless other than with the LSD cells or low capacity batteries.



SilverFox said:


> Another thing to keep in mind is that when cells are tested by the manufacturers, they are brand new cells. With the exception of the LSD cells, most of the cells we get are aged. Aged cells tend have less capacity than new cells, unless they are properly taken care of.
> 
> With this in mind, I may entertain an argument that if a charger is giving you rated capacity or over with aged cells, it is overcharging them... :devil:


 
Ummm....the term 'overcharging' seems used very loosely when it comes to battery charging.

Referring to NiMh cells.... technically, you can not force extra capacity into the battery by 'overcharging' it. Once a NiMh cell has reached its maximum capacity, continuing to charge it or 'overcharging' as some like to call it, does not give you any more mAh.

What it does do however, is to cause a small voltage drop in the potential voltage. Also the internal chemical reaction going on starts forming more gas than can typically be reabsorbed back into the battery, not to mention the heat that is being created because it can not absorb any more energy. If this continues for any length of time, the battery can be slowly 'cooked' to death or even 'vent' the pressure in extreme cases.

As far as 'aged' cells go.....that's kinda reaching for it. 

For the first 3-10 complete charge/discharge cycles of a typical NiMh battery, it will actually increase its overall capacity as the chemicals and reactive materials become 'fully' activated/energized.

Depending on a few factors (i.e. were they ever charged, temperature stored at, if they were charged how low did you let them go before charging, etc.), a quality NiMh cell can easily go 3-5 years and still come within 5% of the manufacturers capacity ratings.



SilverFox said:


> This may also be the reason that the standard testing is done after the standard 16 hour charge at 0.1C. This removes the "personality" of the charger from the equation.


 
You could say the 'personality' of the charger is what I was referring to, in a manner speaking....

One point I was trying to make, was it seems that even though the MH-C9000 chargers 'break-in' function is supposedly closer to the IEC standard of testing the batteries capacity.......it is interesting that the BC-900 comes closer to the manufacturers rating about 80-90% of the time...at least in my limited testing.

Personally, I think that the fact that it uses a 2A load that is simply modulated using a duty cycle to give you a 'simulated' or 'averaged' overall charge rate has something to do with why the MH-C9000 is 'always' low on the capacity measurements when compared to manufacturers ratings.

Another point I was trying to make was ......

Because of the changes to the MH-C9000 awhile back to alleviate the heat build up in the cells (especially cells with slightly higher internal resistances) when charged at their default 1A rate, the MH-C9000 no longer teminates on -deltaV for 'most' batteries. It terminates on maxV most, if not all, of the time now.

A good side affect of this is that I think it makes it a bit gentler on the batteries overall, probably helping to give more overall cycles in the life of the battery. A bad side effect is that it tends to slightly undercharge the batteries when compared to a charger that is terminating on -deltaV (i.e. BC900) most of the time.


----------



## Bones

Turak said:


> ...
> When I mentioned the trickle charge rates, it was not with the intention that you would leave a battery 'trickle' charging for any type of extended period of time. I personally, like to pull mine as soon as possible after they complete their charge cycle which is typically anywhere from right away up to about 3 or 4 hours. It was more from the perspective of truly overcoming the self discharge rates of a typical high capacity NiMh cell, which on a poorly perfoming cell can easily be 100mA per hour. Basically, the 10mAh rate on the MH-C9000 is useless other than with the LSD cells or low capacity batteries.
> ...



Conversely, a 100mA trickle charge would grossly over-compensate for the self-discharge of most decently performing regular cells along with the low self-discharge cells.

In this regard, I think MahaEnergy got it right with the MH-C9000, especially considering the self-discharge rates will almost certainly continue to decrease as the low self-discharge technology evolves.


----------



## SilverFox

Hello Turak,

This brings up another consideration...

In evaluating various chargers, I have run comparisons of several chargers. I did these comparisons with a "test set" of cells that were giving me very similar performance from cycle to cycle. The chargers were used to charge the cells, then I let them rest for 30 minutes, then I ran a constant current discharge on my CBA II. 

The results I came up with indicated that the C9000 charged the cells a little more than the BC900 did. The C9000 charged cells came in at 2.462 watt hours and the BC900 cells came in at 2.355 watt hours.

