charging Strategy ?

Discussion in 'iPad' started by matelot, Nov 4, 2011.

  1. matelot macrumors regular

    Joined:
    Aug 16, 2010
    Location:
    NY
    #1
    what exactly is the recommended "charging strategy" ? (iPad2)

    should I do it like I do w/ MBA -
    topping-off mode: plug in whenever available
    or
    Full-cycle drain-and-refill : use to low level (like 10%) then re-charge full
     
  2. poloponies macrumors 68030

    Joined:
    May 3, 2010
    #2
    There are easily a hundred posts on this topic and Apple has a battery info page:

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

    Charge it whenever you want to charge it and discharge fully once a month.
     
  3. NashMan2 macrumors regular

    Joined:
    Mar 27, 2009
    #3
    Please don't give me a hard time but....when you say fully discharge - you mean 0% charge? It won't damage the device?
     
  4. bufffilm macrumors 68040

    bufffilm

    Joined:
    May 3, 2011
    #4
    if you want to really know know the best charging/use strategy, look thru one of my older posts on a related thread where someone else posed the same question. the lithium-ion batteries in the ipad are similar to the ones in the later generation laptops. [i happen to have a lot of experience and knowledge about laptops because collecting and using them has been an on-off hobby of mine's ]

    two thing that will negatively affect the long-term storage capability of the battery are constant topping-off and frequent deep discharging. apple's recommendation to do one complete discharge a month is also an poor panacea because it's a "one size fit all rule" and it does't take into account how often a user recharges their tablet and at what level the battery was at when the charging cycle was started. all this stuff is related and can make a difference.

    there was a recent thread about someone who keeps their ipad plugged in 90% of the time and it was sad how uninformed the repies were on that thread - bad advice and oversimplification all around, basically the blind leading the blind.
     
  5. poloponies macrumors 68030

    Joined:
    May 3, 2010
    #5
    Not intending to give you a hard time, but I linked to Apple's own information. The battery doesn't care how/when/how often you charge it. Their recommendation (clearly stated on the link) is to take it to 100% and then let it drop to 0% through normal usage about once a month. the rest of the time you can leave it plugged in constantly, charge it when it drops to zero or anything in between. It just doesn't matter.
     
  6. bufffilm macrumors 68040

    bufffilm

    Joined:
    May 3, 2011
    #6
    you really need to stop saying it just doesn't matter. that would be totally wrong.

    but hey, do what you wanna do. the adage "You can lead a horse to water, but you can't make him drink" comes to mind.

    not going to say any more on the matter.
     
  7. Thetonyk123 macrumors 68000

    Thetonyk123

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    Earth
  8. Pete the Geek macrumors regular

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    Mar 5, 2011
    Location:
    Sioux Lookout
    #8
    I charge all my devices (iPads, iPods) at night when I can (so a top-up). The point of these gadgets is convenience and for that reason I prefer to have them always as charged as possible. When I can't charge them for some reason (e.g. travel), I've had no problem going 2 full days (thought I'd skip game playing on the iPad on that second day).

    As the previous link shows, Apple says topping up is OK.
     
  9. paulrbeers macrumors 68040

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    Dec 17, 2009
    #9

    I'm gonna trust Apple and all their highly paid engineers that know their devices inside and out over a guy on a forum.....
     
  10. TLewis macrumors 65816

    Joined:
    Sep 19, 2007
    Location:
    left coast, US
    #10
    (Sigh, this has been beat to death, but I'll bite again, since it's been a while for me. :rolleyes: )

    First of all, Apple's recommendations are good. However, there's actual science behind their recommendations, and the battery does care how it's charged and discharged. It does matter.

    (Oooh, scary hard science! Run away! :rolleyes: )

    If you want to maximize lithium-ion battery longevity (how many years/months the battery lasts), you should charge it by topping it off as often as possible. Lithium-ion batteries like top-off charges. Deep discharges (going to "zero") shorten the overall battery lifetime. However, in order to keep the battery meter calibrated (to give you an accurate reading of how much battery you have left), you need to calibrate the battery meter by running the battery down as low as possible (down to zero if possible). Apple's recommendation of doing this once a month or so is an engineering tradeoff: in order to get an accurate battery meter, you're trading off a tiny amount of battery overall lifetime. By doing this infrequently (e.g., once a month, per Apple's recommendations), the decrease in overall battery lifetime should be insignificant. However, for example, if you deep discharged the battery daily, it wouldn't surprise me if your iPad's battery didn't last anywhere near as long as someone else's, who didn't do daily deep discharges.

