How to set NOT to recharge battery unless <40% full?

Discussion in 'MacBook Pro' started by tennis.music, Nov 15, 2010.

  1. tennis.music macrumors newbie

    Joined:
    Nov 10, 2006
    #1
    If I plug in the power cord, Snow Leopard will recharge the battery if it's bellow 95% full. But this is not healthy for the battery. I basically use my MBP every day, and more than 10 hours a day, except for sleeping or traveling to work. Each time I will use the power cord. This means, the battery is always 95%-100% charged, never get under that, and this is very bad for the battery. It's estimated that only 80% capacity remains after 1 year if I keep using in this way, but it would be 96% if I keep it at 40% charged, at temperature 25 degree.

    Don't ask me to unplug the AC, because straining and charging it everyday is not good to the battery too.

    Don't ask me to calibrate the battery once in a while, that's a different issue, I want to keep the battery in low charged level.

    Don't ask me to take out the battery and store it in the refrigerator, it's a unibody MBP and and I think there should be a better solution.

    Here is what I want to do: adjust the computer's recharge threshold from 95% to 40%, by this way I can keep the battery in a low charged level for a long time and I don't need to remember anything, but I found no way to do so?

    Any idea how to do it?

    Thanks
     
  2. GimmeSlack12 macrumors 603

    GimmeSlack12

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    Apr 29, 2005
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    San Francisco
    #2
    To answer your question: I don't know. If the battery starts charging once it hits 39% then once it hits 41% will it stop charging? This, naturally, would be a problem for the software maker of this vaporware.

    Otherwise, why are you so sure that charging the battery a lot is so bad for it? Why not just leave it plugged in for the first couple hours of your "10 hour day" and then unplug it for the rest of the day?
     
  3. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #3
    Can't be done, you cannot alter how the latop charges the battery. If it senses the battery is not at 100%, it will start charging.

    You're only option is not plug it in. yes I read your post asking people not to state that, but you have not other alternative AFAIK
     
  4. mrsir2009 macrumors 604

    mrsir2009

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    Sep 17, 2009
    Location:
    Melbourne, Australia
    #4
    Sorry, but I don't think you can alter that. Its a core system function thats built into the SMC or something...
     
  5. croooow macrumors 65816

    croooow

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    Jul 16, 2004
    #5
    I don't think I understand why unplugging it (until the battery reaches 40%) would strain the battery. Could you elaborate? I will be getting my first portable Mac soon so I am looking for all the tips I can find.

    Thanks
     
  6. toxic macrumors 68000

    Joined:
    Nov 9, 2008
    #6
    leaving it plugged in is not bad for the battery unless it's for very long periods of time. just unplug it and use the battery for a few hours once every week or two.

    its quite ironic that you're so concerned with battery life when you don't even use the battery.
     
  7. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #7
    You're taking the wrong approach. It's perfectly fine to run it with the AC plugged in. It's just not good to do so ALL the time. Run it on battery for a few hours every 2 or 3 days (not every day), and you'll be fine.

    This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ
    It doesn't. The OP is misinformed.
     
  8. ryannazaretian macrumors 6502a

    ryannazaretian

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    Sep 21, 2008
    Location:
    Mississippi
    #8
    The point of it is to keep the battery charge around 40% if not in use. With all other portables, you can discharge to about 40% and remove the battery.

    40% is the magic charge to keep the battery above the minimum voltage, and to lengthen the life of the battery. Keeping your battery near full all the time does harm the battery.

    What the OP wants to do is keep the charge around 40% unless he actually wants to charge the battery for use later on. No charging, no discharging. Make the battery act like it's not even in the computer.

    He's not misinformed at all. This has been a common tid-bit of information for many years, and things have not changed.

    I think it's a totally legitimate feature request, but in Apple's eyes, this would create too much complication and would confuse their poor delicate customers. (Same reason we only have high performance option for video card... the Intel card struggles doing simple stuff such as full screen flash).

    http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
     
  9. Corndog5595 macrumors 65816

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    Jul 16, 2010
  10. ryannazaretian macrumors 6502a

    ryannazaretian

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    Mississippi
    #10
    No
     
  11. Corndog5595 macrumors 65816

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    Jul 16, 2010
    #11
    What happens when you remove the battery completely?
     
  12. RKpro macrumors 6502

    Joined:
    Oct 27, 2008
    #12
    Charging is not controlled by os.