I have not checked the accuracy of the discharge values from either the BC900 or the C9000, so I can't comment on the effects of their various discharge methods.

Tom


----------



## curtis22

Sanyo said:


> Sanyo advises to charge in the upright position. It's
> suggested to do so because of the following reasons stated
> in the previous email.
> 
> Best Regards,
> 
> Customer Service
> Sanyo Energy (U.S.A.) Corp.
> http://www.eneloop.com
> http;//www.sanyobatteries.com


One wonders which side is supposed to be "up". It isn't labeled.


----------



## Turak

Bones said:


> Conversely, a 100mA trickle charge would grossly over-compensate for the self-discharge of most decently performing regular cells along with the low self-discharge cells.


Quite true. There are a few 'better' methods they could have used though. One would have been to simply scale the trickle charge rate up based on either the charge rate or better yet, the battery capacity. Another nice method would have been to allow us to set the trickle charge and top off charge rates. The 'best' method would be to have the charger actually calculate the self-discharge rate and then automatically adjust the trickle charge rate based on that.



Bones said:


> In this regard, I think MahaEnergy got it right with the MH-C9000, especially considering the self-discharge rates will almost certainly continue to decrease as the low self-discharge technology evolves.


 
Like everything...Maha got a few things right but they also got a few things wrong too, in my opinion. Probably the number one thing I dislike the most would be the display. Lacrosse got it right with the BC900's display method of showing all 4 batteries at 1 time and no irritating auto rotation of the display. Maybe put in a selector to toggle between the two display methods....if anyone actually likes the current one....hehe. I also wonder what they were thinking with the 'high beam' display backlighting (it puts out more light than a couple of my flashlights). Another thing they got a bit wrong was the impedence test before charging....wayyyyy too conservative. Maybe make that a programmable option too or allow us to set the voltage threshhold. Their 'fix' to alleviate the problem where batteries with slightly higher internal resistances were coming off the charger a tad bit warm when charged at their default 1A rate that had a dramatic impact on the way the charger terminates now....wasn't the best approach either.

Don't get me wrong....I like the charger (actually have 2 of them). Those are just a few things that keeps a 'good' charger from being 'the perfect' charger.



SilverFox said:


> In evaluating various chargers, I have run comparisons of several chargers. I did these comparisons with a "test set" of cells that were giving me very similar performance from cycle to cycle. The chargers were used to charge the cells, then I let them rest for 30 minutes, then I ran a constant current discharge on my CBA II.


 
I'd like to hear bit more about what Silverfox thinks about the CBA II.


----------



## SilverFox

Hello Turak,

The CBA II is a great hobby device. It doesn't totally live up to its specifications, but it does a very good job at lower discharge rates.

Once you get it properly calibrated, and understand the influence of the lead wire resistance, it is also very accurate.

It is unfortunate that after 4 years they haven't addressed all of the initial issues, but when you are basically the only game in town you don't have to be motivated to improve your product. 

I still like it and recommend it, but it would be nice to see some competition for them that would drive improvements.

Tom


----------



## rdh226

Not sure if this thread is still considered alive or not, the last post being 6 months ago...


SilverFox said:


> Sanyo started the ball rolling with low self discharge NiMh cells with the introduction of their Eneloop cells. I, along with several others, have been testing these cells for roughly a year now and they seem to be holding up to the manufacturers claims.
> ...
> I am only going to project out to the year mark because I am going to be using my cells. Someone else can do the 1 year testing…
> Tom



OK; I decided to buy some and try them out myself. Bought 16 Eneloops from Thomas Bros.
Being Thomas Bros, I couldn't help but notice the Imedions too...so I bought 16 of them too.

Initially, I wasn't all that impressed. Off the shelf, all the batteries took a substantial charge;
For the Imedions, varied from 431mAh (not bad) to 1566mAh (not good at all); For the Eneloops,
varied from 621mAh (not particularly good) to 1263mAh (pretty poor, IMO). Although the
Imedions had the worst datapoint, overall they fared better than the Eneloops.

