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Doug Lerner2 Level 4 Level 4 (1,030 points)

Since getting my new MacBook Pro retina 13" last week I've left it plugged in. Today I need to take it out to a class I'm giving. Last night I unplugged it and put it in a case for this morning. I'm leaving in about 30 minutes.

 

Out of curiousity I woke it up from sleep before and was surprised to see it had dropped to 97% battery overnight. But it was asleep all night. And my energy settings don't have "power nap" turned on while off-battery.

 

So why the drop of 3% overnight? My iPad doesn't do that.

 

Thanks,

 

doug


iMac, Mac OS 9.0.x, iMac (21.5-inch Late 2009, 12 GB)
  • Number88 Level 3 Level 3 (750 points)

    See how it goes after a few battery cycles. They get a bit stronger, it seems.

  • Doug Lerner2 Level 4 Level 4 (1,030 points)

    Just as a followup, I took the MacBook Pro out all day yesterday. During the class I had it on, unplugged, and using it non stop for almost 4 hours. When I got home I did not plug it in. This morning I opened the lid (I left it sleeping) and the charge was at 57%. So I guess that's not bad at all considering how long I used it!

     

    I'm charging it now. When I get to 100% that should be 43% of one charging cycle.

     

    doug

  • JennySHS25 Level 1 Level 1 (30 points)

    the Macbook Pro uses a lithiom-ion battery. These batteries should be charged to 100% and then allowed to drain almost all the way to 0%. Then charge to 100% uninteruped. They need to run full-charge cycles. This will keep your battery in good condition so your mac can last many years. It is understandable that there are times when this is not practicle, but it is a good practice to get in the habit of doing.

  • Doug Lerner2 Level 4 Level 4 (1,030 points)

    JennySHS25 wrote:

     

    the Macbook Pro uses a lithiom-ion battery. These batteries should be charged to 100% and then allowed to drain almost all the way to 0%. Then charge to 100% uninteruped. They need to run full-charge cycles. This will keep your battery in good condition so your mac can last many years. It is understandable that there are times when this is not practicle, but it is a good practice to get in the habit of doing.

    Thanks for your note. But I believe that is actually not the case.

     

    Read, for example, this support article:

     

    http://www.apple.com/batteries/notebooks.html

     

    Note it says:

     

    "A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity."

     

    doug

  • OGELTHORPE Level 7 Level 7 (31,935 points)

    Jenny wrote:  "These batteries should be charged to 100% and then allowed to drain almost all the way to 0%. Then charge to 100% uninteruped."  NOT TRUE.  That is one of the best ways of shortening the life of a lithium ion battery.

     

    I keep my battery connected to AC as much as possible.  At least once per month I will discharge it to the 40% level and then again to AC.  Certainly there are occasions where AC might not be available and do us use it as long as the work requires, but do terminate the session when the MBP gives you the low battery power warning.

     

    For some casual reading, here is some valuable battery information:

     

    http://www.apple.com/support/macbookpro/batteries_power/

     

    http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

     

    http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batterie s

     

    Ciao.

  • PlotinusVeritas Level 6 Level 6 (14,700 points)

     

    JennySHS25 wrote:

     

    the Macbook Pro uses a lithiom-ion battery. These batteries should be charged to 100% and then allowed to drain almost all the way to 0%.

    No, you do NOT EVER want to do that on purpuse, period

     

    Sometimes people get bad advice about their laptop batteries to  "cycle them and drain them low every so often"....this unfortunate "advice" is both common and bad, just dont do that and youll be fine.

     

    This horrible "drain the battery low" advice is somewhat "common" and only exists as a throwback to earlier battery technology,  Lithium cells NEVER like this, and dont do it.

     

     



     

    Keep it plugged in when near a socket so you keep the charging cycles down on your LiPo (lithium polymer) cells / battery, but not plugged in all the time. When not being used for several hours, turn it off.

     

    http://www.apple.com/batteries/notebooks.html

    "Apple does not recommend leaving your portable plugged in all the time."

     

    General rule to remember of Lithium batteries is:

    Never drain them LOW  & dont always/often store them HIGH

     

    While cycle count is commonly seen to be the “miles” on your Lithium Ion pack cell in your Macbook, which they are, this distinction is not a fine line at all, and it is a big misconception to “count charge cycles”

     

    *A person who has, for example, 300 charge cycles on their battery and is recharging at say 50-60% remaining of a 100% charge has better battery usage and care than another person who has 300 charge cycles at say 15% remaining on a 100% charge. 

