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Thread: Want to ask a question to an official ENELOOP technician? Please post them

  1. #1
    Flashaholic* ChibiM's Avatar
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    Default Want to ask a question to an official ENELOOP technician? Please post them

    What would you like to ask an official eneloop technician?
    I'm scheduled on having a meeting with one of the Japanese technicians in 2 weeks from now in Belgium, and if there are any questions you would like to have answered.. please let me know! (if its not answered already on my website).

    I already collected about 30 questions on BLF and Reddit, and from the eneloop101 facebook page, but if there are any other interesting questions, let me know.


    please post them here


    Last edited by ChibiM; 07-13-2018 at 12:46 AM.

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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    A few questions based on recent discussion here:

    (1) Do you know any good methods for eneloops of estimating SOC from resting voltage or simple (pulsed) load tests?

    (2) Do you know of any data that goes beyond the IEC61951-2 (7.5.1.3) cycle life tests reported in the eneloop catalog, i.e that broadens it to show how cycle life varies as one varies the depth of (dis)charge and the (dis)charge rates? (compare discussion here of AACycler's cycle life tests of deeper cycles at higher rates)

    (3) What strategies do you recommend to optimize both cycle and calendar life of eneloops?

    (4) For eneloops that spend most of their life shallowly cycling around the same (high) SOC (e.g. trickle-charged in a solar keyboard), what is the best way to extend their life, e.g. should they occasionally be given deeper cycles by covering the solar panels?

    (5) Perhaps you can obtain a definitive answer as to the exact SOC when shipped from the factory (so we can more accurately estimate self-discharge)

    Also it would be helpful if you could obtain some info about the technician's background since "technican" usually has very broad scope. Here it could range from a battery scientist with deep knowledge of eneloop electrochemistry to a QA engineer with little knowledge of such. To assess the utility of the answers it would be helpful to know where the technician lies along that spectrum.
    Last edited by Gauss163; 06-27-2018 at 09:57 AM.

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    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Thanks for the interesting questions Gauss

    They match a few questions I have on the list, so I'll try to combine them as much as possible.
    I just found it interesting you talked about a solar keyboard, never heard of that.... I heard a trickle charge of 100mAh-200mAh per month is fine.

    I honestly dont know exactly who it is. But at least the person who is hosting the meeting is one of the people who was involved in the "birth of eneloop" in 2005.

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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by ChibiM View Post
    [...] I just found it interesting you talked about a solar keyboard, never heard of that.... I heard a trickle charge of 100mAh-200mAh per month is fine.
    It's not just a question about trickle charging but also about very shallow cycles (here typically near 100% SOC). In this case that high SOC is maintained by solar trickle charging when light is available. That is the only way it can be charged. Typically it will remain near fully charged unless you use it for long periods in the dark.

    There are in fact solar keyboards that use eneloops. A very nice one is the Logitech K760 (which is one of the best Bluetooth keyboards you can find if you prefer quiet scissor keys over loud mechanical keys). Below is a photo showing the eneloops. Logitech claims a full charge will last in darkness for 3 months at 8hrs/day. Kudos to Logitech for nicely leveraging eneloop LSD capabilities (but jeers for not making the batteries user replaceable - it can be done but it's a pain since you have to disassemble the keyboard).

    Last edited by Gauss163; 06-27-2018 at 01:53 PM.

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    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Interesting! First time I hear about those keyboards! Understand your questions.. wrote them down.

    ... anyone else?

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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by Gauss163 View Post
    It's not just a question about trickle charging but also about very shallow cycles (here typically near 100% SOC). In this case that high SOC is maintained by solar trickle charging when light is available. That is the only way it can be charged. Typically it will remain near fully charged unless you use it for long periods in the dark.

    There are in fact solar keyboards that use eneloops. A very nice one is the Logitech K760 (which is one of the best Bluetooth keyboards you can find if you prefer quiet scissor keys over loud mechanical keys). Below is a photo showing the eneloops. Logitech claims a full charge will last in darkness for 3 months at 8hrs/day. Kudos to Logitech for nicely leveraging eneloop LSD capabilities (but jeers for not making the batteries user replaceable - it can be done but it's a pain since you have to disassemble the keyboard).
    It's an interesting question, which I'd like to see answered as well. I suspect Logitech is assuming that very low trickle-charging you'd get from a keyboard solar panel, isn't enough damage Eneloops. So, if they're kept fully charged, and last 10+ years, that's likely longer than the keyboard will last.