I then measured the first full-charge-cycle discharge capacity of each cell, then proceeded to
cycle them several times to break them in, as NiMH typically show a healty growth in capacity
with several break-in cycles. While neither set of batteries showed a dramatic improvement after
several cycles, the Imedions again won (slightly) over the Eneloops, showing only about 5%
growth in capacity, versus about 10% for the Eneloops (or, rephrased, the Imedions were closer
to providing full capacity more quickly).

I then put the fully-charged batteries aside, intending to test charge retention after a few months.

The days passed; the moons waxed and waned; the rivers rose and fell; the snows came and
went; Spring arrived. Merde! My batteries! After a full year, I "remembered" my batteries. Figuring
I had now toasted 32 expensive (well, relatively speaking) LSD batteries, I retrieved them and ran
them through their paces.

I stand *amazed*. After 1 year sitting neglected and ignored, my 16 Eneloops all boasted 1725mAh
to 1780mAh residual charge! *One Year!* Talk about _consistent_ performance, Wow! The Imedions
fared almost as well, with remaining charge varying from 1665mAh to 1895mAh, with one outlier
cell "failing" with less than 300mAh remaining charge.

All testing was performed on my LaCrosse BC-900s (0.5A max discharge, etc., and so forth).

In the table below, the columns mean:

* Cell -- Cell (or "battery") number, 1 to 16
* Initial -- Initial 200mA charge
* cy1 -- First capacity cycle: 200mA discharge from full charge, recharge at 500mA
* cy8 -- Eighth capacity cycle: 500mA discharge, recharge at 1000mA
* 1yr -- 500mA full discharge capacity after 1 year after cy8 charge
* 1ycy1 -- 500mA discharge capacity after 1yr recharge

Here are my Eneloop/Imedion charge capacity and charge retention results.

Maha Imedion AA 2100 April, 2008 buy

Cell.Initial..cy1....cy8....1 yr..1ycy1..
----+------+------+------++------+------+
#01 | 0813 | 2250 | 2320 || 1770 | 2300 | 
#02 | 0468 | 2240 | 2340 || 1730 | 2290 | 
#03 | 0446 | 2210 | 2300 || 1730 | 2240 | 
#04 | 1566 | 2280 | 2280 || <300 | 2260 | 
#05 | 0433 | 2250 | 2360 || 1845 | 2300 | 
#06 | 0441 | 2270 | 2380 || 1895 | 2310 | 
#07 | 0930 | 2250 | 2410 || 1550 | 2330 | 
#08 | 0520 | 2200 | 2300 || 1720 | 2250 | 
#09 | 0541 | 2250 | 2340 || 1650 | 2270 | 
#10 | 0523 | 2250 | 2370 || 1855 | 2310 | 
#11 | 0559 | 2290 | 2390 || 1825 | 2340 | 
#12 | 0541 | 2240 | 2340 || 1720 | 2300 | 
#13 | 0800 | 2270 | 2340 || 1810 | 2310 | 
#14 | 0429 | 2180 | 2310 || 1830 | 2260 | 
#15 | 0431 | 2220 | 2320 || 1665 | 2260 | 
#16 | 0814 | 2200 | 2260 || 1855 | 2230 | 



Sanyo Eneloop 2000 April, 2008 buy

Cell.Initial..cy1....cy6....1 yr..1ycy1..
----+------+------+------++------+------+
#01 | 1188 | 1943 | 2170 || 1780 | 2140 | 
#02 | 0643 | 1870 | 2110 || 1760 | 2060 | 
#03 | 0908 | 1920 | 2130 || 1765 | 2090 | 
#04 | 0733 | 1980 | 2120 || 1770 | 2100 | 
#05 | 0768 | 1930 | 2150 || 1750 | 2110 | 
#06 | 0621 | 1842 | 2100 || 1720 | 2060 | 
#07 | 0748 | 1888 | 2120 || 1725 | 2080 | 
#08 | 1210 | 1971 | 2150 || 1720 | 2110 | 
#09 | 0720 | 1890 | 2140 || 1730 | 2120 | 
#10 | 0724 | 1892 | 2140 || 1745 | 2090 | 
#11 | 0650 | 1920 | 2170 || 1755 | 2120 | 
#12 | 0730 | 1960 | 2150 || 1735 | 2110 | 
#13 | 1263 | 1920 | 2150 || 1755 | 2120 | 
#14 | 0687 | 1871 | 2120 || 1730 | 2080 | 
#15 | 0692 | 1947 | 2170 || 1775 | 2130 | 
#16 | 0713 | 2000 | 2190 || 1765 | 2150 | 


I was very favorably impressed with how both the Eneloops and the Imedions performed, excepting
one "bad" Imedion (well, 31 out of 32 batteries ain't too bad, in my experience).

