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Stop laptop battery from charging beyond certain point

This is a discussion on Stop laptop battery from charging beyond certain point within the Tech Board forums, part of the Community Boards category; Originally Posted by MK27 Malarky. You just make tish up. Have you been TOLD today? Are you really sure you ...

  1. #16
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    Quote Originally Posted by MK27 View Post
    Malarky. You just make tish up.
    Have you been TOLD today?

    Are you really sure you want to argue electronics with an engineering technologist who's twice your age?

    What I am telling you is that the charging circuits now used for these batteries know when to switch from full charge to trickle charge --amps to microamps-- based upon the voltage of the battery. The maximum safe voltage for each type of battery (NI-CaD, NI-MH, etc.) is a known quantity. All one has to do is design the charging circuit to switch at about 95% of that voltage and you have achieved the desired combination of longest per-charge use time without degrading the overall lifetime of the battery.

    Yes, these batteries are rated for 1000 to 5000 deep charges depending on chemistry and manufacturing quality. As you point out that is about 3 years of daily usage... BUT, if you would stay with the original question, the concern was not about running the laptop on batteries every day it was about overcharging the batters because he *DOES NOT* run it on batteries all the time... The correct answer is that when not using the batteries every day, overcharging is no longer a problem... which is what I've been saying.

    It's grade 2 math... how long will his batteries last him if he only runs them down once every 2 weeks? Yep that's right... 21 years.

    Now... WTF is your problem????

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    As a 21 years old electrical engineer with just 2 years of electronics experience, I have already learned that to have a meaningful conversation with someone, you need to actually listen to what they have to say, and not just imagine what they said, and respond to your own imagination.

    I certainly hope I will be more open minded and reasonable when I get 30 years of experience, and be able to talk about electronics and have people agree with me because I am right and not because I have 30 years of experience.
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    Quote Originally Posted by cyberfish View Post
    As a 21 years old electrical engineer with just 2 years of electronics experience, I have already learned that to have a meaningful conversation with someone, you need to actually listen to what they have to say, and not just imagine what they said, and respond to your own imagination.

    I certainly hope I will be more open minded and reasonable when I get 30 years of experience, and be able to talk about electronics and have people agree with me because I am right and not because I have 30 years of experience.
    Open minded is not a problem... make a *logical* or *reasonable* counterpoint and I'm all ears... But you gotta stay on topic if you want to correct me. If you ask "How big is red" and I tell you about 680 nanometeres (which is incorrect, btw, it's actually 650) you're perfectly welcome to explain Red's place in the EM spectrum and use adjacent wavelengths to disprove my statement. In fact I'm likely to thank you for the information. BUT when you pop up and say "It comes in gallons, because I painted my house red" I'm likely to prove a little bit impatient with you... since we aren't talking about house paint... are we?

    Your question was very specific and well stated... To paraphrase: "Will leaving my laptop battery in all the time while I run it almost entirely off the wall adaptor damage the battery?"... the correct answer is "No", because (as we both pointed out) battery chemistry has improved and (as I repeatedly tried to point out) battery charging circuits have improved as well.

    Now along comes the pile-on crew... "I have a friend who's laptop only holds about an hour's charge after discharging and recharging 900 times..." and "I hear this" and "I hear that"... none of which is actually an answer to your question. We are talking about batteries that are essentially in "standby" mode... they're talking about batteries that are in heavy use. They are not even discussing the same topic -- your topic -- and yes I do get just a wee bit impatient with it... *Especially* when it always comes from the same small group of people.

    My friend, I see this kind of crap go on here almost every day. Someone is having trouble with their PC overheating and has to call in a factory technician to fix it. So they read a couple of technical papers on CPU temperature and 2 days later they're 20 times smarter than you are and magically more qualified to talk about it than you... and yes, that has happened right here. Someone has a question about open collector outputs, gets their answer complete with drawings, someone else reads a half page description on a website and voila, they're more informed than you are and of course you're all wet... and that's happened here too.

    These are people who, no matter what, cannot allow someone else to be more correct than they are. They don't speak from experience or training... it comes directly from their own personal insecurity. They HAVE to be right or somehow they're not a worthy person...

    And yes, you are correct to observe that after many years in the industry and on various forums... I've lost all patience for it.

    These people are not about answering your question... they're all about being more correct than the answer given. They are emotionally incapable of allowing someone else to be right, their cosmology of externalized self-esteem (external validation, if you will) demands they argue with whatever answer is given, even if they know they are wrong... even if they are arguing irrelevencies, until their answer is accepted above all others. They're not about helping you... they're all about being told they're a good and worthy person.

