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Thread: Topping off: A major advantages of rechargeable batts. How often do you top off?

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    Flashaholic* HighlanderNorth's Avatar
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    Question Topping off: A major advantages of rechargeable batts. How often do you top off?

    One of the obvious frustrating issues with disposable primary batteries for the average person, is that they just never know when the batteries in their camera, flaahlight, remote control, computer mouse, etc, will give out and stop working. For most people who frequent this site, that's probably not as big an issue because many/most of us use rechargeable batteries, which we can top off. Some people here will use some primary batteries, but most have battery testers or multimeters that can give us 'some' idea of when the batteries are going to fail.

    However, even a multimeter or battery tester will not give you a definitive answer. They only provide you with enough data to make an educated guess as to when the batteries will go(rechargeable OR primary). But if you use mostly or entirely rechargeable batteries, you can easily wipe out all uncertainty related frustration, by simply tossing them onto a charger...

    But I've read opinions here and there that topping off certain batteries on a regular basis may not be good for those batteries. That would be the case with older batteries that retain a 'memory', but I'm pretty sure there aren't many of them around anymore. I assume there may also be a concern with exceeding a NiMh battery's advertised maximum number of recharge cycles.

    >>Questions:
    👉1). Do you top off your batteries, and how frequently?
    👉2). Will you top off a battery that you know only lost 10 - 50mAh when used last?
    👉3). If topping off leads to exceeding max cycle numbers, what happens to the battery after that number is exceeded?
    👉4). Do you still use disposable primary batteries, and in which applications?
    Last edited by HighlanderNorth; 10-25-2018 at 11:22 AM.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    No emoji in titles please ... it causes database errors
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    This is a rather large topic, but definitely of interest.

    The effects of "topping off" vary by chemistry, as you have noted.

    Unless specifically needing a full charge, I do not routinely max out the SoC ... and, in fact, tend not to completely charge my secondary cells even when drained.

    For most battery chemistry, especially Li-Ion types, time spent at max SoC is one of the most taxing factors in terms of maintaining service life and function.

    As for primaries, I don't use any alkalines any more, but lithium primaries are still useful in certain situations where rechargeables are suboptimal.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Me too. After reading various posts here and some articles on lithium ion battery life, I usually keep my lithiums that arenít being used at 50 to 75% of full capacity. And the ones that are in frequent use I try to charge up to no more than 90% of capacity. Of course, itís hard to be precise in this but I try.
    Last edited by magellan; 10-25-2018 at 06:21 PM.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by magellan View Post
    Me too. After reading various posts here and some articles on lithium ion battery life, I usually keep my lithiums that arenít being used at 50 to 75% of full capacity. And the ones that are in frequent use I try to charge up to no more than 90% of capacity. Of course, itís hard to be precise in this but I try.
    I made it a point to NOT store my hardly ever used LiIon cells at full charge. I would try to keep them at roughly 3.9v to 4.0v. Then, a hurricane or nor'easter would at some point start heading towards the mid atlantic, and I will spend most of an evening running a 4-AA charger and a 4 bay LiIon charger to bring ALL of my LiIon and NiMh batteries to full charge(SOC), just in case the power goes out for an extended period. Keep in mind, I have given away most of the lights I bought between 2011-2013, and sold a few as well. So I'm down to about 6-7 decent quality LED lights, and although I do have batteries to fill all of those lights, I don't have a bunch of spare LiIon or NiMh batteries(maybe 4 extra 18650's, 2 16340's and 1 extra 14500).

    Then the storm blows through, and either the power doesn't go off at all, or it does go off, but for only an hour tops! So I'm stuck with a bunch of fully charged LIion batteries that need to be partially drained again before being stored! So I set them on an end table and let them run on medium for long enough to get them back to 3.9 or 4.0v. That whole recharge, drain process is a PITA.....
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    No emoji in titles please ... it causes database errors
    Sorry about that. I literally just discovered these emojis in my LG V10 a few months ago, and I've used them periodically in posts at various places, but I wasn't aware they caused problems. Maybe they should've included a disclaimer in the emoji list area that they can cause problems at some sites.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Even though it is rough on the cells, I keep my li-ion and NIMH fully charged due to the PITA factor. I don't have a ton of spares, and accept the reduced life with the rationalization that I want the latest technology/chemistry when it comes out every couple of years anyway. I do an approximate FIFO system on my cells to keep use/wear approximately even, and to help me to detect degraded cells as they happen...

