# Eneloop & Enduro LSD Duration Testing



## modamag (May 22, 2006)

*Eneloop & Enduro LSD Duration Testing (60 days update)*





































*=== Testing Details ===*
1. Cells repeatedly formed @ 200mA for 16 hr to determine "max" capacity.
2. Charging method:
- LaCrosse 200mA pre-charge (allow minimal resting time difference)
- Triton final-charge with 5mV dT (assure the same end charge condition)
3. Standard storage at room temperature (Bay Area/CA) 65-80F (18.3-26.7C).
4. Frozen storage at refrigerated temperature 10F (-12.2C).
5. Frozen cells are thawed for 8-10 hrs prior to testing.
6. Discharge rate of 1.0 A
7. CBAII Details:
- Software version 1.0.8.1
- 0.019V offset
- (-)8mA offset
- Temperature 
- Powerpole to Battery Test Clamp


*=== Interpretation ===*
Vavg - voltage average - higher value result in brighter output in the same "unregulated" light.
Delta Vavg - how much Vavg change over storage time.
Vsd - voltage standard deviation - larger value result in more constant output.
Delta Vsd - how much Vsd change over storage time.
Current Capacity - how much capacity you'll really get @ 1A discharge.
Delta CC - how much CC change over storage time.
Power Capacity - how much *power capacity* you'll really get @ 1A discharge.
Delta PC - how much PC change over storage time.
Runtime - how long you'll get the constant 1A discharge.
Delta RT - how much RT change over storage time.


*=== FAQ ===*


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## Trashman (May 23, 2006)

*Re: Low Self Discharge Duration Testing*


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## CroMAGnet (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

I like my Titanium 2700 NiMHs but let's see you leave them in a light in the closet for six months! But isn't that what L91's are for? :shrug:


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## Handlobraesing (May 23, 2006)

*Re: Low Self Discharge Duration Testing*



modamag said:


> Well, all this hupla about low self discharge cell have got me going.
> I was lucky enough to get a small sample from Amondotech (Thanx Wayne) for testing.
> 
> I want to conduct compare them versus your typical 2500 mAh cell of the day to see where the strong and weak points are.
> ...



What is the charge method? Quick charging can vary in termination point and introduce error. 

I always use low current, timed charge method. For the purpose of testing, I think it is a great idea to use the testing current used by the IEC, which is 0.1C (270mA for 2.7Ah cell, 250mA for 2.5Ah and so forth) for 16 hours.


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## wptski (May 23, 2006)

*Re: Low Self Discharge Duration Testing*



Handlobraesing said:


> What is the charge method? Quick charging can vary in termination point and introduce error.
> 
> I always use low current, timed charge method. For the purpose of testing, I think it is a great idea to use the testing current used by the IEC, which is 0.1C (270mA for 2.7Ah cell, 250mA for 2.5Ah and so forth) for 16 hours.



Are you going to use low current all the time? How C/D low current cycles do you perform? Better off charging the cells the way you are normally going to charge them! You only need to charge at 1/10C the first cycle anyway.


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## Handlobraesing (May 23, 2006)

*Re: Low Self Discharge Duration Testing*



wptski said:


> Are you going to use low current all the time? How C/D low current cycles do you perform? Better off charging the cells the way you are normally going to charge them! You only need to charge at 1/10C the first cycle anyway.



The number of cycles is debatable as the datasheets do not specify number of cycles before full capacity is achieved. For testing purpose, its best to use laboratory conditions that is easily duplicated elsewhere.

Person A tests brand A 2500mAh using his XYZ smart charger.
Person B tests brand B 2500mAh using his ABC smart charger. 

Person A produce a report of 2300mAh with 500mA discharage to 0.9V
Person B produce a report of 2500mAh avg with 500mA discharge to 0.9V

The problem here is that because charging conditions are different, we don't know which batteries are actually superior. The difference could be a result of the difference in charge algorithm. 

If on the other hand, you use C/x rate for x hours, the charge method is reproduceable anywhere, allowing more accurate assesment of true battery performance under identical test conditions.


