I'm still of the opinion that the issue described by the OP (and by most of the other posts in this thread) is an iOS7 issue; not a battery issue. However, a few of the posts do sound like battery issues. My guess is that two different problems are being mixed together in this thread.
I also want to comment on Gjeratore's post of Dec 15th in this thread. On some of Gjeratore's points I hold a different opinion, so I'll offer some alternative views here. Caveat: All my comments are IMO only. I am not a battery engineer.
Apple iPhones use Lithium-ion polymer batteries. (See: http://www.apple.com/ca/batteries/)
First, I agree with Gjeratore that using and recharging 100% of the iPhone battery's capacity equals one full charge cycle. (Apple states this at the link provided above.) It doesn't matter if this is two instances of discharging to 50% and recharging to 100% or ten instances of discharging to 90% and recharging to 100%. Each of these two variations counts as only 1 discharge/charge cycle. All batteries can handle only a finite number of cycles before failing. To the best of my knowledge, Apple has not publically put a number on this for iPhone batteries.
Second, I disagree with Gjeratore about battery memory as it relates to Lithium-ion polymer batteries. Lithium-ion polymer batteries do NOT have any "memory effect". Nickel-cadmium batteries, on the other hand, do have a "memory effect". Ni-Cad batteries are also susceptible to failure from overcharging. Lithium-ion polymer batteries are NOT. The Lithium-ion polymer battery in an iPhone can be recharged at any level. IMO, they can also be connected to the charger continually without damage. My opinion is in direct contradiction to what Gjeratore has stated, so I'll leave it to the reader to decide who is correct.
Third, as stated at the Apple URL provided above, lithium-ion polymer batteries should not be stored unused for long periods (that is, the iPhone should not be left turned off for long periods --- weeks.) Lithium-ion polymer batteries need to go through at least one discharge/charge cycle every month. If it must be stored unused, the batteries should have at least a 50% charge before storing. This last tip comes from here: http://www.apple.com/ca/batteries/iphone.html
Just my 2¢
I've been keeping an eye on the discussion and need to reply to this.
Logy is 100% correct - physical (chemical) battery memory effect was eradicated with the NiCd (Nickel Cadmium) battery - a rechargeable technology that still has a place in photography where the particular discharge characteristics suit high speed flash, but that's about it : otherwise it's a cranky, crappy, dirty way to make a cell battery.
I also agree with Logy (and said earlier, although possibly on one of the posts Apple helpfully deleted) that I'm pretty sure there is more than one problem being rolled up here.
There's plenty of empirical evidence to suggest a software issue, which would see a short term 'fix' from battery replacement just as they do from what used to be called 'conditioning' back in NiCd days - but not for quite the same reason. In the case of NiCd, this busts the memory of the cellpack, in the the conjectured case here, it corrects a firmware counter issue. The important thing is that rechargeable technology has been chasing a holy grail of stable output voltage right up to empty - and Lithium Polymer like in the current iPhones pretty much achieves this goal. This is great as it means you don't need to make a battery bigger than it needs to be to account for a chunk that holds charge still, but discharges at too low a voltage to be useful in the application (think dimming flashlights etc) but also means that traditional battery meters which track cellpack voltage are not helpful. Apple are keeping very quiet about this, but we think their current firmwares are essentially counting units of charge going in and estimating likely use by some form of profile on the way out - the effect of which if you get these counters out of sync pretty much replicates the memory effect in software. If you have the software issue, then the conditioning deep discharges then full charge process is likely to get you running again for a few weeks.
There is a useful life on any rechargeable battery in terms of charge cycles, however. Apple quote about 1000 charges for the iPhone, and without very hard sums this should show that daily charging, which is what most people do, should give you around three years - at which point no iPhone 5 should yet have a problem but 4's and 4S's may. And this is where the second critical point is: if these '1000 cycle batteries' are not posting their forecast three year service life, are they fit for purpose? In the US it only really matters from a soft 'goodwill' point of view as Apple's one year warranty stands up unless you bought AppleCare. In the EU it's less clear cut though, and if there are a bunch of under specified or badly manufactured batteries out there, Apple could be liable to make good every handset sold going back two years - which is going to hurt the bottom line - although Apple and your Network will both try to tell you that the othe is the Vendor for the purposes of EU Law and you may need to be harder headed about your dealings than you should need to be.
The point is that as Apple are keeping quiet on this and the big Tech news outlets are ignoring the story still, we only have conjecture at this point and empirical evidence. It would be interesting if everyone here got their battery replaced and we reconvened in two months, but based on the number of people who experienced the issue first with nearly new hardware after a particular firmware update, I'd be surprised if wholesale battery replacement is the answer.
Small update on my issue.
After some more weirdness with my phone's battery I called Apple Support (Belgium).