    (Technical nit, for those anal people: when a consumer electronics battery meter reads "zero", it's not really zero -- the battery still has a small amount of power left. This is done to protect the battery, as it would be damaged if the charge gets below some level. So, when you discharge the battery until the iPad dies, you're not really damaging the battery, except in the sense that you're shortening the overall longevity, as mentioned above.)

    If you want more technical information, go here: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

    Interesting tidbit, from the above url: if you assume that a battery is "worn out" when it has only 70% of its capacity when new, an example battery, that is always fully discharged before being recharged, lasted for 500 chargings. An example battery that was only 10% discharged before recharging lasted for 4700 chargings.

    Also, lithium-ion batteries don't like heat: heat, like deep discharges, shortens the overall battery lifetime. Don't leave your iPad in a hot car or similar place.
     
  11. matelot thread starter macrumors regular

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    Aug 16, 2010
    Location:
    NY
    #11
    I searched your past comments and haha you sure post a lot :eek:.
    After pages of search results I only found this one
     
  12. takeshi74 macrumors 601

    Joined:
    Feb 9, 2011
    #12
    If the horse can reason and you're leading it with nothing but anecdotal evidence then the horse is fully justified in taking your lead as dubious.
     
  13. filmbuff macrumors 6502a

    filmbuff

    Joined:
    Jan 5, 2011
    #13
    Keep in mind, the iPad has a "smart" battery. Unlike older laptop batteries it won't easily lose charge from too many top-offs (or deep cycles, whichever it is). Heat also shouldn't be an issue because the iPad doesn't generate much heat while it is running.
     
  14. bufffilm macrumors 68040

    bufffilm

    Joined:
    May 3, 2011
    #14
    annecdotal?...hardly. i'm an IT technical person...i always research anything and do it in depth. i've read pretty much everything out there on the internet when it comes to batteries and how to care for them, including the website that TLewis quoted. and i did read apple's own information even before i got my ipad in case there was something different about their power cells.

    also there is a distinction between topping-off and leaving it plugged in constantly. btw, the ipad is less susceptible to battery 'damage' that constant charging does because of the low voltages involved (something that is mentioned in that article btw), but if you leave a laptop battery constantly plugged in and you'll see faster battery deterioration. (i've seen this myself when i used to do desktop support and if you ask experienced support guys that, they'll tell you the same.)

    apple purposely does not go into much technical detail about battery care because that's how they operate - it's easier to just tell users to do a full discharge 1x a month because it minimizes the amount of support they need to do answering questions, etc. but it's clearly documented that regular deep discharging is not good and they don't disclose this to their customers. and for those who are encamped in the always 'top-off' camp, there's a reason why the ipad batteries go from fast charging mode to trickle mode after they reach 80% charge.

    all of this is arguably moot in a way because their cells are rated to 1000 charges and what's the majority of users who are going to keep their ipads for 3+ years?

    [well me probably...i still have laptops from 7+ yrs ago still going strong.]
     
  15. TLewis macrumors 65816

    Joined:
    Sep 19, 2007
    Location:
    left coast, US
    #15
    I think you've misdiagnosed the problem. Laptops that are constantly plugged in are often constantly on, producing lots of lithium-ion battery-killing heat. Even if they're not constantly on, they're probably used a lot more than the laptops that aren't always plugged in (more time exposed to heat == shorter overall battery lifetime).

    In other words, heat is the issue, not that that they're constantly plugged in.
     
  16. bufffilm macrumors 68040

    bufffilm

    Joined:
    May 3, 2011
    #16
    that would depend on the laptop. i have one that's always plugged in and it's not hot at all.

    about 2+ years ago, lenovo debutted software on their corporate thinkpad line which allows users to control custom control charging levels - you are able to set the low threshold on when battery the charging starts and also the high threshold on when charging ends which automated a lot of the battery management tricks which used to be performed manually. IIRC, they were the first to do this and to this day a lot of manfacturers still haven't adopted this technology.

     

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