    Apple computers actually manage batteries well. On my previous non-apple laptops, if I were to plug an already charged laptop into the wall, it would start charging the battery for a few minutes before realizing that the battery was already full. I would use my laptops mostly plugged in at a desk, so I suspect this overcharging contributed to poor battery life, after about a year the battery would lose more than half of the capacity.

    My macbook pro is over 2 years old and still has 92% health, and I didn't have to go out of my way to keep it healthy. I think it's because of that mechanism that doesn't charge the battery unless it needs a charge.
     
  13. toxic macrumors 68000

    Joined:
    Nov 9, 2008
    #13
    the 40% is for long-term storage in a controlled environment. the inside of a laptop is not a controlled environment. the battery will deteriorate, be it from use, non-use, or heat.

    and just because it deteriorates the battery doesn't make it unhealthy. is driving a car unhealthy?
     
  14. GGJstudios, Nov 15, 2010
    Last edited: Nov 15, 2010

    GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #14
    Yes, the OP is misinformed, as are you. The 40-50% you're referring to is for long-term storage of a battery that is not in the computer. It is not appropriate or achievable for a battery that's being used in the computer, such as the OP's situation. You should also be aware that the information on batteryuniversity.com is generic and doesn't specifically apply to the particular batteries used in Apple portables. For accurate information, look to Apple's site for information on Apple-specific batteries.
    If you only do one cycle per month, you will shorten your battery life. Read the FAQ I posted a link to.
    Read the FAQ link I posted. It's not advisable to run on AC power without the battery.
     
  15. applepearpp macrumors regular

    Joined:
    Oct 19, 2010
    #15
    use your laptop on the battery, then when it's around 40, take the battery out and put it aside. shrug.
     
  16. GGJstudios macrumors Westmere

    GGJstudios

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    May 16, 2008
    #16
    NOT recommended. Read the FAQ I posted.
     
  17. ryannazaretian macrumors 6502a

    ryannazaretian

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    Sep 21, 2008
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    Mississippi
    #17
    I do not believe the OP or I are misinformed, and you have not proven otherwise either.

    OP said:
    GGJStudios said:
    So, the OP is using it all the time using the power cord. He has no need to run it from the battery.

    The OP does not use his battery, therefore, his battery would last longer if stored at 40% or as you said 50%. Since you technically can't store these batteries (if it has the built in battery, and because running it without the battery lowers the performance), there could be a built in mechanism to hold the battery at an optimal storage level and to perform an automatic calibration on it whenever necessary. You know... make a smart battery system. This could be done with a simple firmware upgrade and some incorporation into the Energy Saver preference pane.

    From my interpretation, the OP uses a laptop so he can bring his work home with him and does not use the battery at all. Yes, the battery is inside the laptop, but he's not using it. The OP does want to store it for long term, but doesn't want to remove it due to performance issues, or because it may be built in.

    And sorry to break it to you... but the batteries inside of Apple computers are not any different from any other notebook PC (Lithium Polymer has the same properties as Lithium Ion as far as lifespan and how to treat them). The recommendations between batteryuniversity.com and Apple may be slightly different, but the technology behind the battery is the same.

    Plus, are you really going to argue over whether to store it at 40% or 50%? I mean, really?!?

    Sorry if this is confusing at all. I've gone back and changed everything quite a bit.
     
  18. Bernard SG macrumors 65816

    Bernard SG

    Joined:
    Jul 3, 2010
    #18
    ^As GGJStudios already mentioned, storage refers to long periods when the laptop is not used at all and switched-off.
    Please read the pages that GGJ linked. Everything you need to know is there.
     
  19. TuffLuffJimmy macrumors G3

    TuffLuffJimmy

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    Apr 6, 2007
    Location:
    Portland, OR
    #19
    There's quite a bit of misinformation in this thread. I would venture to guess the OP's request would be very difficult to fulfill (although I have no evidence of this). I believe this because of how locked down Apple is about their software and hardware integration, so there's very little public documentation of how their devices work.

    Anyway, it IS possible to make it so the battery is only charged once it hits 40% rather than the OS default of 95%. Maybe some smart developer could make an application to adjust this.


    ALSO: I'm interested in knowing how the OP came up with his or her battery life stats.
     