    I just measured the current from a small solar panel (but bigger than a keyboard would use) under room illumination, and it's only putting out 1mA. I don't think a keyboard solar panel would do any more than that, even under bright room light. (Maybe under sunlight, though.)

    So, is a trickle charge of 1 milliamp enough to damage Eneloops, long-term? That's about 240mAh per month, assuming 8 hours per day illumination.

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    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Good question.. I'd like to know as well!

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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    I'd also be interested in the longevity of Eneloops which don't get cycled very much. The background for this is the question if it pays off to use them in devices like wall clocks which typically run at least a year on a cell (or in this case, on a charge) or if it would be better to use Alkalines in this case.

    The way my current calculation runs is that it's currently possible to get no-name Alkalines from about 20 cents per cell here in Austria. They may not have the highest possible capacity, but I'm confident that in such low-drain devices you would still get at least 2 Ah out of each of them. Whereas the cheapest standard Eneloops I've seen cost about 3 Euros each, so they would have to replace 15 Alkalines... which in a wall clock which runs for 2 years, for instance, would take 30 years. The question is if the Eneloops would really last that long or if they would get killed by decomposition of chemicals or such during that time.

    This probably isn't easy to determine. One calculation of mine says that the ageing of cells shouldn't be quicker than their self-discharge. Now due to official specifications, the current gen Eneloops keep 75% of their initial charge after 5 years, and 70% after 10 years if I remember right... which means that from the 75% point on, they go down by 1% per year. If they continue to lose 1% per year after that, they should last for 70 more years for a total of 80 years.

    However, another calculation of mine calculates the degradation differently... it assumes one year of degradation to be equal to some amount of cycles whose exact value is yet unknown, but I've read tests of older and newer Eneloop cells, and from them I'd estimate that value to be around 30-35 "typical consumer" cycles per year, out of which there are about 500, so that would give a shelf life of about 16 years. The reason why we don't see any degradation after 10 years then would be that Eneloops tend to keep their capacity pretty much constant through the first half of their life, only falling off later. The "typical consumer use" would be running them dead every time and then recharging them with a quick charger which fully charges them and doesn't let off until they are already pretty hot.

    So the question is which of them could be true... is it 80 years or rather 16 years of shelf life?

    Another question I'd have is about Eneloops going dormant when in low use... which means that the internal resistance rises more and more. This could maybe also apply to a wall clock if the batteries are being charged less than once a year because each charge lasts longer than that... do they get to a point where they need to be cycled pretty quickly multiple times in order to wake up again? This would also lessen their advantage over alkalines since then it's more of a hassle to use them in low-drain applications.

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    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Kurt, by the time I finish the question, the technician probably left the room or fell asleep
    Just joking. But on a serious note, could you please rephrase the question(s) so they would fit within 1 or 2 sentences each? I'm pretty tired and have a hard time trying to rephrase them myself...

    Thanks Kurt!!

  10. #10

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    OK, here are the two actual questions rephrased:

    1. How long is the life expectancy of an Eneloop cell if it's only cycled every two years (i.e. if a charge lasts 2 years)?

    2. If a cycle in an application lasts for two years, should the Eneloop cell then be cycled multiple times after each "real" cycle in order not to fall dormant?

  11. #11
    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by Kurt_Woloch View Post
    OK, here are the two actual questions rephrased:

    1. How long is the life expectancy of an Eneloop cell if it's only cycled every two years (i.e. if a charge lasts 2 years)?

    2. If a cycle in an application lasts for two years, should the Eneloop cell then be cycled multiple times after each "real" cycle in order not to fall dormant?
    Love it!

    Thanks for the questions. Wrote them down
    If anyone wants to drop in their questions here, feel free to do so, before July 13th.

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    Flashaholic* maukka's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Ask him why the Eneloop Pros (AA/AAA) go bad (high internal resistance) with light use (under 100 cycles) in less than five years while normal Eneloops keep on going.

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    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Thanks Maukka for the question. Will write it down!