    And yes, you are correct to observe that after many years on various forums... I've lost all patience for it.


    Again... for clarity... If your laptop is less than about 10 years old (since the new chemistries came into common use) there is very little risk of damaging your batteries or shortening their lifetime by leaving it plugged into the charger all the time.

    And how do I know this? Well gosh, that would be a combination of experience (maintaining 250 of the things and never having this problem) and knowledge of the circuitry (having both studied it and repaired it)... Not some braggy website put up by a battery supplier who seriously wants more sales.

    Do beware the throngs of "I stayed at Howard Johnson's last night" experts, my friend... they're everywhere.

  4. #19
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    Quote Originally Posted by CommonTater
    Your question was very specific and well stated... To paraphrase: "Will leaving my laptop battery in all the time while I run it almost entirely off the wall adaptor damage the battery?"... the correct answer is "No", because (as we both pointed out) battery chemistry has improved and (as I repeatedly tried to point out) battery charging circuits have improved as well.
    Actually, the question was about how "to stop laptop charging past a certain point" using software

    The underlying assumption behind this question is that "keeping a lithium polymer battery at 100% charge increases rate of aging compared to 40%".

    Your answer is: don't bother, because the underlying assumption is false. This is certainly a valid answer, but...

    The problem is, other than the weight of your personal experience - which conflicts with cyberfish's and MK27's experience - the elaboration that you give does not appear to support your assertion. What you stated about battery chemistry is basically a restating of your assertion without showing why cyberfish, phantomotap and MK27 are wrong. What you stated about battery charging circuits appear to be about the prevention of overcharging, and thus is not related to cyberfish's underlying assumption. Or, maybe it is related, but you neglected to explain: this is why I asked you about your conclusions.

    Unless someone can come up with some real statistics from an unbiased source or some authoritative explanation of whether or not the "nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge" advice is bogus, this seems to be just one person's experience against another's. Yes, 30 years of experience and 250 laptop computers may be impressive, but when there are people whose experience is evidence to the contrary, that should not be ignored either.
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    Quote Originally Posted by laserlight View Post
    Actually, the question was about how "to stop laptop charging past a certain point" using software

    The underlying assumption behind this question is that "keeping a lithium polymer battery at 100% charge increases rate of aging compared to 40%".

    Your answer is: don't bother, because the underlying assumption is false. This is certainly a valid answer, but...
    Incorrect... What I said was that the underlying assumption is of no consequence. That is to say that when you have a laptop computer that's likely to be replaced before battery life ever becomes an issue, there's no point worrying about it...

    Also, there is a certain irrationality to the idea... what's the point of having 2 1/2 or 3 hour battery life if you're only going to charge to 40% essentially limiting yourself to the same per charge time as people with batteries that are at the end of their life cycle. Really, think about what happens when --for some reason-- he needs to unplug and take the computer with him unexpectedly? Now instead of a couple of hours he's got a matter of minutes... rather defeats the whole point... doesn't it?

    The problem is, other than the weight of your personal experience - which conflicts with cyberfish's and MK27's experience
    No, it doesn't... go back and read it again.

    I am responding to the situation where the thing is plugged in 90% of the time... essentially working off wall power with the batteries filling in for power surges (yes they're still connected) and receiving only a trickle charge the rest of the time.

    They were responding from a perspective of computers that are charged every night and used on batteries most of the time. That is an entirely different use of the equipment than Cyberfish was asking about.


    The question: "What is the storage life of a race car" is entirely different than "How often can you drive your race car?"

    I did my very best to keep my response on point... they never even responded to the point.


    - the elaboration that you give does not appear to support your assertion. What you stated about battery chemistry is basically a restating of your assertion without showing why cyberfish, phantomotap and MK27 are wrong. What you stated about battery charging circuits appear to be about the prevention of overcharging, and thus is not related to cyberfish's underlying assumption. Or, maybe it is related, but you neglected to explain: this is why I asked you about your conclusions.
    I don't know how much hardware/electronics skill you have Lase... but it is exactly on point. The underlying assumption was that letting the system self-maintain was somehow going to damage the batteries... and it won't. This is *directly* the result of newer chemistries and improvements in charging circuits.

    Back in the bad old NI-CAD days, the most common charging circuit consisted of a diode and resistor in series. The circuit was "always on" and often operating several volts above the nominal voltage of the batteries... it was typical, for example, to charge a 9 volt battery pack directly from a 12 volt power supply in the device. Nothing prevented overcharging and the batteries did eventually become damaged by it... as in my example of the cordless phone that was always kept in the cradle. This would eventually overcharge the batteries to the point of destruction, leaving the owner with a 4 or 5 minute useful life per-charge.