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## Scimmia (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

I'm not sure I see the point of this graph. You're comparing a 2100mAh rated battery against 2500-2700mAh rated batteries? Is anyone suprised they didn't last as long? The Enduro registered about 7% less than it's rated capacity on your test, while the Energizer was about 6.7% less, the Ti-2600 was about 13.8% less, and the Ti-2700 was about 8.4% less. I'd say things don't look very good for the Ti-2600, everything else is as expected.

What I really want to see is a test of the low self discharge feature.


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## wptski (May 23, 2006)

*Re: Low Self Discharge Duration Testing*



Handlobraesing said:


> The number of cycles is debatable as the datasheets do not specify number of cycles before full capacity is achieved. For testing purpose, its best to use laboratory conditions that is easily duplicated elsewhere.
> 
> Person A tests brand A 2500mAh using his XYZ smart charger.
> Person B tests brand B 2500mAh using his ABC smart charger.
> ...


The problem with using C/x is that you must discharge the cell(s) fully before using this method of charging but not everyone has the means to do so!


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## modamag (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

I'm currently using a 200mA charge rate, 5mV dV then 15mA trickle for a total of 20hrs.

Typically you want to do low current C/D cycles until the capacity no longer increase to record the maximum cell capacity. This can range anywhere from 3-8 cycles in my experience.

Guys also keep in mind that there is also cell-cell variation which I can not account for in this test due to limited sample size.

I would also like to observe the temperature effect on self discharge so 1/2 of the test will be conducted at room temperature ~70 F while the other half is held in refrigerated environment < 30F.

*The main purpose of this study is self discharge among different cells with variation of storage temperature.*


*Scimmia: *Keep in mind that I'm doing 1A discharge to reflect more closely of how we use the cells not 0.1C (or was it 0.2C) discharge, what the manufacturer usually use for capacity gauge.

This is only the begining of the test to see the "low self discharge" and where/when it's more appropriate to use LSD vs high capacity NiMh regardless of $$$.


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## Scimmia (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

I realize that you're draining them much faster than they were meant to be, and I wasn't complaining about the capacity being less than rated, I was just pointing out that everything was just as should be expected, and I don't think your comments about a "Pretty weak start for the Enduro 2100 mAh" were warrented.

I'm very interested in seeing the final results of this study. Do you have any guess what the running time will be on it? I guess I'm not expecting any real results for atleast a couple of months.

If I may ask, how are you planning on testing? Checking voltage every week (or few days, or whatever)?


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## modamag (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

My bad not clearly understanding the writing.

I guess I had a "high expectation" where I was hoping that the labeling is a mistake.
2100mAh (standard) was technology of 2 yrs pass. I was expecting a little more 

Discharge curve will be posted weekly for the first two months and then every other week.

I plan to carry this on for 4-6 months duration. Typically the majority of my cells are cycled periodically w/in 6 month period.

Just as a clearification, the main comparison is single cell over time not model vs models


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## JimH (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

Jonathan,

What are you using to measure wh?


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## modamag (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

Simply math my friend. <giggle>

Wh = Ah * Vavg
Wh = I(discharge) * Time (hours) * Vavg

I wish I have that fancy contraption that you recently acquire. Maybe I'll head over your house with couple water guns ... start shooting your dogs ... as they bark and you go outside to check what's all the fuss about ... I'll climb up the rear balcony, then down the stair to borrow that fancy unit </end grin>

BTW: glad to see you're back fromt he 18 hrs work day in 1 piece.


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## Scimmia (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

Ok, thanks for the clarification, but I guess I'm still not understanding something here.

I assume low self discharge means exactly what it says, if you charge them and let them sit on the shelf, they won't discharge as quickly as a regular NiMH battery would, as in dead a few months later. If I'm wrong in this assumption, I sincerely apologise.

Assuming I'm right, do you have a large number of these cells that you're testing? A 4 month trial like you're describing would require 12 of each cell, and even then there's no way to account for differences in the individual cells.


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## JimH (May 23, 2006)

*Re: Low Self Discharge Duration Testing*



modamag said:


> Simply math my friend. <giggle>
> Wh = Ah * Vavg
> Wh = I(discharge) * Time (hours) * Vavg


Aw shucks - I thought you had bought some new toy for me to drool over or at least were using calculus to integrate the area under the curve.




modamag said:


> BTW: glad to see you're back fromt he 18 hrs work day in 1 piece.