I don't care if "traditional" NiMH can provide higher per-cell capacity, this breed of LSD cell/chemisty
is clearly a winner, and far more practical to use, effectively matching LiIon cells for overall charge
retention (set aside and forget capability).

Overall, I give "first place" ever so slightly to the Eneloops for their more-consistent cell-to-cell per-
formance. But the Imedions (well, 15 out of the 16 of them) did manage about 10% more charge 
capacity, which is significant and would I suspect place them "first place" in most folks' opinions.

Yay!

-RDH


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## BentHeadTX

Thank you for the one year results, you are either very patient or forgetful!  

I have converted to all Eneloops myself and will remain true to their cause. My family understands that WHITE cells are rechargable so all is well. 

Good to hear the numbers on my favorite battery, they work well and maintain their charge for a loooong time.


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## rdh226

BentHeadTX said:


> Thank you for the one year results, you are either very patient or forgetful!


 Forgetful gets most of the credit here...sigh. Still, 'twas a useful forgetful.

-RDH


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## SilverFox

Update:

In March of 2006 I ordered and set aside some Eneloop AAA cells. I just got to the point where I needed them, so I decided to see how much capacity they had left.

The cells were stored at room temperature for these 3 years.

They ended up with about 550 mAh of capacity. This is about 74% of their original capacity.

Not too bad... 

Tom


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## Black Rose

You're the master of understatements 

Were those cells charged before being stored or was that capacity out of the package? Either way, that's impressive.


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## Burgess

Wow ! ! !



That was before i even joined CPF ! 



Good information, SilverFox.


:goodjob::thanks:

_


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## digitor

Whoops, I got it wrong....


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## ICUDoc

Great data thanks rdh226 and silverFox.


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## Bullzeyebill

Tom, would you say that they were about 85-90% capacity when you got them, reading in the neighborhood of 1.33 volts or so each? If so then that is very good to have lost so little in three years.

Bill


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## SilverFox

Hello Black Rose and Bill,

With the original release of Eneloop cells in Japan, the cells were fully charged before being distributed for sale. I just took them out of the package and discharged them to see how much was left.

Tom


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## Gazoo

Well I have an update too. I had 4 eneloop AA's that have been sitting around and I needed them also. These were manufactured in Aug 2006. I don't know the exact date I tested them but it was about a month ago. Testing was done with the Maha Wizard charger firmware revision 0G0C01.

The capacity of the batteries follow:

Battery 1: 1380
Battery 2: 1386
Battery 3: 1344
Battery 4: 1398

All batteries were discharged at 500ma and were a fresh set out of the package when I tested them. Not too shabby considering they had been sitting in the package for all that time.


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## windstrings

Has anyone considered these yet? 2300mah "*Tenergy Pre-charged RTU NiMH AA 2300mah Rechargeable Batteries"

*


> *85% residual capacity after 1 year of storage and 70% residual capacity after 2 years of storage *


The reviews aren't so hot on them.... has anyone found anything better than the eneloops or the Eneloop/Imedion's yet?


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## windstrings

Another question...... has anyone determined how bad it hurts shelf life when leaving these batteries in a hot car inside a device on a regular basis?


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## UnknownVT

windstrings said:


> Another question...... has anyone determined how bad it hurts shelf life when leaving these batteries in a hot car inside a device on a regular basis?



Eneloops Left In Car For 1 Year - Results


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## Radiophile

This thread is referenced by the California Integrated Waste Management Board as Technical Information about Rechargeable Batteries by a staff person who is an avid user of rechargeable batteries:

http://www.ciwmb.ca.gov/WPW/Power/RechBattInfo.htm

:thumbsup:


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## windstrings

I bought some Imedion's, just take note they are slightly bigger in diameter than regular AA's.