  20. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #20
    Please take the time to read the FAQ I posted. If you would do so, you would know that you shouldn't run on AC power all the time and you also shouldn't run without the battery, as performance may suffer. The OP DOES need to run with the battery installed, and DOES need to run on battery power every few days, to keep electrons moving.
    Mac OS X DOES use the battery when the system demands more power than the A/C adaptor alone can provide.
    This is not feasible, since the MBP needs the battery for optimum performance. Trying to circumvent Apple's power design is not a viable solution. Just use it as it's designed and recommended and it will work just fine. There's no need to attempt to reinvent the battery/charging/power system that Apple designed.
    Mac OS X is, indeed, using the battery when it needs to. The problem is simply that the OP is running on AC power too much.
    The general concepts are the same, but the specific recommendations for optimum use are more accurate coming from Apple, who supplies the batteries. batteryuniversity.com isn't going to replace a faulty battery. Apple will.
    This is exactly why it's more prudent to follow Apple's recommendations, rather than batteryuniversity.com or some poster in a forum. Apple has far more information about their products than anyone else does.
    I'm not arguing. The 50% figure came from Apple, not me. If you want to challenge it, talk to Apple.
     
  21. Bernard SG macrumors 65816

    Bernard SG

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    Jul 3, 2010
    #21
    Oh noes... :rolleyes:

    I'm very doubtful that it is possible. Battery charging is not managed by the OS. It's controlled by a small processor attached to the battery itself.
    If battery-charging was managed by OS, you couldn't charge your battery unless your lappie is switched on and running. :cool:
     
  22. ryannazaretian, Nov 15, 2010
    Last edited: Nov 15, 2010

    ryannazaretian macrumors 6502a

    ryannazaretian

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    Location:
    Mississippi
    #22
    I've read it many times... and I know that you're not to keep the battery fully charged at all times. So does the OP. He's trying to circumvent that.

    I also know this... it's kind of a design flaw if you ask me...

    Here's where we have a big problem. The OP does not need the battery. If he could, he would use it without the battery, but complications described above interfere with this method.

    That's the problem with Apple's power design. It shouldn't have to run off of the battery at all while plugged in. Apple currently does not even sell a portable computer with a removable battery. While I love the 8 hour battery life... it does kind of suck that you cannot remove it for many reasons.

    I'm not wanting to challenge anything... it's just kind of stupid that you're trying to argue that I should keep a battery charged at 50% per Apple's recommendation rather than 40% or any other value around there. In the end, it's not going to make a difference between 40% and 50%. Apple is not going to refuse to replace a battery because you stored it at 40, 41, 42, 43, 44%.... and not the 50% they recommended. They're going to replace it if it falls under the warranty.

    So now that we're almost completely off topic... lets try to get back on.

    _____________________________________________________________________________

    tennis.music, there is currently no way to achieve what you would like.

    If your laptop has a removable battery, then that's the only way to keep it at a partial charge. As everyone else has said, it will reduce your performance. If you're not a power user, then you will probably not even see the performance difference (plus it makes the laptop lighter for transportation :)). Just try to refrain from playing with the fun MagSafe connector.

    If you have a built in battery, then you're out of luck. Use the battery, as recommended, every few days. You shouldn't have to worry about calibration if you don't care about the battery. It's just extra cycles on your battery, and lithium polymer batteries have no memory effect.

    You can always try to give Apple some feedback at http://www.apple.com/feedback/macbookpro.html
     
  23. TuffLuffJimmy macrumors G3

    TuffLuffJimmy

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    Apr 6, 2007
    Location:
    Portland, OR
    #23
    That was rude and unwarranted. I didn't say "I hate Apple because of their locked down style!" it's no secret that Apple is more vertically integrated than other technology companies.


    And Apple would be stupid to not allow for the modification of the battery firmware through software updates. Therefore it is modifiable. QED
     
  24. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #24
    That's the OP's problem. He shouldn't be trying to circumvent it.
    ....in your opinion. I'll trust Apple's opinion, since their team is obviously better qualified and better informed as to why they choose the technology and methodology that they do.
    Again, your uninformed opinion.
    I didn't argue anything. I simply quoted Apple. What you read were Apple's words, not mine. Please try to read and comprehend before you accuse.
     
  25. ryannazaretian macrumors 6502a

    ryannazaretian

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    Sep 21, 2008
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    Mississippi
    #25
    He's trying to make his battery last longer, but has no need to use the battery...

    It's because the 85W power adapter cannot handle the higher loads. Apple could sell a 100W or higher power adapter for people that want to use their machine to full performance with the battery removed. Simply a supply vs. demand problem.

    Uninformed how? If it's plugged in, I don't want it to run it off the battery. I want to run it off the battery only if it's unplugged. Seems like a simple concept to me...

    You challenged my 40% recommendation. Apple didn't post that on this thread, you did. You could have left that alone, but you didn't. You and I both know that there is no real world difference between storing the battery at 40% and 50%.
     

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