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    I never really top off my batteries. Either they are charged or not, Eneloops stay charged for a long time and I'll generally recharge them when they get around 1.26 volts or lower at resting.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by MidnightDistortions View Post
    I never really top off my batteries. Either they are charged or not, Eneloops stay charged for a long time and I'll generally recharge them when they get around 1.26 volts or lower at resting.
    How much of their capacity do they have left if at 1.26v?
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    My only rechargeables are Eneloop AA's and AAA's.

    I ran them all in both high and low discharge applications (in rotation) from full charge to "full" discharge (as in whenever they stopped working for the application) for nearly ten years. They still work, but lately I was noticing them getting a bit warmer on the charger so I decided to retire them on safety grounds alone. I kept (and still do) a few lithium primaries around for the times when I'd actually drained ALL my Eneloops (of a particular size), I think I resorted to that maybe 8 or 10 times over that decade.

    I never cared about maintaining any kind of charging regimen with them - but again I did maintain a rotation regimen in terms of high and low discharge usage.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    I generally top off li-ion before 'needed'.. It's not worth the hassle and record keeping and risk of getting caught partially prepared to have partial charges. I also don't have a lot of li-ion, relative to a lot here I'm sure.

    Eneloops generally get run till they are dead and then fully charged, if they are just sitting not in a device they start fully charged and I leave them alone, though I may check V before putting them into a device in case my rotation let one sit a long time or something...but none of my carry or prep lights are AA...just around the house beaters, kid lights, spare lights, and tons of non-flashlight uses for AA/AAA.
    Last edited by Warp; 11-05-2018 at 08:33 PM.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    .... Unless specifically needing a full charge, I do not routinely max out the SoC ... and, in fact, tend not to completely charge my secondary cells even when drained....
    Quote Originally Posted by Warp View Post
    I generally top off li-ion before 'needed'.. It's not worth the hassle and record keeping and risk of getting caught partially prepared to have partial charges....
    Got a lot of primaries for that ... a lot
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    I top up whenever I've used a light for more than a few minutes. Eneloops get fully recharged. Lithium-ion get charged to about 90%, unless I plan to use the light for a long walk soon, in which case it gets 100% charged.

    Yeah, (for lithium-ion) it's probably better to charge only when it's down to 20%, but the inconvenience of having a light only partially charged ain't worth it.

    If, after a couple of years of use, my lithium-ions are down to 80% of their original capacity, well that's still more than what I'd have in a partially-charged light with a brand-new battery.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    If any are topping off any cell of any chem immediately prior to use, you are abusing your cells, and will suffer reduced cell recharge cycle lifetimes. Same can be said if you pull them from use and immediately place them in a charger. Always rest a cell before and after charging. I know all the flashaholics here rest their cells.

    I have adopted the practice of keeping stored cells SoC at just above half capacity, and the Li-ion cells I use, I try to only charge to 90%. My charger does not have a program function to stop a charge at any chosen SoC, so I have to watch, and just pull the cell off the charger. Every so often, some slip by and get a full terminating charge. If I'm watching charging of NiMH, I pull the cell before termination, but very close to a full charge. Otherwise, my NiMH terminate at full charge.

    Is there a Li-ion charger that allows you to choose an arbitrary voltage value for charge termination?

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by HighlanderNorth View Post
    I made it a point to NOT store my hardly ever used LiIon cells at full charge. I would try to keep them at roughly 3.9v to 4.0v. Then, a hurricane or nor'easter would at some point start heading towards the mid atlantic, and I will spend most of an evening running a 4-AA charger and a 4 bay LiIon charger to bring ALL of my LiIon and NiMh batteries to full charge(SOC), just in case the power goes out for an extended period. Keep in mind, I have given away most of the lights I bought between 2011-2013, and sold a few as well. So I'm down to about 6-7 decent quality LED lights, and although I do have batteries to fill all of those lights, I don't have a bunch of spare LiIon or NiMh batteries(maybe 4 extra 18650's, 2 16340's and 1 extra 14500).

