iPhone 5 battery algorithm 'bug' - real or myth?


macrumors regular
Original poster
Nov 2, 2013
Staffordshire, UK
I was talking to someone at work who has an iPhone 5, I've just got a secondhand one myself too. He was saying his 5 turns off at 20-30% since updating to iOS 7 (so far mine doesn't, ran it down to 19% with no issues). He said on forums, not sure which ones though that there is a bug of sorts with the battery algorithm that affects the 5 which makes it think the battery's prematurely flat at these levels and shuts the phone off. Apparently it's because it's optimised for the iPad and it's larger capacity battery. I've searched the forums here for this and found no mention of this, mainly hardware issues or debates on if it is software or not.

Is there any truth in this, or is it a myth? If it is software, is it something that will be fixed in the upcoming iOS 7.1 update?

Retired Cat

macrumors 65816
Jun 12, 2013
I haven't had any battery meter problems on my iPhone 5 with iOS 7. I believe the battery meter can become improperly calibrated, but this can be fixed by running the battery down and chagrin it up again.


macrumors 68030
Sep 15, 2012
My iPhone 5 was acting crazy right after I upgraded to ios7. It would shut down even at 50% charge and then would refuse to switch back on; even after plugging it in. However, a hard reboot seems to have fixed it (touch wood)..


macrumors 6502a
Aug 26, 2012
There were some threads on the apple support forums about this. I had the exact same issue, and it seemed to coincide perfectly with upgrading to ios7. Battery life seemed to halve over night, it would drop 1% in 1-2 minutes of usage, shut down at about 40% - so about an hour of usage. Doing nothing and turning it back on 10 minutes later, the battery may have increased to 60% or dropped to below 10%. If it had increased, I could sometimes get hours more usage out of it - so the charge was in there. Doing things like using the camera under 50% could cause the phone to shut down almost instantly.

I did a full reset, and it hepled for a few days, and then it started again.

I visited apple after a while, and they tested my battery and said it was in bad condition. I believe many of the recharge cycles they saw were since the problems started, as I had to charge it about 3 - 4 times per day sometimes.

I paid to get a new battery, and it worked fine ever since. I mentioned it only started after ios7, and that there were support threads of people with the same issue, and asked if they could change it for free - but they refused.

There were many, many pages on the apple support forum of people saying the same thing, and saying it started only after ios7 - so I think it had something to do with the software. Some people suggested that ios7 actually damaged the phone - i dont think this is sensible. But I do think the way it measured battery voltage, and managed the shutdown was different so that a tired battery acted crazy like this - meaning many more recharge cycles just to keep the phone awake, and so further wearing out the battery.

I have several iphone 5s, and this only affected one.
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