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Thread: 18650's Care and Maintenance

  1. #91

    Default Re: 18650's Care and Maintenance

    Is it harmful in any way to charge lithium batteries to around 90% such as 4.1V before using? I always feel better under charging them a little to keep the stress levels down, but I don't know for sure if I am doing the right thing.

  2. #92
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    Default Re: 18650's Care and Maintenance

    Hello Klrman,

    If you don't need the capacity your batteries will reward you by giving you improved cycle life. No problem at all.

    Tom
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    Most batteries don't die - they are tortured to near death, then murdered...

  3. #93
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    Default Re: 18650's Care and Maintenance

    It's beneficial - not harmful - to use shallower depth cycles. Further gains can be had by centering cycles around the half-full point (e.g. using 10% - 90% region) since this minimizes the time the cell spends at extreme voltages (where accelerated degradation occurs). See this post (and its links) for much further discussion (including charts and studies). I meant to update some of that info (and simplify it a bit) but - alas - a moderator locked the thread.
    Last edited by Gauss163; 05-18-2018 at 07:14 PM.

  4. #94

    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by SilverFox View Post
    Hello Klrman,

    If you don't need the capacity your batteries will reward you by giving you improved cycle life. No problem at all.

    Tom
    Hello SilverFox,

    Thanks for the reply. Great, I was always hoping it was a good idea to do so, but it feels much better knowing for sure!

  5. #95

    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by Gauss163 View Post
    It's beneficial - not harmful - to use shallower depth cycles. Further gains can be had by centering cycles around the half-full point (e.g. using 10% - 90% region) since this minimizes the time the cell spends at extreme voltages (where accelerated degradation occurs). See this post (and its links) for much further discussion (including charts and studies). I meant to update some of that info (and simplify it a bit) but - alas - a moderator locked the thread.
    Thanks for the info Gauss163, I going to read it all and try and absorb everything. I got my MC3000 recently and will make it work for me as much as possible.

  6. #96

    Default Re: 18650's Care and Maintenance

    Am I correct in assuming, do not use the "Charge Test" on the Opus C3100 for a 18650 battery?

    Thanks

  7. #97
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by ktate749 View Post
    Am I correct in assuming, do not use the "Charge Test" on the Opus C3100 for a 18650 battery?
    Shouldn’t be a problem.

    It’ll just do a charge, discharge, and charge again, giving you information about what capacity you got during discharge.

    Also, see here: http://lygte-info.dk/review/Review%2...V2.1%20UK.html

    (Disclaimer: I don’t currently own this charger)

  8. #98
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by ktate749 View Post
    Am I correct in assuming, do not use the "Charge Test" on the Opus C3100 for a 18650 battery?
    Doing an occasional deep cycle to test capacity isn't going to cause much extra degradation to an optimally managed cell (as long as the capacity tests amount only to a small fraction of the number of equivalent full cycles)

  9. #99

    Default Re: 18650's Care and Maintenance

    Looking at the data sheets for my Panasonic and Sanyo 18650 batteries, they have a value of 3.6V for the "Nominal Voltage". What are they referring to?

    Thank
    ktate749
    Last edited by ktate749; 06-27-2018 at 06:12 PM. Reason: Incorrect punctuation.

  10. #100
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by ktate749 View Post
    Looking at the data sheets for my Panasonic and Sanyo 18650 batteries, they have a value of 3.6V for the "Nominal Voltage". What are they referring to?
    The nominal voltage basically just means that’s roughly the voltage they spend the most time at during discharge. You charge them to 4.2V, but it drops much more quickly down from there, than it does from 3.6V.

    It’s basically just the same as car batteries having a nominal voltage of 12V, yet you charge them to 13.6V or 14.4V, depending.

  11. #101

    Default Re: 18650's Care and Maintenance

    Thanks terjee clears it up.

  12. #102
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    Default Re: 18650's Care and Maintenance

    One cell phone app, on playstore, claims 55% charge does zero damage to cell. But I doubt that. Moreover, isn't there a 3 year shelf lifespan on Lithium Ion Chemicals in the cells?