     

    DoD (depth of discharge) is far more important on the wear and tear on your Macbook battery than any mere charge cycle count.  *There is no set “mile” or wear from a charge cycle in general OR in specific.    As such, contrary to popular conception, counting cycles is not conclusive whatsoever, rather the amount of deep DoD on an averaged scale of its use and charging conditions.

                              (as a very rough analogy would be 20,000 hard miles put on a car vs. 80,000 good miles being something similar)

    *Contrary to some myths out there, there is protection circuitry in your Macbook and therefore you cannot overcharge it when plugged in and already fully charged

     

    *However if you don’t plan on using it for a few hours, turn it OFF (plugged in or otherwise) ..*You don’t want your Macbook both always plugged in AND in sleep mode       (When portable devices are charging and in the on or sleep position, the current that is drawn through the device is called the parasitic load and will alter the dynamics of charge cycle. Battery manufacturers advise against parasitic loading because it induces mini-cycles.)

     

    Keeping batteries connected to a charger ensures that periodic "top-ups" do very minor but continuous damage to individual cells, hence Apples recommendation above:   “Apple does not recommend leaving your portable plugged in all the time”, …this is because “Li-ion degrades fastest at high state-of-charge”.

                        This is also the same reason new Apple notebooks are packaged with 50% charges and not 100%.

     

    LiPo (lithium polymer, same as in your Macbook) batteries do not need conditioning. However...

     

    A lot of battery experts call the use of Lithium cells the "80% Rule" ...meaning use 80% of the charge or so, then recharge them for longer overall life.

     

    Never let your Macbook go into shutdown and safe mode from loss of power, you can corrupt files that way, and the batteries do not like it.

     

    The only quantified abuse seen to Lithium cells are instances when often the cells are repeatedly drained very low…. key word being "often"



    Contrary to what some might say, Lithium batteries have an "ideal" break in period. First ten cycles or so, don't discharge down past 40% of the battery's capacity. Same way you don’t take a new car out and speed and rev the engine hard first 100 or so miles.

     

    Proper treatment is still important. Just because LiPo batteries don’t need conditioning in general, does NOT mean they dont have an ideal use / recharge environment. Anything can be abused even if it doesn’t need conditioning.

     

     

    From Apple on batteries:

    http://support.apple.com/kb/HT1446

    http://www.apple.com/batteries/


     

    Storing your MacBook

    If you are going to store your MacBook away for an extended period of time, keep it in a cool location (room temperature roughly 22° C or about 72° F). Make certain you have at least a 50% charge on the internal battery of your Macbook if you plan on storing it away for a few months; recharge your battery to 50% or so every six months roughly if being stored away. If you live in a humid environment, keep your Macbook stored in its zippered case to prevent infiltration of humidity on the internals of your Macbook which could lead to corrosion.

     

    Considerations:

    Your battery is subject to chemical aging even if not in use. A Lithium battery is aging as soon as its made, regardless.

     

    In a perfect (although impractical) situation, your lithium battery is best idealized swinging back and forth between 20 and 85% SOC (state of charge) roughly.

     

    Further still how you discharge the battery is far more important than how it is either charged or stored short term, and more important long term that cycle counts.

     

    Ultimately counting charge cycles is of little importance.  Abuse in discharging (foremost), charging, and storing the battery and how it affects battery chemistry is important and not the ‘odometer’ reading, or cycle counts on the battery. 

     

    Everything boils down to battery chemistry long term, and not an arbitrary number, or cycle count.

     

    Keep your macbook plugged in when near a socket since in the near end of long-term life, this is beneficial to the battery.

     

     

    Peace

  • Doug Lerner2 Level 4 Level 4 (1,030 points)

    I wonder how important actually turning off the notebook is. That is rather a nuisance to do multiple times a day. It's easy enough to close the lid and let it go into PowerNap. That's the way Apple designed it work, isn't it? I mean, that's the default.

     

    doug

  • PlotinusVeritas Level 6 Level 6 (14,700 points)

    napping is one thing, ON power and napping is another thing

     

     

  • hands4 Level 4 Level 4 (2,215 points)

    Yes.  They are designed to sleep well, wake instantly, and to run weeks or months at a time without rebooting.  They do use some energy to stay alive while spleeping but as you noted that was only 3% overnight.

