All my eneloop XX 2500 mAh batteries dropping like flies

[WalkIntoTheLight]

With regular Eneloops, I wouldn't worry about trying to maximize cycles. Even if you only get 25% the rated 2100 cycles, that's still way more than most people will ever do.

For the Pros, it sounds like age is killing them more than the number of cycles.

 

[Gauss163]

For the Pros, it sounds like age is killing them more than the number of cycles.

Not necessarily, since they might have also been killed by a much smaller number of very deep cycles (or other usage that highly accelerates degradation).

 

[Gauss163]

With regular Eneloops, I wouldn't worry about trying to maximize cycles. Even if you only get 25% the rated 2100 cycles, that's still way more than most people will ever do

2100 cycles appears to be greatly exaggerated marketing hype, since AACycler's tests show between 300-400 cycles to 80% capacity (or 100mΩ) for 2 samples, and 620 for another - see below. So you should worry about even for regular Eneloops if you are doing anything that might accelerate degradation.

The Pros degrade 3-4 times more quickly.

 

[WalkIntoTheLight]

2100 cycles appears to be greatly exaggerated marketing hype, since AACycler's tests show between 300-400 cycles to 80% capacity (or 100mΩ) for 2 samples, and 620 for another - see below. So you should worry about even for regular Eneloops if you are doing anything that might accelerate degradation.

Were those Japanese or Chinese Eneloops?

 

[Gauss163]

Were those Japanese or Chinese Eneloops?

The web pages don't say. There "China" or "Chinese" is only mentioned when comparing the Eneloop lite Japan vs. Chinese versions (the Chinese had 12% more capacity but had 38% of the cycle life of the Japanese). So one would think he'd have explicitly mentioned if the others were Chinese. We'll have to wait for AACycler to confirm (he's in this thread).

 

[AA Cycler]

The web pages don't say. There "China" or "Chinese" is only mentioned when comparing the Eneloop lite Japan vs. Chinese versions (the Chinese had 12% more capacity but had 38% of the cycle life of the Japanese). So one would think he'd have explicitly mentioned if the others were Chinese. We'll have to wait for AACycler to confirm (he's in this thread).

Hi, couple of notes

* the eneloops and the eneloop pros I tested were made in Japan for EU market. I don't think you can buy Chinese eneloops in Europe
* 420 vs 630 cycles on standard eneloops - I got 420 cycles with -dV termination and 630 cycles with 0dV termination. Going forward I will use only -dV, because this is how people charge their batteries. I will gradually phase out the 0dV results and replace them with -dV results as I re-test the cells. Eventually all my results will be -dV results, just to keep consistency and to avoid confusion...
* 2100 IEC cycles vs 420 AACycler cycles - you can not really compare these two things. I do full cycles (from 100% SoC to 0% SoC) and the IEC standard does partial cycles. My tests show the worst case scenario, the IEC standard shows the best case scenario. In real life you will be somewhere in between

Cheers,
AA Cycler

 

[Gauss163]

* the eneloops and the eneloop pros I tested were made in Japan for EU market. I don't think you can buy Chinese eneloops in Europe

Thanks for clarifying that. It would be helpful to add that statement to your web pages.

* 420 vs 630 cycles on standard eneloops - I got 420 cycles with -dV termination and 630 cycles with 0dV termination. Going forward I will use only -dV, because this is how people charge their batteries. I will gradually phase out the 0dV results and replace them with -dV results as I re-test the cells. Eventually all my results will be -dV results, just to keep consistency and to avoid confusion...

Ah, so that's what the footnote means (it is not clear since the footnote's '*' doesn't reference anything above). Interesting results.

* 2100 IEC cycles vs 420 AACycler cycles - you can not really compare these two things. I do full cycles (from 100% SoC to 0% SoC) and the IEC standard does partial cycles. My tests show the worst case scenario, the IEC standard shows the best case scenario. In real life you will be somewhere in between

Yes, Panasonic claims "up to 2100 cycles" by "Panasonic internal testing IEC61951-2 (7.5.1.3)", e.g. see p. 25 of the 2017-2018 eneloop catalogue. The referenced IEC endurance test is excerpted on this CPF page. The cycling is done with C/4 charges for 3.17h and C/4 discharges for 2.33h to 1.0V except a couple slow charges (C/10 for 16h) are done to test capacity at every 50th cycle, terminating if a C/5 discharge lasts less than 3hrs, i.e. yields less than 60% of nominal capacity (confirmed by a 2nd such discharge), vs. your stopping at 80% nominal capacity.