    Rather than .025% damage at 70%, I would feel better, if the chemist that makes the cells, had a voltage charge to kilo amp hour duty over entire cell life at 1 amp and .350 amp discharge.

    While I am a skeptic as to wisdom of undercharging, I do hope it will make people think about demanding higher cell capacity formats.
    Some people are all lumens and no lux, while others are all lux and no lumens. Some just thank God they have neither.-- All of my lights have throw--some pretty darn far, into the garbage.

  13. #103
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by degarb View Post
    One cell phone app, on playstore, claims 55% charge does zero damage to cell [...]
    Generally using shallower cycles will prolong life, but it certainly won't completely eliminate cycle degradation. Further, to maximize longevity, besides using shallow cycles you should center them around 50% SOC, e.g. if you're going to use cycles of 50% depth then instead of using 0-50% you should center them, i.e. use the 25-75% region. See this post for further details, including graphs of results from studies on such matters.

    Quote Originally Posted by degarb View Post
    Moreover, isn't there a 3 year shelf lifespan on Lithium Ion Chemicals in the cells?
    No, quality cells have much longer life if stored properly. But that may apply to certain installed batteries that are subject to external parasitic loads that could drain them much quicker than self-discharging would. In particular if they drain too low it may no longer be safe to charge them so the BMS will prevent such.
    Last edited by Gauss163; 08-03-2018 at 08:32 PM.

  14. #104
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by djdawg View Post
    What the voltage of two 18650 ..........is it more than 9 volts ?
    LOL.....I know nothin
    I have a Malkoff M-61 drop in that I want to use in a two 18650 batt body ...........can I ??

    Malkoff M61 in a 2-cell body, with two 18650 is a very good idea. You will get extra lumens and great runtime.

    The current will be lower, meaning the cells will be hit less. Generally the more batteries you include, the less each one is drained individually.

    M61 series of course can only take up to 2 Li-Ion cells. Other Malkoff drop-ins can take up to three Li-ion cells. E.g. the Hound Dog.
    ****** Malkoff Devices ****** “Learn to light a candle in the darkest moments of someone’s life. Be the light that helps others see; it is what gives life its deepest significance.” ― Roy T. Bennett, The Light in the Heart

  15. #105
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by Gauss163 View Post
    Generally using shallower cycles will prolong life, but it certainly won't completely eliminate cycle degradation. .

    Interesting point you make. I've always thought the same thing also. I agree.
    On the one hand, you don't want many recharge cycles but it appears that shallow cycles are better than discharing the thing down to 2.5V - beyond empty.
    ****** Malkoff Devices ****** “Learn to light a candle in the darkest moments of someone’s life. Be the light that helps others see; it is what gives life its deepest significance.” ― Roy T. Bennett, The Light in the Heart

  16. #106
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by Illum View Post


    I would prefer to have protected cells in my collection because they protect from overcharge and overdischarge by disconnecting the battery
    Yeah. *But*, one huge problem with protected cells is that they suddenly go out. In a multi-cell configuration but even 1x18650. The circuit kicks in and you are down.

    Now imagine you are in a cave. Or hanging on a mountain. Or in any number of other dangerous situations where suddenly you lose all light. There is no warning period, it goes "Poof".
    Yeah, I realize you have a spare that's 30 seconds away but that can be critical.

    This is one *huge * advantage of running 1x18650 lights off *un* protected cells since you will get a long, gradual decline into the sunset.

    M61 case in point, or 18650 Hound Dog.

    That is one huge advantage of running your lights off 123s, as expensive as that might be. They don't go out in a nanosecond.
    ****** Malkoff Devices ****** “Learn to light a candle in the darkest moments of someone’s life. Be the light that helps others see; it is what gives life its deepest significance.” ― Roy T. Bennett, The Light in the Heart

  17. #107
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by etc View Post
    This is one *huge * advantage of running 1x18650 lights off *un* protected cells since you will get a long, gradual decline into the sunset.
    It depends on the light. Some lights have built-in low-voltage protection. However, those lights usually have a period of step-downs, which give you plenty of warning. For example, Zebralights have a low-voltage protection at 2.7v, but they also step-down well before you're left in the dark. In the case of Zebralight, the built-in LVP would kick in sooner than the 2.5v LVP of a protected cell.