Asked me to reinstall iPhone with clean install, no restoring old backups because there might be a bug
in the backup causing the battery issues.
Test the clean install for a few days, if the problem still persists I will receive a new battery.
I have been running iOS7 since the keynote and have not experienced this battery issue until very recently. I believe it has only been since after installing 7.0.4, but I have no way of proving that. Both of my examples happened while using Bluetooth: Last week I went from 30% battery to "dead", and a few days later I went from 50% to "dead". I had a charger close by in both instances, and they each popped back on with close to those two amounts upon restart.
I decided to make a Genius appointment the next day, and I was given the same recommendation as many of you despite him saying that my issue was a rare one: definite signs of battery wear, better off getting a battery replacement. Sadly I'm out of warranty and am not too keen on dropping the $70+ for a new one.
Hopefully there's more media coverage of this getting out there, I got to this forum because of an article I saw on applenapps.com.
Hoping for a fix in the next software update!!
I have a friend who started having problems after iOS7, while mine didn't start til 7.04, meaning within a day or two. This is a huge issue and I think the users would be very forgiving if Apple owned up and said they know it's a problem and it's going to get fixed on the next update, instead of sweeping it under the rug and deleting posts on this forum. I believe it is totally a software issue related somehow to the way the software keeps track of the battery status.
Right, small update. Did a clean install. Charged phone to full.
It lasted about 36 hours with light usage (almost no apps reinstalled) before it reached 8% battery life and then shut down. Restarting it using the charger for a few seconds gave me 6%. Shut down again, restarted to 7%.
Then dropped to 3% in 2 minutes.
Called back to Apple, getting a new iPhone 5 to replace this one. At no cost. My iPhone is 15 months old.
I'm sure software is involved given the timing but you have to consider whole systems especially when parts may have been substituted in different production runs for items of nominally same spec but with potentially different behaviours.
From a producer's point of view, if only historic batches are affected by new code that runs better on more current hardware, it's difficult to see why they would want to back out the change for everyone - upspeccing a number of more recent but historic devices (14 odd month old iPhone 5's) may be a better/cheaper solution for them. Dunno. I'm reaching here, but trying to put all the pieces together.
The deep calibration, as posted many times I'm many places is *not* a fix but may (depending on exact symptoms) make your phone a bit easier to live with for a few weeks.
For the record, after behaving reasonably for a few weeks following a PITA evening carrying out full drain, my iPhone 5 died at 80% yesterday, taking non flash pics out doors with temp around 8-10c. At this point I reached for Apple diagnostics, which diagnosed 'a power problem' (you don't say) and assistant can't wait to get my phone and charger into my local store. I'll let you know how this pans out.
Update on the EU warranty situation btw: since last time I had warranty issues (ie items broken just outside Apple's one year limited) and experienced 'pass-the-support-case' between A and network, they've updated the site, and it now recognises EU rights :)
I contacted both Vodafone and Apple about this issue with my iPhone 5
Vodafone: For a company making such vast profits and paying so little tax their customer service is shocking. Level 1 support gusy just bleated about 1 year warranties and insisted they are not a retailer. I requested escalation to be told no manager was available but that somebody would call me within 24 hours. 2 days later I got a call from a lady who kept telling me that the Sales of Good Act didn't apply to Vodafone as they are not a manufacturer. Yes, really. I requested escalation again to be told somebody would contact me within 7 days. I am still waiting.
Apple: A rather different experience. Escalated straight through to a very helpful guy in Cork. We discussed the issue and he asked me to do some diagnostics and then reinstall the IOS software. I did so and left the phone virgin with no apps for a day. I logged the problems with apparent battery drain and inconsistent reporting of battery levels after plugging in the charger which continued to occur (although oddly when using maps but not taking photos). The next day we had another converstaion after which he put me straight through to a customer service agent who discused the issues again and agreeen to make an exception to put my phone back into warranty so that I could get an exchange unit. She did make a big thing about the number of Apple products we have to justify doing this (we have 4 iPhone and Ipad a macbook and Apple TV registered with them.
Within 24 hours my new Iphone was with me and I have not yet had any problems with it.
So - Vodafone - you customer service is shockingy bad. Apple on the other hand behaved impeccably and I have only praise for the way they dealt with my case.
I took my iphone 5 into an Apple store and they ran a diagnostic test which showed that the battery was not performing correctly and needs servicing (I.e. Replacing). This would cost me £55 as the phone is 3 months out of warranty.
I'm not particularly happy with this but it seems I have to just suck it up.
I still don't understand why this hardware problem only manifested itself when I installed ios 7. Is it possible for software to screw up hardware?
A couple of days ago I did a complete reset of the phone via itunes to effect a clean installation of ios 7. I've read that this has helped some people. If it truly is a hardware issue though I don't have high expectations.