     

    In rare occasions when you close the lid it could fail to sleep.  If so when you remove it from its case it could be fairly warm or hot.  If this does not happen with your Mac I would not worry about it.  As I said, it is rare.

  • Doug Lerner2 Level 4 Level 4 (1,030 points)

    PlotinusVeritas wrote:

     

    napping is one thing, ON power and napping is another thing

     

     

     

    With the default settings that is true. By default, the energy settings don't do "power napping" when on battery. It only works when connected to power. Of course you can change those settings to allow power napping on battery as well. I assume the defaults are the way they are to prevent excessive battery use while napping on battery.

     

    But are you saying you never let your notebook sleep when connected to power? You always turn it off?

     

    doug

  • PlotinusVeritas Level 6 Level 6 (14,700 points)

    But are you saying you never let your notebook sleep when connected to power?

     

     

    no, I never said that, I said dont do it all the time.

     

    napping on power ALL the time is cause for parasitic charging.  

     

    same reasons your notebook is not a desktop and apple warns:

     

    http://www.apple.com/batteries/notebooks.html

    "Apple does not recommend leaving your portable plugged in all the time."

  • Doug Lerner2 Level 4 Level 4 (1,030 points)

    Just to clarify, the full paragraph there is:

     

    For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. Need a reminder? Add an event to your desktop’s iCal. When your battery no longer holds sufficient charge to meet your needs, you may choose to replace it. If your notebook came with a built-in battery, you should have the battery replaced only by an Apple Authorized Service Provider.

     

     

    I did add an event to remind be to discharge and charge at least once a month. And in practice, it will probably be at least weeklly.

     

    Do you think that is sufficient? Anything wrong with leaving it plugged in for several weeks at a time and doing the recommended charging and discharging?

     

    The battery "juices should keep flowing" if I'm using it instead of a desktop going forward too.

     

    doug

  • PlotinusVeritas Level 6 Level 6 (14,700 points)

    I did add an event to remind be to discharge and charge at least once a month. And in practice, it will probably be at least weeklly.

     

     

    Nope, you dont want to do that on a modern non-user-removable lithium on a Macbook

     

    Theres never ever any reason to do that to any modern lithium, it doesnt do the battery any good whatsoever period.

     

    There is no calibration of current Apple portable Macbooks with built-in batteries.

    http://support.apple.com/kb/ht1490

     

    There is no battery calibration with current Apple portable Macbooks with built-in batteries. Lithium batteries have essentially a 0-‘memory’, and all such calibration involve the estimations fed to the system controller on the SOC (state of charge) of the battery over long periods of time as the battery degrades. The software based battery controller knows the battery's characteristics, or SOC and adjusts itself. This is why there is both no need and purpose to periodically deeply drain your macbook battery, since it doesn’t affect the characteristics of the battery, and further still deep discharges are something you should not do on purpose to any lithium battery.

     

     

    In a perfect (although impractical) situation, your lithium battery is best idealized swinging back and forth between 20 and 85% SOC (state of charge) roughly.

     

     

     


     

     

     

    Youre thinking of OLDER tech batteries  >>

     

    Battery calibration, battery memory, battery overcharging, battery training, …all these concepts are mostly holdovers from much older battery technology, and on older Apple portable Macbooks ranging from early nicads, NiMh and otherwise; and these practices do not apply to your lithium battery and its smart controllers.


    Calibrating the battery on older Apple portable Macbooks with removable batteries.

    http://support.apple.com/kb/PH14087

     

     

     

    Apples own documentation is scant, lacking, and as many users mention, not very straightforward regarding batteries.

     

    Apple uses battery side processors and a special sys. controller  battery management system, but it doesnt protect against some things like

     

    1. often deep discharges

    2. perpetual charge and sleep modes

    3. the mild hazards from gaming and fast discharges on battery (in which case gaming should be done ON power)

     

    etc.

     


  • babowa Level 7 Level 7 (25,655 points)

    Nope, you dont want to do that on a modern non-user-removable lithium on a Macbook

     

    Theres never ever any reason to do that to any modern lithium, it doesnt do the battery any good whatsoever period.

     

    Interesting - so why would Apple recommend you do it?

     

    See this excerpt here:

     

    An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.

     

    From this article:

     

    http://www.apple.com/batteries/notebooks.html

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