Q: iOS 6 iPhone 4s battery drain

Sorry, just have to answer... If you put it in Airplane Mode, you have a iPod.  teehee

True.

This has me beat. I'm starting to cook up conspricay theories!

Seems to be the cloud......

I had the issue. Thought I solved it a week ago with a complete reset of the phone and restore from backup but noticed today my battery dropping again. I have been using System Status Lite (free) to see how loaded my CPU is. When things are working as expected, with very few apps running, I can see my CPU stays below 10% almost all the time... usually less than 5%. When the battery drain issue is happening the CPU is constantly spiking over 50% and rarely goes below 20%. If I put it in airplane mode it immedately drops down into the sub 5% range as expected.

I found the solution for me. Turned off iCloud sync for Contacts and Calendars. I left mail syncing and Find iPhone on. I am now into the sub 5% range and no sign of the peaking 50% plus that I was seeing a moment ago. If I turn on Contact sync I get an immediate return to the 25-50% plus range. Completely repeatable for me.

So my advice for anyone troubleshooting this issue is to use some sort of CPU usage tool (System Status Lite works for me and is free). Start up the app and watch your CPU usage. It even tells you 1 minute, 5 minute, 15 minute averages to see the trend). With nothing running and just watching the meter you should be seeing about 5% or less. If you are having battery drain issue you will be seeing 25-50% or more. Start disabling iCloud features and see what happens. As a quick test enable airplane mode and you should see the <5% usage number immediately.

This is a great way to see instant results rather than checking battery drain over X minutes.

Weird how we're all having different experiences. I turned off all iCloud syncing yesterday and it made no difference. I'll try measuring cpu load, like you say - I've noticed everything's a bit jerky so that might well give instant feedback.

BTW, stopping mail push might be having an effect - won't know until I've watched the wifi data a bit longer.

You may have nailed it there dadioh. I have just checked my iCloud settings and the thins that are on are Photo Stream, Documents & Data and Find My iPhone and to be honest it wouldn't bother me if I switched these off. I have stopped even using my ME.COM email.

The battery runs down and at the same time, the processor gets hot. Just goota search everything that may be causing all that processors usage. With iCloud pared down to minimum, no push email, not location services, simplyfied email accounts (I only use Exchange for Google Calendars and Contacts and for Google email I set up in Other Account.....), etc. etc. etc. the processor may not have much to do.

Is this for real?

I was just about to update my iphone 4s, and I read all these...

This could be catastrophic for my wallet!

Here in Greece the mobile providers offer a limitded amount of MB per month.

I can use only 100MB/month and then I pay 2€ for every 30MB I download!

@GrahameE: Your email push thing apparently did it for me. The past hour has only seen a fraction of a MB, compared to 5 or more per hour previously. The battery seems to be holding up but it's a bit early to tell because practically everything is turned off right now.

It's hard to know what to make of it, if the only common factor is reducing data flow by whichever means happens to work on a phone-by-phone basis. I'm not so sure the heat actually comes from the cpu. Running the cell or wi-fi radios for long periods creates high current drain and heats those chips as well as the battery itself. So cpu consumption might just be an indirect indicator that the system is very busy pushing stuff through one radio or the other.

Either way, iphones are not supposed to send cellular data at all while they have a wi-fi connection. That was definitely the primary source of battery drain for me, because 90% of the problem went away when I turned off cellular data. Sadly I didn't figure that out before going over my data limit.

So now, if I don't actually use my phone for anything at all, its battery will stay reasonably happy. Great!

EDIT: I take some of that back. Wi-fi use is down to a trickle but the battery's still dropping faster than it should, so maybe it is cpu cycles after all. I'll check that next. But it still shouldn't be sending 5MB/hr, nor using 3G while on wi-fi, so it's not just that the cpu is being hogged. Dammit! I'm supposed to be debugging my OWN software right now, not Apple's :-)

@mad_nassos: Yep, it's for real. It only cost me $15 but lots of people on the web are going through data at a crazy rate. It's not the phone itself - it happens on all models - so you can still upgrade, but just watch your data use and switch off cellular data completely if you get close to your limit! That stopped things getting worse for me.

I had my cellural data enabled during July and August, but I kept 3G off as I noticed battery drain.

During these 2 months, my phone didn't overeached 150MB/month!!

I had some notifications on, facebook app on and Mail app off

I'll check it again though!

Update:

In my tests, mail pushing uses quite a bit of data AND definitely uses 3G, even when on wi-fi. Watching YouTube works through wi-fi perfectly normally, but not mail push, so it's not the wi-fi connection itself (and anyway, my phone is three feet from the router).

I turned back on all my iCloud syncs and they aren't using any significant 3G bandwidth - so far it's only mail push.

I have a very weak 3G signal here, so the radio has to run at full power. I blame this rogue 3G data use for my battery problems, which are now greatly improved. However, I think there must originally have been more activity than just the 5MB/hr that mail push seems to burn. Maybe I still have something turned off that was originally on.

Why mail push needs 5MB/hr or why it insists on using 3G when I'm connected to wi-fi are a mystery only Apple can answer!

The battery life on my iPhone 4S after updating to iOS 6 is absolutely atrocious. Can't even get through an entire workday, even when it's on standby in my pocket. I've disable wi-fi, Bluetooth, iCloud sync, etc. Still... Nothing.

Apple you should be ashamed of yourself.

In my opinion, iOS 6 is complete crap. This coming from a longtime Apple fanatic.

that is the same for me.

i turned of my iCloud, and my battery went normal for about two days.

after that its one back to draining out a lot.

it's getting really annoying now.

might bring it to the store and writhe battery checked.

Just an update for everyone… An Apple rep contacted me and I sent him my battery log. Have not heard back from him and it's been days. The battery drain is still very significant since I've upgraded to iOS 6. The battery life I had pre-iOS 6 made me feel my phone was a worthwhile investment. Since the upgrade I feel that I've wasted my money and I no longer trust Apple. The fact that they will not publicly acknowledge the battery drain issue with iOS 6, but will apologize for the Maps app is a joke. The Maps app is not even that bad. I'm disgusted with Apple. I feel that the current CEO cannot handle the business. I just know that the company does not seem to embody the values and the vision that the previous CEO had. There Apple Care Support staff does not seem to care. It doesn't seem like the left hand knows what the right hand is doing. I understand that it is normal for companies to get so big, they become disjointed. However, we all expect more from Apple. Yes, the pressure is on and we expect them to step up to the plate and deliver an amazing performance. They are supposed to "wow" us with their innovation and performance. Instead, they are "wow"-ing us with their blatant disregard for consumer complaints and needs. They are not placing the customer at the center of everything that they're doing. They're losing consumer confidence fast. Although they may get sales from their new phones, consumers will come to the same conclusions about Apple we have voiced in this forum. It's a shame too.