    With most 1x18650 lights that don't use boost drivers, it would be tough to actually be left in the dark with a protected cell. The voltage is just too low for the forward voltage of the LED.

  18. #108
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by WalkIntoTheLight View Post
    It depends on the light. Some lights have built-in low-voltage protection. However, those lights usually have a period of step-downs, which give you plenty of warning. For example, Zebralights have a low-voltage protection at 2.7v, but they also step-down well before you're left in the dark. In the case of Zebralight, the built-in LVP would kick in sooner than the 2.5v LVP of a protected cell.
    None of my Surefires or Surefire clones or Malkoff MDx-series have built-in low-voltage protection. I don't have any Zebralights. Neither do most people that build LEGO assemblies.


    With most 1x18650 lights that don't use boost drivers, it would be tough to actually be left in the dark with a protected cell. The voltage is just too low for the forward voltage of the LED.

    The cell declines to the voltage where the PCB is triggered and you go from xxx lumens to zero lumens in a nanosecond.

    That is how every protected cell has worked with every Lego light with every P60-drop-in module I've had in the last 10 years. This is kind of good as it protected the cell from overdischarge, that's the point of it. It's not so good if you critically need light that very second. Case in point, you are an LEO holding a suspect or suspects in a dark basement. Your lights go out as the cell hits the threshold for cutting out, whatever it is, 2.5V I assume, and that jeopardizes things. I can think of 100 and 1 situations like that.

    Not only does an unprotected cell give you some warning by gradually declining but in an emergency, when you have no spare to reload, you can run it down as low as you have to maintain light. Quality 18650 only cost $7 these days, we are talking 18650 3400 mAh. I remember when they first came out, which seems like yesterday and were close to $20/each.

    Really risking $7 is not that much more expensive than primaries that are 2 bucks a piece retail. Use it several times and you break even.
    ****** Malkoff Devices ****** “Learn to light a candle in the darkest moments of someone’s life. Be the light that helps others see; it is what gives life its deepest significance.” ― Roy T. Bennett, The Light in the Heart

  19. #109
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by etc View Post
    The cell declines to the voltage where the PCB is triggered and you go from xxx lumens to zero lumens in a nanosecond.

    That is how every protected cell has worked with every Lego light with every P60-drop-in module I've had in the last 10 years. This is kind of good as it protected the cell from overdischarge, that's the point of it. It's not so good if you critically need light that very second. Case in point, you are an LEO holding a suspect or suspects in a dark basement. Your lights go out as the cell hits the threshold for cutting out, whatever it is, 2.5V I assume, and that jeopardizes things. I can think of 100 and 1 situations like that.
    My point is that with (non boost-driver) lights, they will already be very dim by the time the protected cell shuts off at 2.5v. For example, an XP-L emitter at 2.5v will be barely lit, if at all. IOW, there's not going to be much practical difference between running the light with a protected or unprotected cell.

    This is completely different if your light has a boost-driver, such as a Zebralight. But, AFAIK, those kinds of lights all have built-in LVP anyway, so it will still be the same regardless of your cell protection.

  20. #110
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    Default Re: 18650's Care and Maintenance

    Quote Originally Posted by etc View Post
    Interesting point you make. I've always thought the same thing also. I agree.
    On the one hand, you don't want many recharge cycles but it appears that shallow cycles are better than discharing the thing down to 2.5V - beyond empty.
    This works because the shallower cycles (centered around 50% SOC) serve to keep the cell away from extreme voltages (which accelerate degradation). Generally to prolong life you want to minimize the amount of lifetime the cell spends at extreme voltages (and temperatures) - both in cycling and storage. Even small changes can yield large improvements because the degradation processes are nonlinear. Follow the link I gave above for further details.
    Last edited by Gauss163; 08-06-2018 at 06:01 PM.

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