    Then the storm blows through, and either the power doesn't go off at all, or it does go off, but for only an hour tops! So I'm stuck with a bunch of fully charged LIion batteries that need to be partially drained again before being stored! So I set them on an end table and let them run on medium for long enough to get them back to 3.9 or 4.0v. That whole recharge, drain process is a PITA.....
    For all the work you put in to protect your batteries from a slightly faster decline, you could instead spend that time working a part-time job and then use a part of the extra money you earn to buy replacement batteries more frequently. Another advantage would be that you'd always have fully-charged spare batteries on hand.

    I myself keep all of my spare batteries fully charged. When it "feels" like it's times to trade out a battery in one of my flashlights, I use a fully-charged spare and immediately re-charge the traded-out battery. Some of my 18650 batteries are four years old at this point, and I honestly haven't noticed any degradation in performance. Maybe they're lost 10 or 20%, or maybe they've lost 0% - I have no idea. But that's exactly the point. Why work so hard to prevent something you probably won't notice anyway? Just sayin'

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by shira View Post
    For all the work you put in to protect your batteries from a slightly faster decline, you could instead spend that time working a part-time job and then use a part of the extra money you earn to buy replacement batteries more frequently. Another advantage would be that you'd always have fully-charged spare batteries on hand.

    I myself keep all of my spare batteries fully charged. When it "feels" like it's times to trade out a battery in one of my flashlights, I use a fully-charged spare and immediately re-charge the traded-out battery. Some of my 18650 batteries are four years old at this point, and I honestly haven't noticed any degradation in performance. Maybe they're lost 10 or 20%, or maybe they've lost 0% - I have no idea. But that's exactly the point. Why work so hard to prevent something you probably won't notice anyway? Just sayin'
    I'm personally with you on this, Shira. I really do 'care' about my batteries' health - but don't have the head-space or mental energy to manage them to perfection. I'm now relying on the technology in 2018 to 'deal with' my treatment of them, and still have decent enough runtimes for my uses. The perfect battery-conditioning regime would to my mind only truly matter in run-up to an apocalyptic scenario - whereas I am blessed to live somewhere where even the torchaholic's secret wish of regular blackouts, is not the case (prob 5 mins in the last 15 years).

    So I am consciously 'blindly' managing my batteries the way which makes most sense to me - i.e. always topped-up, even after light use. So far, and even after many years of LiIon ownership, that's served well enough (more than, really).
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by shira View Post
    ....Why work so hard to prevent something you probably won't notice anyway? Just sayin'
    I have had LiIon/LiPo batteries for electronics (mobile phones and such) degrade to << 50% function within a couple of years
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    I top off my nimh batteries and put a note when I fully charged the ones I'm not using and every few years I top them all off. I don't top off my lithium ions I do recharge them when drained. I have lithium primaries with a scant few alkalines but rarely use them now since I have duraloops and have replaced a lot of stuff that takes C/D and 9v batteries with AA/AAA and lithium/lithium ion batteries.
    I top off my phone only when I feel I will be nowhere near a way to recharge it for all day otherwise I tend to charge it some in the morning often from 30% to 70% or so which lasts me a few days. I have not let it go below 19% for almost a year now and rarely charge it to 100% usually only when I know I need to get up very early and won't have time to charge it at all I leave it on the charger and wake up with it fully charged.
    The best combination is LSD nimh + energizer lithium primaries for emergency backup.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    I have had LiIon/LiPo batteries for electronics (mobile phones and such) degrade to << 50% function within a couple of years
    I'm skeptical of the battery health for some lithium-ion devices. I have suspicions that it's not just about capacity, but perhaps the battery management system is also using things like internal resistance and perhaps even the age to prevent the system from fully utilizing the battery. This may be valid, because the system wants to maintain safety, but it might not be telling you the whole truth about your internal battery.

