I have an iPhone 4S and I just ran into a really weird issue the third time now: the battery percentage would suddenly drop 30-40-50%. One minute, it's, say, 69%, the next minute it's 25%. If I put it on a charger, it jumps back to 69% after a few minutes and charges it until 100% and then it works for a while.

It happened again today, I noticed that the camera apps were getting killed even though the battery was at 54%, and then after a minute, the battery would drop to 1% saying low battery. Then it died on me.

I also do not know how to calibrate.

I'm running iOS 8, non-jailbreaked.

  • I'm afraid that doing the hard reboot at the end is necessary for the calibration. Try it, and tell us if that solved the issue.
    – Thecafremo
    Commented Mar 12, 2013 at 8:48
  • Try restoring it and check the differences.
    – Rob
    Commented Mar 12, 2013 at 9:17
  • I'd wager this is a hardware issue. Software problems don't tend to manifest in such ways. It's likely a faulty battery.
    – user10355
    Commented Mar 12, 2013 at 9:23
  • I'm curious if the phone will actually die when it reaches 1% or less. So, if you just let the phone go (not charge it), when it jumps to ~25%, does it discharge from 25% percent like you would expect, and then power off? Commented Mar 12, 2013 at 16:29
  • My phone is doing the exact same thing. It isn't all the time, but occasionally. One day I went from 57% directly to 18%. Today I went from 37% to 20%. As soon as I put it on the charger it goes back to the percentage it was at before the drop.
    – user47031
    Commented Apr 8, 2013 at 21:35

1 Answer 1


I ended up replacing the battery myself. Have no issues with the new battery.

  • 1
    This sudden drop in capacity is a typical indication that the lithium polymer battery has exceeded it's normal useful life. It could also be a premature failure of the battery, but either way the solution is to get it serviced or replaced in almost all cases.
    – bmike
    Commented Nov 18, 2013 at 22:02

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