    Newer chemistries do not exhibit the same characteristic loss of useable life when overcharged. They are more robust and often can deliver far more energy per charge. This is all good as everyone has pointed out...

    Newer charging circuits, largely the result of cheaper chips and surface mount technologies, now allow for some intelligence in the recharging of batteries. The new circuits know the appropriate amount of current to deliver given the voltage of the battery pack... sometimes for each cell in the battery pack. These charging circuits will take the current charge of the battery, it's nominal voltage and sometimes even it's temperature into account when regulating the charging current sent to the battery. They are, in fact fully able to charge the battery in the least destructive way possible. This directly plays to Cyberfish's question because part of the problem with the older systems is that the charger itself was often responsible for destroying the batteries... but that's no longer true.

    Unless someone can come up with some real statistics from an unbiased source or some authoritative explanation of whether or not the "nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge" advice is bogus, this seems to be just one person's experience against another's. Yes, 30 years of experience and 250 laptop computers may be impressive, but when there are people whose experience is evidence to the contrary, that should not be ignored either.
    The problem here is that the "people who's experience is evidence to the contrary"... are not addressing the actual issue... So far we've heard about laptops that are used on batteries every day... nope, not what we're talking about. We've heard about removing the battery cartridge and storing it... also not what's happening here. There has been no statment of "evidence to the contrary" because non of the contradicting replies have addressed the actual scenario in question. So far, with the example of my trusty little netbook, I am the only person who provided any information about computers that are run on power all the time damaging the batteries... everyone else is talking about something else entirely...

    ...and quite frankly it surprises me, Lase, that someone as smart as yourself can't see that.

    So maybe what we're actually discussing here is not the technical aspects of running a laptop --notbook, netbook, whatever-- on power all the time... maybe what we're really discussing here is who you trust and don't trust....

    And FWIW... if he wants to remove the cartridge and store it with a 40% charge (recommended by most manufacturers) all he has to do is start from a fresh charge, run it down to 40% and take out the cartridge. No software required.
    Last edited by CommonTater; 01-10-2012 at 04:35 AM.

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    I have 30 years of experience using batteries without a single clue how they work (aside from the obvious 5th class physics/chemistry). There is one thing I have learned: it's not worth worrying about. Use the battery as the manual tells you to, if the current pack doesn't fit your needs any more for whatever reasons, get a new one.

    The time people have put in this thread so far was probably worth more than a new battery anyway
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    Quote Originally Posted by nvoigt View Post
    I have 30 years of experience using batteries without a single clue how they work (aside from the obvious 5th class physics/chemistry). There is one thing I have learned: it's not worth worrying about. Use the battery as the manual tells you to...
    Which is what I've been saying from the start...

    Non-Issue! Just use the thing.

    It is, however, totally like technical people with limited real world experience to get themselves lost in the minutia like this. When one has little or no practical experience, one is forced into a theoretical playground that often results in wildly screwball ideas, like the one we've seen here.

    Too much therory + Almost no practical experience = "Just enough knowledge to be dangerous".
    Last edited by CommonTater; 01-10-2012 at 06:02 AM.

  8. #23
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    Quote Originally Posted by CommonTater
    Really, think about what happens when --for some reason-- he needs to unplug and take the computer with him unexpectedly? Now instead of a couple of hours he's got a matter of minutes... rather defeats the whole point... doesn't it?
    Yeah, that's the catch with phantomotap's "throwing it on the charger the night before you know you are going to need it" solution: you need to know that you are going to need it.

    That said, it does not defeat the whole point, since I have found that a good reason to have the battery even when you don't need it is when someone accidentally switches off the mains power or trips over your cable or something

    Quote Originally Posted by CommonTater
    I am responding to the situation where the thing is plugged in 90% of the time... essentially working off wall power with the batteries filling in for power surges (yes they're still connected) and receiving only a trickle charge the rest of the time.

    They were responding from a perspective of computers that are charged every night and used on batteries most of the time. That is an entirely different use of the equipment than Cyberfish was asking about.
    I had the impression that they were talking about both the case where the laptop is on mains power with the battery plugged in, and when the battery is left aside for storage. It seems strange otherwise for cyberfish to say that "I'm talking about keeping a lithium polymer battery at 100% charge increases rate of aging compared to 40%" if that pertains only to the latter, since the scenario presented is clearly the former. The way I read post #1 is that cyberfish wanted some kind of software solution to stop the battery from charging beyond 40% when it was in the laptop, with the laptop powered by the mains.