They fit very tight in a light I have that works fine with eneloops or duracell lsds.

The difference is almost not noticeable....


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## samgab

Excellent study there Silverfox, thanks. I know it was first posted a long time ago now, but I wanted to bookmark it. Cheers! I wonder how the eneloops tested in your study here would compare side-by-side with the newer improved version eneloops? I wonder if they discharge similarly at 2A, 3A, 4A, etc; and if there is any improvement there, or if the improvement is just in the self-discharge rates and the number of claimed cycles per cell lifespan... Some of the new AA devices have pretty high current when the voltage starts to dwindle. I also found Anders' graph interesting, comparing the eneloops to the Imedion cells at higher discharge rates. The eneloops really shine there.


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## pobox1475

When I first saw the _new and improved_ AA''s I thought MUST HAVE. Then luckily quickly realized that additional 500 recharges over the original 1000 is not reason for me to spend moola. With an ample supply on hand and not using daily mine should last years anyway. Do wonder if there are any other advantages beyond the additional 50% charging cycles?


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## Wrend

http://www.eneloop.info/home/the-new-improved-eneloop.html


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## mattchase

Rise from the dead, old thread...

I just got caught up on this thread and saw Windstrings question about leaving batteries in the car (is 2 years too long to wait for a reply?). I haven't done any more "quasi-scientific" tests but I have continued doing many real world tests. Since that time I've continued to use those same Eneloops in a couple of flashlights that stay in my car at all times, and every time I have needed to use one of those lights they have worked perfectly. I know I've charged them a few times after using one of the lights, but literally only a few times, in 4 years of being left in my car. I haven't had any of them leak or explode, and I've only had 1 battery fail completely so far from the original group of 18 that I bought in 2007! Though I also had 6 of those original 18 stolen a few years ago (along with a sweet modified Mag  ) so I can't say if those 6 still work or not (I'm sure they do...assuming the thief figured out how to charge them). But of the ones I have remaining, excluding the one that failed, the rest are still in service.

I'm sure by now many others have done these same real world tests and Eneloops have been out long enough that everyone knows how great they (and other LSD) batteries are. Just thought I would share that they still work well after about 4 years of being left in my car - still in the Texas heat, still no covered parking.


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## Kestrel

I've got four unopened NIP Eneloop AAA's mfg 5 years ago. As I'm a rather patient person, I think I can wait for another five years before sending them to SilverFox for 10-year testing, LOL. Plus I have a pair of NIP AA 'Shnoopaloops' (remember that closeout? ) from 2008, so it would be cool to test those after they hit their 5-year mark.


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## MagPap

Hi there:

I'm new in CPF :wave: , and I would like to make a question regarding eneloops. I have search it in the board but not found an specific response, so I post it here.

I have read one of advantages of LiOn batteries over NiMh are their low rate of discharge. How it compares to eneloops? Which are better in this field?


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## SilverFox

Hello MagPap,

Welcome to CPF.

I believe Li-Ion cells still have the advantage, but the low self discharge rate of the Eneloop and other cells has closed this gap a lot.

Tom


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## Wrend

I'm not sure if that's the case or not. I haven't seen much in the way of actual independent numbers regarding Li-ion type self discharge rates. Some of the advertised rates of LiFePO4 cells/packs from vendors I've seen are listed as having several times the average self discharge rate that Eneloops have and they advertise it as having good low self discharge performance, for example.

According to Wikipedia, average self discharge rate of Li-ion cells is about 5% to 10% per month or about 8% at 21 degrees Celsius per month. The current "1500" cycle Eneloops are supposed to hold about 75% of a full charge after 3 years. This at least indicates that Eneloops have roughly 10 times better self discharge performance on average after 3 years.

Either way, it's so low with Eneloops that for all but very niche applications (not really any I can even think of off hand) it isn't an issue.


