iPad mini What really is the point in draining battery to 0 percent once a month

Discussion in 'iPad' started by srkmish, May 28, 2013.

  1. srkmish macrumors regular


    Feb 10, 2013
    Hi friends,

    As far as I have researched on the Internet, today's lithium batteries pretty much take care of themselves and a research has been done which shows people who charge their mobiles more often ,their batteries last longer than those who frequently drain it.

    can you guys post ur experience of battery optimisation techniques and is it really necessary to drain it to 0 once a month as recommended by apple
  2. Menel macrumors 603


    Aug 4, 2011
    It's for calibrating the percentage meter.

    Repeated shallow discharge/charge cycles can cause miscalibration. e.g. reporting 50% when you really have 80%.

    Once ever month or 3. Don't do it intentionally more than that.
  3. darngooddesign macrumors G3

    Jul 4, 2007
    Atlanta, GA
    You can do it every other month, its not going to hurt your battery.
  4. Mrbobb macrumors 601

    Aug 27, 2012
    Mine rarely goes down to single digit so I don't need any precision, hence I forgo the suggested monthly calibration. It feels so great not to have to babysit these gadgets.
  5. tazz3 macrumors regular

    Apr 26, 2013
    apple has a page about this on theer web site
  6. zorinlynx macrumors 601


    May 31, 2007
    Florida, USA
    Lithium batteries last longer when not kept at a full state of charge all the time.

    Best practice with an iPad, if you have access to a charger every night, is to get it down to about 30-40%, then charge it. Charging it every night will cause the battery to spend more of its lifetime at a full state of charge, which causes faster gradual chemical breakdown.

    Note the recommended storage guidelines for Lithium batteries: 50-60% state of charge, cold location.
  7. SnowLeopard2008 macrumors 604


    Jul 4, 2008
    Silicon Valley
    Basically, just use it and don't worry about draining it fully or keeping it fully charged. Don't intentionally go out of your way to do either either.
  8. iamthekiller macrumors 6502a

    Feb 3, 2010
    There is no truth to this stupid belief. It's not necessary or beneficial with today's modern batteries.
  9. charlituna macrumors G3


    Jun 11, 2008
    Los Angeles, CA
    That's not really true. Lithium batteries have a set cycle count life and it's the same whether you zero out every time or not. The only difference is that the math is dealing in partial cycles not full ones.

    The draining it out is more for the software than the battery. Particularly with iOS devices since the same software is running batteries of very different sizes. The meter software can become corrupted just like any other software in the system so a full drain to shut off periodically helps to keep the meter correct so it doesn't report you have battery falsely when it is in fact drained.

    All of this though is secondary to the issues of never running the battery (ie keeping it on the charger all the time) or having it drain out and now charging it for ages (which means even the trickle charge drains out eventually). Those two things will kill your battery more than how often you charge it
  10. hchung macrumors 6502a

    Oct 2, 2008
    Properly designed lithium battery chargers don't actually keep trickle charging the battery unnecessarily. Many of them don't even turn on the current flow if the battery is between 95% to 100%, so the issue you mentioned at the end shouldn't happen. (Some will have tricks for refilling them at the end and it's all right, but leaving a lithium battery on the charger indefinitely should never be a problem on a proper charge)

    Partial cycles arn't uniform across charge levels.

    I recall if you charge from 0 to 10%, you apply more wear and tear to the battery than if you charge from 60%-70% even though they're both 10% of a cycle.

    Also, past 4.0 volts, it's best to charge at a slower rate to keep the heat down because then you'd also have more wear and tear than the middle. Do that and you'll keep the upper end wear and tear to a minimum.

    Ideally, it's best to keep your battery in the middle 1/3rd but that's not really feasible. Next best is to always keep it as full as possible. Worst is to drain often and then charge it back up entirely frequently.

    (I had to design a lithium polymer battery charger a while back for a side project. Got a bunch of research done, but turned out it was much more worth it to use off the shelf components than to actually implement our own so never finished it.)

    With that said, I only deliberately do a full drain calibration cycle on my device when I first get it. And always try to leave it on the charger if I can. Oh, and if I have a choice, always the slowest charger I can get if I have the time.
    This calibration thing? I'll do it again in 2 years if I still use the device. Certainly not every month.

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