    My reason is that I have salvaged 18650 cells from an old HP laptop of mine. At the time, the laptop was giving warnings about replacing the battery and overall laptop run-time wasn't very good. However, when I test the discharge capacity of the cells, they all have about 80%-90% of their stated capacity (2200mAh cells). I think my laptop was lying to me.

    Despite that, I do think those lipo packs used in cell phones probably do age a lot in 2 years. I don't think they're as robust as cylindrical cells, and they're likely abused a lot more since people use their phones all day long. So, 50% after 2 years doesn't sound unreasonable. (Especially if it's an Apple product trying to make you buy a new phone.)

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by WalkIntoTheLight View Post
    I top up whenever I've used a light for more than a few minutes. Eneloops get fully recharged. Lithium-ion get charged to about 90%, unless I plan to use the light for a long walk soon, in which case it gets 100% charged.

    Yeah, (for lithium-ion) it's probably better to charge only when it's down to 20%, but the inconvenience of having a light only partially charged ain't worth it.

    If, after a couple of years of use, my lithium-ions are down to 80% of their original capacity, well that's still more than what I'd have in a partially-charged light with a brand-new battery.
    So much logic and real world practicality.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by WalkIntoTheLight View Post
    I do think those lipo packs used in cell phones probably do age a lot in 2 years. I don't think they're as robust as cylindrical cells, and they're likely abused a lot more since people use their phones all day long. So, 50% after 2 years doesn't sound unreasonable. (Especially if it's an Apple product trying to make you buy a new phone.)
    At the risk of skirting topic, smart cell phones do seem to spontaneously combust more often than other Li-ion powered devices. Apple most certainly does seem to force a hardware update, but I believe they only do this with software updates, feature creep, very often successfully tempting users of older devices to update the software, which invariably slows the device to the point of frustration and uselessness.

    That said, regarding cell performance specifically, I do not believe Apple is intentionally crippling their devices with the intent to force a hardware refresh for its user. Rather, I know Apple realizes just how many of these older devices are out in the wild. I think it is more reasonable to assume that Apple takes a very conservative approach to the batteries in older devices, and the "crippling," the change in cell performance, reduced runtime, is intentional only to make use of an older cell safer. It would be devastating even for Apple if suddenly all the cells in their 4+ year old devices in the wild started to fail, en mass. Apple is being smart here, not to force new hardware purchases, but to prevent fires, injuries, deaths and expensive lawsuits. They are taking the correct approach to the real danger inherent in Li-ion cell use, and because of their philosophy, removing any responsibility from the user as far as how to properly care for the cell. IOW, this is not sabotage, but instead conservatism to prevent as long as possible cell failure, even if a particular cell in a particular device is in good shape, there are millions of these things out there, and profiles must be applied as simply as possible, thus across all older devices, just to make as certain as possible no one gets -- and it does happen anyway! I cannot say the same for other smart phone manufacturers that definitely seem to push the envelop, regarding cell performance, and therefor safety.

    So I think our paranoia is only half justified, there is definitely a rational benevolent method behind Apple's treatment of older Li-ion cells: preventing never ending legal bills, which does benefit our health.
    Last edited by night.hoodie; 11-07-2018 at 06:18 AM.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    My point was that, since using a more active battery management style, I have found noticeable real-world benefits.

    This has been more evident to me with LiPo in (yes, integrated and monitored, but also more heavily used) electronics, on the order of a ~ 50+ % performance differential, over the course of as little as ~ 2 years.

    With a timed charger, it is not too inconvenient to avoid charging over, say, 70%

    Whether or not this is "relevant" or "significant" or "worth" the effort, may vary. I know some upgrade their mobile phones every year, while others keep using these devices for much longer.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    I know some upgrade their mobile phones every year, while others keep using these devices for much longer.
    iPhone 4 here since Summer 2010, original battery.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by night.hoodie View Post
    iPhone 4 here since Summer 2010, original battery.
    Do you "actively manage" your charging, and how much (if any) noticable decrease in battery performance over ~ 8 years ?
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    One of the great things about flashlights that take removable batteries, is you don't have to handicap their available performance for years and years, you can just spend a few bucks on a new battery after several years if need be.