    Quote Originally Posted by CommonTater
    So maybe what we're actually discussing here is not the technical aspects of running a laptop --notbook, netbook, whatever-- on power all the time... maybe what we're really discussing here is who you trust and don't trust....
    I don't trust all of you... you must be trying to get me to ruin my laptop battery so you can raise your stock prices in the laptop battery producing companies

    Quote Originally Posted by CommonTater
    And FWIW... if he wants to remove the cartridge and store it with a 40% charge (recommended by most manufacturers) all he has to do is start from a fresh charge, run it down to 40% and take out the cartridge.
    Okay, this is exactly what phantomotap suggested in post #10, except that it is a non-solution since cyberfish wants the battery in the laptop. That said, you're saying that the 40% thing really applies when the battery is put aside for storage?
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    laserlight is correct. The question is not and has never been "will keeping the laptop plugged in all the time damage the battery". I know it won't.

    The question, as numerous people have understood and tried to explain to you now, is "storing the battery at 100% charge and elevated temperatures in a laptop will significantly increase the rate of the natural aging process, which is well backed by literature. Is there a way to stop the laptop from charging beyond 40%".

    And what's the point of this? I am interning in California for 8 months right now, and will use the laptop as a desktop in these 8 months. Afterwards, I'll go back to school, and use it as a full laptop again. I don't want these months to significantly reduce the life of the battery.

    As for proving it IS a problem to worry about, just look at the table here -
    How to Store Batteries – Battery University
    It agrees with my experience and that of a few others.

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    If you are using the laptop with the batteries installed you are not "storing" the batteries, you are using them. There is a difference between storing, and use. From the link you provided:
    Simple Guidelines for Storing Batteries

    Primary batteries store well. Alkaline and primary lithium batteries can be stored for 10 years with moderate loss capacity.

    Remove battery from the equipment and store in a dry and cool place.

    Jim

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    When laptop is running on mains power, it's not drawing current from the battery. It shouldn't be charging the battery 99% of the time either. In a chemical point of view, it is the same as storing.
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    Quote Originally Posted by cyberfish View Post
    When laptop is running on mains power, it's not drawing current from the battery. It shouldn't be charging the battery 99% of the time either. In a chemical point of view, it is the same as storing.
    The battery is still connected and the machine will draw current from it under several different conditions...
    1) The charger is accidentally disconnected (Lase's trip over the wire scenario).
    2) Intermittant power surges such as harddrive, wireless, video and audio all stating up at once.
    3) When returning from standby mode... see #2.
    4) During brief power outages or "brownouts" when the wall adaptor is working at reduced capacity.
    5) When the wall adaptor overheats and begins reducing voltage.
    and probably several others...

    But you are correct it is not charging continuously... hence my discussion about improved charging circuits. Most moder charge circuits do not enable battery recharge until the battery falls below a certain percentage (90% in most machines) and will then charge it back to it's maximum safe levels.

    The big problem with only charging it to 40% while it's still in the case (if that were possible) is that you are robbing yourself of useable time on the machine should you need to go mobile or should you have a power outage. Essentially you will be degrading your system's performance to that of a system with old batteries... which doesn't make a lot of sense.

    What you can do if you're that concerned about it is to deliberately drain the batteries every couple of weeks... take them right down to nothing and then let the system charge them back up... that is an in-use scenario that will help keep them healthy.



    Juxtapose the following two statements with one another...
    Quote Originally Posted by cyberfish
    The question is not and has never been "will keeping the laptop plugged in all the time damage the battery". I know it won't.
    ...
    And what's the point of this? I am interning in California for 8 months right now, and will use the laptop as a desktop in these 8 months. Afterwards, I'll go back to school, and use it as a full laptop again. I don't want these months to significantly reduce the life of the battery.
    ... now ask yourself what's wrong with this picture?

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    The big problem with only charging it to 40% while it's still in the case (if that were possible) is that you are robbing yourself of useable time on the machine should you need to go mobile or should you have a power outage. Essentially you will be degrading your system's performance to that of a system with old batteries... which doesn't make a lot of sense.
    I know I will not go mobile for the next 8 months. 40% charge will give me about 3 hours run time, which is as long as power outages here have ever been.

    I WILL need to go mobile in 8 months time.

    ... now ask yourself what's wrong with this picture?
    What's wrong with that picture?

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    Quote Originally Posted by cyberfish View Post
    What's wrong with that picture?
    You say you know it won't damage the batteries... but you're worried that it will damage the batteries.

    Make up your mind

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    It won't "damage" batteries, but will accelerate the aging process.

    It's the same as leaving batteries in a 35C car for a long time. It won't damage batteries, because that's still within the storage temperature spec of the battery, but it will make the batteries age faster.

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