Survived the last 2 (back to back), but today is another one.


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## big beam (May 23, 2006)

*Re: Low Self Discharge Duration Testing*

I was going to get some ti's but looks like eneloop's hold higher voltage under load.Maybe I should wait for more testing befor I buy some


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## billgr (May 26, 2006)

*Re: Low Self Discharge Duration Testing*

i've bookmarked this thread. i'm most interested in finding out whether these are the "real deal"!!


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## modamag (Jun 11, 2006)

*Re: Low Self Discharge Duration Testing*

**** Update ****
I'm sorry for the lack of updates recently. An unexpected work travel have tempered my weekly update plan. So I'll try to update the data every other week instead.

Original post have been updated with pure data and testing methodoly.
I have also received a small sample (4x) of Sanyo Eneloop cells from my friend dat2zip for testing.


**** Discussion ****
So far after two weeks of sitting on the shelf, all the standard (chemistry) cells still outperform the LSD Enduro. Most likely by mid-week three the LSD will overtake the 2500s.

The interesting result so far have been the refrigeration process. Frozen standard chemistry cell retained their capacity even better than LSD @ minor cost to the grid bill.

The most surpising result is that LSD doesn't seems to like the frozen process, Vavg drop significantly when this happened. It might be too early to conclusively tell at this point, we can be more certain once we get the next couple sets of frozen data.


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## modamag (Jul 10, 2006)

*Re: Low Self Discharge Duration Testing*

**** 30 days Update ****

**** Discussion ****
I'm quite disappointed with all this low discharge hopela. If you look at the summary the percentage of self discharge of the Enduro & Eneloop are pretty much the same as the other Titanium.

What's the deal? Have anyone else with LSD cells seen similar phenomenom?

The Eneloop cell are really nice. The voltage underload for these things is exactly as Silverfox reported earlier. They maintain their load pretty well at high current draw.


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## altis (Jul 10, 2006)

*Re: Low Self Discharge Duration Testing*



modamag said:


> The most surpising result is that LSD doesn't seems to like the frozen process, Vavg drop significantly when this happened. It might be too early to conclusively tell at this point, we can be more certain once we get the next couple sets of frozen data.



Might be summat to do with the deionised water freezing:
http://www.stevesforums.com/forums/view_topic.php?id=96500&forum_id=51


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## Bullzeyebill (Jul 23, 2006)

Tom's Eneloop duration testing is showing an average of 4% loss in capacity a month for three months, so far. What is he doing different?

Bill


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## SilverFox (Jul 23, 2006)

Hello Bill,

One difference is that I am discharging at 0.5 amps. I don't think that is enough of a change to make a difference...

We will have to see what Jonathan comes up with at 90 days for comparison.

Tom


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## LumensUK (Jul 23, 2006)

The most significant item in differing eneloop results may turn out to be storage temperature. Sanyo encloses printed information in eneloop packs recommending storage temperatures between -20C/-4F and +30C/+86F. Note that quite low recommended maximum storage temperature.

The usually quoted information for NIMH batteries is self-discharge doubles with every 10 degree C, 18 degree F increase in temperature.


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## modamag (Aug 10, 2006)

*Re: Eneloop & Enduro LSD Duration Testing (60 days update)*

**** 60 days Update ****
After two months of data, we finally got something substantial.
The remaining capacity of the Eneloop & Enduro finally surpass the 2500 mAh cells.
It seems like the self discharge of the LSD cells are tapering off, while the regular cells (like the bunny) are "still going".

Some other interesting data is that the average voltage is starting to show sign of degradation for the normal cells while the LSD cells changes are in the noise level.
Eneloop voltage underload is trully remarkable. Even after two months of resting the average voltage is above 1.2V

There is something weird about the Ti-2600 (60 days non-frozen) data. There is a relatively large capacity drop when compared to the 30 days data. I will have to mark this cell and retest the case.

As the resting period increase, and the test go on, my # of free cells have dwindle. So the frequency of update for these data will also slow down abit.


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## Erasmus (Aug 22, 2006)

Nice work modamag!


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