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## samgab

I'm currently reading the book "Batteries in a Portable World: A Handbook on Rechargeeable Batteries for Non-Engineers" which contains a lot of useful info.
It seems Li-Ion self-discharges at sometimes as low as 2-3% per month, depending on the specific chemistry (eg: LiFePo4 is quite a bit higher).
Standard NiMh cells are as high as 30% per month rate of self-discharge.
eneloops are as low as 0.5%-2% per month or less (the new ones lose 10% in the first 6 Months, then another 5% in the following 6 Months, then another 5% in the following 12 Months, and another 5% in the next 12 Months and so on - http://www.eneloop.info/home/performance-details/self-discharge.html ).

So eneloops and li-ions are nearly on par in terms of rate of self discharge.
See also http://en.wikipedia.org/wiki/Loss_of_charge although it would be better if they quoted more sources for the figures they quote.


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## Wrend

> So eneloops and li-ions are nearly on par in terms of rate of self discharge.



I don't follow. According to the info you posted, it looks like in a worst case scenario for Eneloops they'd be on par with Li-ion cells, but typically and on average they'd be several times better.


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## samgab

Wrend said:


> I don't follow. According to the info you posted, it looks like in a worst case scenario for Eneloops they'd be on par with Li-ion cells, but typically and on average they'd be several times better.



Without getting into the nitty gritty... No, they aren't the same, eneloops _are _a little bit better, from what I've read. But there are so many variables; how old, how many cycles, what device are they in, what temperature are they stored at, what state of charge were they to begin with, vampire discharge from the electronic protection device often attached to the li-ion if any... and the self-discharge curves aren't linear, they start out steeper and level out somewhat... It can't be stated as a simple "2%" and that's it. So in the bigger picture, yeah, they're NEARLY on par... Not exactly the same.
But it's all a matter of context. I realise you like to be precise, having read your posts about how you finely balance your eneloops, so no, from your point of view, they aren't nearly on par. For most people's purposes, I'd say they are _pretty _close for self-discharge rates... 
But eneloops are the best (lowest) rate of self-discharge I've seen yet for a secondary cell of any chemistry. Especially the yet-to-be-released 1800 cycle version.


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## Wrend

Thanks for the clarification.

Yes, I agree that what's important to most people is that when they go to use a battery powered device that it still works even though it's been a while since they last used it or charged the cells in it.

Now if I could just get a cell phone that runs on AAs.  (The Li-ion cell in my phone definitely isn't up to the specs talked about here any more).


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## MagPap

Wow. Thanks for the useful info!!! lovecpf

In resume, since there is not a great difference between Lions and eneloops in LSD rate (altough the latter are somewhat better), I asume is safe to say that LSD rate won´t be the first factor to choose between the two (in a flashlight that can use both, of course..)


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## led2011

This is very interesting and awesome. Thanks for all your hard work.
Would you offer me some similar graph about Eneloop 18650 Li-ion rechargeable battery, if you have been interested in it.


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## SilverFox

Hello Led2011,

Eneloop cells are Ni-Mh chemistry and not Li-Ion chemistry.

Tom


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## led2011

Thanks for silverfox's great hard work in being specailaizd in doing researches in battery.

Good for FYI when i plan to buy battery next time.


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## UnknownVT

eneloop (Duracell Pre-Charged) long term report (2+ years) (link)

Summary:
1 set of 4 Duracell Pre-Charged (white top made in Japan confirmed eneloop re-badges)
usage/stored idle in Pentax K100D dSLR camera for nearly 2.5 years.
(renown for being very battery fussy, please see 
eneloop vs. Kodak Pre-Charged Voltage Maintenance) 

After a total of 738 shots - 623 of which were in the first month after battery installation - with the camera mostly idle and only very occasional usage - 
Maha C-9000 discharge at 400mA (=1/5 or 20% capacity current) -
Remaining capacity and discharge times:

472 mAh (78min)
485 mAh (81min)
461 mAh (76min)
455 mAh (76min)

This looks pretty impressive to me as it is nearly 2.5 years (2 years 4 months 24 days) since charge - and there seems to be still nearly 1/4 capacity, also after having taken 738 shots -

Extrapolating this - it means a theoretical shot count of 955 shots 
(I used the lowest 455 mAh remaining capacity, and 2000mAh as the full capacity - 
worst case figures).

Just to put this into context I was getting on average 1,000 shots/charge - 
so having these DP-C idle for nearly 2.5 years since charge does not seem to have reduce the theoretical shot count.......


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