Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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.

share|improve this question
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 Mar 12 '13 at 8:48
Try restoring it and check the differences. – Rob Mar 12 '13 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 Mar 12 '13 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? – bassplayer7 Mar 12 '13 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 Apr 8 '13 at 21:35
up vote 1 down vote accepted

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

share|improve this answer
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 Nov 18 '13 at 22:02

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.