iPhone turns off with battery life at 90%

Discussion in 'iPhone Tips, Help and Troubleshooting' started by Redwing91, Mar 24, 2013.

  1. Redwing91, Mar 24, 2013
    Last edited: Mar 24, 2013

    Redwing91 macrumors newbie

    Mar 24, 2013
    For everyone reporting issues with their iPhone shutting down prematurely, with the battery Charge showing 30, 40, 50% etc. I did a lot of work in the Air Force on devices that used Batteries for their main power source.

    My Wife's iPhone started shutting down and she would complain to me that this started to happen more and more as time went on. Well after turning on the Battery Usage (batter percentage "On") I started monitoring when she would see the phone shut down. 4 weeks ago it was at 50% and she would hook up the cable to charge it. Then it would come back on and she would let it charge back to 100%. What she and others are failing to realize is that you are now creating what is called Battery Memory Lock.

    What has happened is the Battery is now setting a new power threshold. Meaning when the battery is showing 72% the Memory on the battery is telling the phone I am at 0% and the iPhone shuts down.

    I am still working to clear the battery memory lock on her phone and I have to do this one step at a time.

    The batteries current memory lock was at 85 percent, using my laptop I plugged in her iPhone cable into my USB port and am using the power cord that runs my laptop and charges its battery to charge her iPhone. But what I am not doing is charging the battery back to 100%

    First step - If you have Anti-Lock set to lock if you can for now set it to never you can than leave the phone main screen on to force the battery to drain. Note: If it is a corporate phone and you can't set it to never then set it to the max time for auto-lock, on my phone it is 5 minutes.

    Second step - as soon as the phone shuts down and you see the Plug - Charge symbol plug your cable into your laptop or desktop only until you see the iPhone initiate the powering up stage. As soon as you see the iPhone apple come on and you let the iPhone turn on (see the icon screen) immediately unplug the cable from your iPhone. Don't let the phone start to charge the battery. This should clear the current Memory lock on the iPhone Batter and I am currently waiting to see when the iPhone will attempt to shut off again (hitting another battery memory lock)

    So far her phone has been on for 2 hours since I did this and her battery life is now at 60% which is now 25% below where it was initially shutting down.

    This may not fix everyone's battery issue as batteries do go bad, but in most cases your iPhone has gotten a memory Lock because instead of letting the battery drain down to 0% people will charge their phones each time they go to bed or are done using the phone for the day.

    Periodically allowing the iPhone to fully drain the battery to 0% will keep your iPhone battery or any phone battery from getting this Memory Lock.

    I hope this helps as it has helped me over the years in recognizing Battery Memory Lock and how to drain the battery past the Memory mark on the battery.
  2. farmgrange macrumors newbie

    Oct 3, 2013
    Iphone 3gs turning off when battery % is not empty

    Good Afternoon

    I am so thankful for the long explanation to the gentleman who wrote step by step details of draining batteries to extend thier life.

    I have a problem with my iPhone 3gs, just for the past couple of weeks.

    Never had a problem before, and always wait for any battery operated device to completely drain before charging.

    Now, without any other problem arising, whilst the battery metre is reading more than 40%, turns itself off without any warning.

    I did manage to keep its charge for nearly half a day, but as soon I press the home button it turns off.....

    After numerous switching ons, the battery must be drained by this action, as then I do see the charge notification, or complete battery drainage and turns off before a screen appears.

    I have completed the action of (via USB, charging until it switches on normally then unplugging the phone, it did drain to less the first few times, from over 40% to now 15%......

    Now, I have the apple sign but on start up turns itself off and will not get passed the start up apple screen, I have followed these steps many times until I see the charge sign again,,,,,,,,,,

    On one of these turns of being on the singed in page, I tried to use the message program directly it turned itself off again..........

    Please advise as I am very frustrated and becoming to think that a throw at the wall is imminent........

    I wait Patiently for your advise....

    Thank You
  3. verwon macrumors 68030


    Jul 26, 2011
    The 3GS is old, regardless of how well you take care of it, degradation over time is normal.

    And you can actually damage these types of batteries if you always drain it empty, before charging it, so that wasn't the right thing to do.

    It's most likely just time for a new phone.
  4. AxoNeuron macrumors 65816


    Apr 22, 2012
    The Left Coast
    The problem is not a memory. The iPhone (and most other smartphones) uses a lithium ion polymer battery, and these batteries do NOT display memory effects. What is more likely to be happening here is the charge indicator (Which shows you how much % battery life you have left) has gotten uncalibrated.

    I would suggest charging the iPhone up to 100%, and leaving it on the charger for several hours (around 3 hours). Then, take it off the charger and run it without charging it again until it shuts off. Then leave it UNPLUGGED for several hours while it is in this no-charge state. Then charge it back up again to 100%. and see if this fixes the problem. During this process, do NOT interrupt the discharge or the charging of the battery whatsoever.

    If it doesn't fix it, back up all your contacts to iCloud and all your pictures to your computer and do a FULL restore using iTunes. Do not restore it from any form of a backup, just log back in to your iCloud account on the device to retrieve the contacts.

    The chemistry of a modern smartphone battery is extraordinarily complicated, in ways you wouldn't even believe. But as complex and sophisticated as battery technology has come, there still isn't a method to directly measure how much power a battery has left. So smartphones use little software tricks and timers to try and estimate how much power is left in the battery. But sometimes these estimations become uncalibrated, so the method I have described above about charge/discharge/charge is a little technique to recalibrate it.

    If neither of my suggested methods fixes the problem then you are probably due for a battery replacement, in which case you should either call Applecare or take it to an Apple Store.

    Best of luck!

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