    Same thing for a lot of older non-Apple phones.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    Do you "actively manage" your charging, and how much (if any) noticable decrease in battery performance over ~ 8 years ?
    No, I really haven't, I've been bad. I only started learning about Li-ion cells years later. Battery performance in it is abysmal, but consistent, so I know what to expect, and knowing remaining capacity is not something I must look at the battery indicator for, I just know... depending on what I am doing, which is almost never talking on it or calling, that I need to plug it in and charge it, many times a day under heavy use. I can still watch a full length movie streamed over wifi from a local media server, or from a local movie synced to play it on an external display. That's about the limits of the capacity. Its just fine as an iPod still, as the screen doesn't get used much while listening in a car, where I usually, but not always, simultaneously charge it. Also, I'll turn off wifi, or go with airport mode. I keep meaning to get the battery replaced... but these things sometimes sell on eBay for $18. I mean the whole device, not just the battery. $50 is a median price for it, so replacing the battery isn't happening.
    Last edited by night.hoodie; 11-07-2018 at 02:48 PM.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by Warp View Post
    One of the great things about flashlights that take removable batteries, is you don't have to handicap their available performance for years and years, you can just spend a few bucks on a new battery after several years if need be....
    Clearly there are differing approaches to this issue, as would be expected, but personally I don't consider using rechargeable cells at submaximal SoC to be a "handicap"

    I can, and sometimes do, quickly and easily charge these up fully when needed.

    But leaving LiIon cells for extended duration at maximal charge will lead to irreversible degradation in performance.

    I agree that whether that is considered relevant or not, apart from or despite the cost(s) of replacement, depends on the specific circumstances and situation.

    Also of note, given continued improvement in battery tech over a several year time frame, newer cells may have substantially better performance than the cells they are replacing would have had even when new.
    Last edited by archimedes; 11-07-2018 at 05:08 PM.
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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    A lot of high-powered lights, especially in the "budget" category, use FET drivers to achieve maximum brightness out of the LED. In those lights, if you want the high output, you have to use fully-charged batteries. Performance from a FET driver really sucks when it's down to about 50% charged. (Still better than a linear driver, but not as good as what you expect from a FET driver.)

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by archimedes View Post
    For most battery chemistry, especially Li-Ion types, time spent at max SoC is one of the most taxing factors in terms of maintaining service life and function.
    Yes! Time at max soc is the killer, mostly from lithium plating of the positive cathode. Inorganic materials also clog the pores of the SEI layer too. So spending the least amount of time to get the job done is the keyword.

    Thing is, many chargers are not "adaptive", that is they treat old cells just like new ones and can add to the problem.

    Ie, a charger may spend too much *time* trying to bring an old cell to 4.2v (as an example, the whole voltage thing has been covered elsewhere here), and if using a typical cc/cv algo, spend a lot of time in absorb at that voltage.

    But, due to use / aging, an adaptive approach like bringing the cell to only 4.1v and allowing for absorb to take place might be the better option timewise. Perhaps cut that absorb current value in half as compared to new as the signal to stop the charge.

    Obviously this means programmable chargers, and the time and energy willing to go that far, rather than just simply replace a consumable item a little more often.

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    Default Re: Topping off: A major advantages of rechargeable batts. How often do you top off?

    Quote Originally Posted by IonicBond View Post
    Yes! Time at max soc is the killer, mostly from lithium plating of the positive cathode [...]

    Lithium plating is not due to high SOC. Rather it is primarily due to charging at too high current (esp. at lower temps). High SOC greatly accelerates other degradation processes, e.g. see the list below, summarized from this post.

    Anode degradation effects due to high SOC
    Intercalation of solvent / peeling of graphite/cracking ( loss of capacity [loss of active material / lithium])
    Dissolution of electrolyte (cathodic oxidation / anodic reduction) / dissolution of binder ( loss of capacity / power capability)
    Decrease of active surface (continuous growth of SEI) ( growth of impedance, loss of power capability)

    Cathode degradation effects due to high SOC
    Migration of soluble species ( loss of capacity by film formation on anode)
    Electrolyte decomposition ( loss of power capability)
    Last edited by Gauss163; 11-12-2018 at 03:09 PM.

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