  14. #14

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    I'm nowhere close to being a battery geek or expert, like many are here, but I do have a few dumb questions:
    • This isn't Eneloop specific, but related and I feel very important as this ultimately effects the life cycles of the cells:
      Panasonic Japan obviously recommends using only the official Panasonic or Sanyo chargers, for liability reasons, among the many reasons. However, they have clearly stated that their own old line of chargers (basically pre-2013) were designed for Evoltas specifically and are "not compatible" with Eneloops (of any generation). Conversely, they also stated that Sanyo's old chargers (pre-2013) were designed for Eneloops specifically and are "not compatible" with Evoltas. No specific technical details were given as to why. No English bulletin or memorandum exists either.
      Refer to: http://jpn.faq.panasonic.com/app/ans...ail/a_id/18096
      http://jpn.faq.panasonic.com/euf/ass...uden_gokan.pdf
      • Now, the actual question: what has Panasonic changed in the newer chargers' firmware programming to allow cross compatibility between two different product lines? Based on the Q&A page outlined above, you can theorize that the termination sequence is different. Also, based on user testing (ie: HKJ), it seems the newer Panasonic chargers also have a significantly different pulsing current profile than the Sanyo ones did (different voltage and amperage). If this question cannot be answered due to "trade secret" reasons, then: Why are the old chargers incompatible with their counterpart products?

    • In regards to the current generation Eneloop Lite (BK-3LCC & BK-4LCC) sold in Europe and the Japan market, Japan made cells (sold before 2016 as since 2016 are China made): Why are the life cycle ratings different between the export version (3000 cycles) and the domestic version (5000 cycles), despite the fact that they were produced in the same factories and carry the same product numbers (albeit with different wrappers)? Is this due to some minor detail differences between the JIS C8708 (2007) and IEC61951-2 testing methods or rating calculations?
    • It was discovered by some users some time ago that the C (BK-2MGC) and D (BK-1MGC) cells, which are now sold in Japan only, contained 4 AAAs and 3 AAs inside, respectively. Does Panasonic have any plans to produce true C and D cells, which will significantly increase capacity and life cycles? This will be extremely useful for lantern use.

  15. #15

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by Kouryu View Post

    • It was discovered by some users some time ago that the C (BK-2MGC) and D (BK-1MGC) cells, which are now sold in Japan only, contained 4 AAAs and 3 AAs inside, respectively. Does Panasonic have any plans to produce true C and D cells, which will significantly increase capacity and life cycles? This will be extremely useful for lantern use.
    Great question, some real deal Eneloop C's and D's would be real nice! I think there would be a good market for these considering most of the big name battery company NiMH C's and D's are cr@p with low capacity non-LSD sub C cells inside a C or D shell.

    A good Eneloop smart charger for C/D cells would be real nice as well.
    Last edited by xxo; 07-10-2018 at 02:24 PM.

  16. #16

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by xxo View Post
    Great question, some real deal Eneloop C's and D's would be real nice! I think there would be a good market for these considering most of the big name battery company NiMH C's and D's are cr@p with low capacity non-LSD sub C cells inside a C or D shell.

    A good Eneloop smart charger for C/D cells would be real nice as well.
    Eneloop C and D cell chargers exist, but not many were sold overseas.... there was the Sanyo NC-TGU01 and now the Panasonic BQ-CC25, which is Japan only... comparing the two, the Sanyo charger is far better despite the lack of ability to charge 9V

  17. #17

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    The NC-TGU01 looks good, I didn't know they made that:

    https://eneloop101.com/charge/eneloop-chargers/#sanyo-chargers-special


  18. #18

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by xxo View Post
    The NC-TGU01 looks good, I didn't know they made that:

    https://eneloop101.com/charge/eneloop-chargers/#sanyo-chargers-special

    I bought one from Singapore a couple of years ago... it works pretty good. I don't use it often as it charges slower than my TGR01 (MQR06), but when I have a bunch of batteries to charge at the same time or I need to charge my Eneloop "C" cells, I use it. I can cheat by using the C/D cell banks to charge AAs for faster rate, if I want to

    A good condition or new one is worth a lot of money these days... it sucks Panasonic killed it off and replaced it with the BQ-CC25 (just a reprogrammed BQ-CC15, to be Eneloop compatible)

  19. #19
    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    @Kouryu,
    thanks for the questions. I copied them! The C D was already on the list!
    Thanks
    Please ask any more questions before Friday 13th

  20. #20

    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Are there ever going to be standard AA eneloops with capacity higher than "min 1900 mAh"?
    Cycle count tests of AA batteries - http://aacycler.com

  21. #21
    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    Quote Originally Posted by AA Cycler View Post
    Are there ever going to be standard AA eneloops with capacity higher than "min 1900 mAh"?
    Thanks AA Cycler, I added that to the list as well!

  22. #22
    Flashaholic* ChibiM's Avatar
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    Default Re: Want to ask a question to an official ENELOOP technician? Please post them

    About 2/3 of all the questions asked and answered... will have to write them all down, and post them on the eneloop101.com site.

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