So the IEC test will yield much more optimistic results than your cycling tests since IEC uses shallower cycles (60% depth, terminated at 1.0V vs. your 100% terminated at 0.9V) and lower rates (475mAh vs. your 1.0A charge, 0.5A discharge to 0.9V, or was it the old MC3000 setup at 1.5A? Again it would be helpful to say on the web page). Further IEC gains cycles by allowing the cells to degrade further before declaring them "end of life" when the current capacity is 60% (vs. your 80%) of nominal capacity.

In any case, your results will probably better reflect real world cycle life since that does not typically involve shallower cycles such as those used in the IEC testing. This is easier to see with the Pros since they have 4x shorter cycle life (by both IEC & your test) - low enough to be noticeable even to casual users.

 

[Kurt_Woloch]

Sorry for coming a bit late to the party here, but here's some comments from me as well... as written above, the IEC standard always charges the batteries with a fixed amount of charge, which is quite a bit more than what was previously discharged. The C/4 discharges and charges charge the battery with 79% of capacity after taking away 58%, so there's an overcharge of 21% on each cycle. The slow charge which is done prior to the capacity test is C/10 for 16 hours, so it's 160% of capacity, an overcharge of 60%! The thing is, a NiMh battery doesn't need that much of an overcharge in order to be filled up. You can see it on this page by AACycler:

http://aacycler.com/post/nimh-charge-and-energy-efficiency/

As you can see there, up to a point of about 85%, the batteries take up every drop of energy they get (the inefficience actually coming from the voltage difference induced by internal resistance). Only after that the charging energy is being partially converted to heat, but by 115% of capacity, there is not much to be gained by further charging. So a 160% charge goes way beyond that! Compared to that, as also stated on this page, -dV charges the cells with about 106% of what's taken from them, and 0dV charges them with about 104% of the resulting capacity. OK, so the charge currents in these tests were much higher than what the IEC calls for, but I still think the IEC tests are actually harder on the batteries concerning length of charge than AACycler's tests. I think it's mostly the lower end (the end of discharge) where the IEC tests gains its cycles compared with AACycler's tests... but it also could be the speed of charge. But as shown on this page:

http://aacycler.com/post/high-current-vs-low-current/

cutting down the charge rate doesn't result in that many more cycles either.

Just a little bit more to consider...

 

[Gauss163]

[...] I think it's mostly the lower end (the end of discharge) where the IEC tests gains its cycles compared with AACycler's tests... but it also could be the speed of charge.

Yes, that's what I surmised above ("So the IEC test will yield much more optimistic results than your cycling tests since IEC uses shallower cycles ... and lower rates"). Also note that AACyler's tests stop when the cell degrades to 80% capacity but IEC goes further (to 60%), so that too exaggerates cycle life.

It would be interesting to know if - like Li-ion - life increases if the (shallower) cycles are centered around 50% SOC.

In any case it seems that real-word cycles may be much less than Panasonic's claim of 2100 cycles by IEC test (except in the rare? case that usage is close to IEC tests, i.e. shallow 60% cycles and use them till their capacity degrades to 60% vs. 80% of nominal capacity, etc, as above).

 

[Gauss163]

[.. but it also could be the speed of charge. But as shown on this page cutting down the charge rate doesn't result in that many more cycles either.

Keep in mind that those tests were done on the ("worst cycle count") Varta 2100's. Whether or not eneloops behave similarly we can't say for sure till they are tested.

 

[WalkIntoTheLight]

In any case it seems that real-word cycles may be much less than Panasonic's claim of 2100 cycles by IEC test

In the vast majority of use, cells will see nowhere near 2100 cycles, probably nowhere near even 500. Even if the average lifespan of a (regular) Eneloop is 10 years, 500 cycles would mean charging it every single week. 2100 cycles would mean almost every day!

I only have one pair of Eneloop that I might cycle that much. I have a light for general illumination I use every night. In the winter, I recharge the 2xAA cells every day. In summer, maybe every second day. Frankly, most people would see me as insane, so this is extreme use.

I haven't done a capacity test on them, but so far, I haven't noticed any degradation. They probably have about 500 cycles on them. Granted, they're not full cycles. I top them up to 100%, but they're usually only discharged to about 1.30v or a bit less. The cells are 2nd gen Eneloops from 2012, but have only received high usage in the last year or two.

Anyway, I think, (except for nuts like me) that 2100 cycles is moot. 500 is still plenty. And for some of my cells (in remotes), they will probably only see a dozen cycles in their life. It's the low self discharge and shelf life that matters most.

 

[Gauss163]

In the vast majority of use, cells will see nowhere near 2100 cycles, probably nowhere near even 500. Even if the average lifespan of a (regular) Eneloop is 10 years, 500 cycles would mean charging it every single week. 2100 cycles would mean almost every day!

Daily (partial) charges are the norm in some contexts, e.g. in solar-powered devices such as outdoor lights (e.g. Walmart sells them with Westinghouse 18650s).

 

[WalkIntoTheLight]

Daily (partial) charges are the norm in some contexts, e.g. in solar-powered devices such as outdoor lights (e.g. Walmart sells them with Westinghouse 18650s).

Ah, yes, I forgot about those uses. I do have solar garden lights, but don't use Eneloops in them. I'm concerned that the constant trickle-charging would prematurely kill the batteries. Maybe the Eneloop Lite is better suited for that purpose?

 

[batteryfever111]

Today, yet another Eneloop XX cell triggered a blinking warning sign in the charger, and was refused to be charged, and I was looking for some background info on this issue.

Somehow, over the years, all my Eneloop XX and Pro batteries were refused to be charged by the Eneloop chargers form the original ones from the beginning. I only have recent ones functioning.
I don't think I cycled through more than 50 cycles for each of them...

I bought over the years more than 100 eneloop batteries, since the time they first came out, about half of them of them XX and Pro, AA and AAA mixed. At the beginning Sanyo, then Panasonic, and last year, I bought also a lot of Fujitsu rebranded varieties from Nkon.nl (a rechargeable battery specialist in the Netherlands). They ran in lights for biking, led lights for camping/evening reading, long range flash lights for biking, voice recorders, alarm clock, kitchen scale, hair trimmer, you name it. Usually I used the XX / Pro variety where I wanted the extra bit of capacity, like the long range bike light, voice recorder, or the camping lights.

I think I took average care of them, I used the Panasonic BQ-CC65 from the moment it became available, before that, Panasonic BQ-CC17, and recharged the batteries when my devices showed no more power.

The normal eneloop batteries don't seem to trigger such warning signes.

Maybe I am doing something wrong?

I need to buy some new batteries again, and I just wonder shall I still try to use the Pro variety, or just stick to the standard Eneloops.
In the beginning, I can see the benefit of the Pro having more capacity, but it seems that they just die quickly. It's not even the price, but the hassle to discover the batteries don't charge anymore when I would need them.

I went through the forum posts and articles linked.

Any recent views on this topic would be welcome.

 

[ChrisGarrett]

I need to buy some new batteries again, and I just wonder shall I still try to use the Pro variety, or just stick to the standard Eneloops.
In the beginning, I can see the benefit of the Pro having more capacity, but it seems that they just die quickly. It's not even the price, but the hassle to discover the batteries don't charge anymore when I would need them.

I went through the forum posts and articles linked.

Any recent views on this topic would be welcome.

Unless you need the extra 20% capacity here and now, or you don't mind replacing the Hi-Caps every 2-3 years, most of us just use the standard capacity Eneloop type batteries.

They just last so much longer, providing more power over life.

Just the nature of the beast.

I'm not buying Hi-Caps any longer.

Chris

 

[batteryfever111]

Unless you need the extra 20% capacity here and now, or you don't mind replacing the Hi-Caps every 2-3 years, most of us just use the standard capacity Eneloop type batteries.

They just last so much longer, providing more power over life.

Just the nature of the beast.

I'm not buying Hi-Caps any longer.

Chris

Thanks for the affirmation. Then I won't buy any Pro batteries anymore...

Slowly, I was coming to the same conlusion, but I was not sure.

The only scenario I can imagine the 20% benefit is when depleting the batteries in one go, and the 20% makes sense, like photography flashes, radio controlled model cars, electric toys and similar.However, all my such devices now function with built-in LiIon batteries.



I collected all my early batteries, and the conclusion is that even my first buy Eneloops work, and even some of the recent Pro batteries have some trouble.

 

[NiOOH]

The cycle life of Eneloop Pros is much shorter than that of regular Eneloops. As said, if you don't need the extra capacity, just stick with the regulars, or buy IKEA LADDA (rebranded Pros) at 1/3 of the price of the Pros and change them more often.

 

[zeally]

Half the top of one of my Eneloop Pro AAs has come off while inside the flashlight

 

[knucklegary]

Did you go swimming with your flashlight in pocket?
Details and Photos will help.