After weeks of trying to figure out the cause for battery drain in IOS 6 / 6.0.1, I found something that worked for my phone. The main culprit seems to be iCloud & email (particularly Exchange account) syncing.
Make sure to sign in to iCloud (Settings >> iCloud). The only option that needs to be on is Documents & Data (Use Cellular Data can be set to off), others can be checked if needed, but leave off Find My iPhone. After that make sure to backup your iPhone to iCloud via WiFi. This ensures whatever is on your phone matches whats on iCloud. If there is an application on iCloud thats not on your iPhone, delete it.
Prior to doing this my iPhone kept the 'ubd' process running constantly. Deleting iCloud on your iPhone doesn't solve it either, it will only cause the 'ubd' process to restart in an infinite loop (~ every 10 seconds). Doing whats outlined above will cause 'ubd' to run for a short time then terminate.
If any Exchange email accounts are added Push needs to be set to On (Settings >> Mail, Contacts, Calendars >> Fetch New Data). The Fetch option below that can be set to whatever, I have mine set to Manual.
Prior to doing this my iPhone kept the 'dataaccessd' process running constantly. Setting all Exchange email accounts to Push immediately fixed this issue. Now this process is only active when manually checking email or new email is pushed to the phone.
These 2 changes dramatically improved battery life on my iPhone. There still seems to be a bug with Location Services, specifically Traffic and how its used in Maps. It causes the 'geod' process (related to GPS) to run erratically. Still trying to figure this one out, will post if any luck.
I really hope Apple is monitoring this stuff as we are doing all their troubleshooting for them. I am finding it really hard not to use expletives here so that my post doesn't get blocked. All IT companies have problems - but this radio silence from apple on a widespread issue (there's about 10 thread running. Have counted with several hundred thousand views) is unbelievable. I thought they were supposed to be a 'cool' user focused company. This is like Microsoft in the bad old days.
Anyway, continuing to trouble shoot the battery drain in my 2 4S units since IOS6. I have done multiple 'install as new' resets without any change.
Following other suggestions this morning I turned off mobile data- so device is restricted to wifi and 3G phone and SMS. No heating up and minimal battery drain (99% after three hours on standby! )
Of source this isn't what I bought the **** thing for but it DOES tend to confirm the problem is in the mobile data area. ALSO if mobile data is ON the battery drains even when the unit is logged onto WIFI and on standby. Also heats up at the same time.
What does this imply? I'd say that the cellular radio is being driven FULL THROTTLE even when the device SHOULD be using wifi and/or on standby. Implies a pretty significant BUG in the control of the cellular radio.
Apple are you listening?
I don't know how to get this information through to anyone who cares.
I'm not an expert radio engineer but have spent the last 25 years of my life diagnosing issues with remote networks, switch gear etc and circumstantially I'd be looking at conflicts with the cellular radio.
Also - as we have no idea whats inside the box if there have been different chipsets used in the different fabrication plants that would explain why some users get this problem and some don't?
Thoughts? Anyone out there?
If you turn cellular data off then you're also turning off 3G. Say goodbye to MMS piccies too. No cellular data = 2G.
My i4 has performed abysmally since losing iOS 5.1 and it isn't just cellular data leak and battery drain. Safari is often slow to load webpages and experiences freezing when loading, I have to refresh. In-call volume on the lowest setting is much higher. Assistive touch and screen lock glitches.
Yep losing 3G is not a solution - I was mainly trying to point out that certainly in my case thats where the problem is. Using the phone in exactly the same way but over wifi battery life is fantastic. Just got 7 hours and only down to 82%. That includes having all my exchange mail accounts enabled etc. haven't disabled anything else. Locations services on, etc etc. but have been within wifi all that time....no overheat, no battery drain, everything working fine.
Enable mobile data and I can watch the battery drain,......system overheats.....max is 6 hours to drain the battery even though I am still within the same wifi location......so it should be using wifi........
So my assumption is that as soon as mobile data is enabled system wireless goes on and stays on and full power? Shouldn't be doing that if its in wifi as that should take precedence......but it doesn't.
And for those that says is the exchange push settings.......settings are exactly the same under wifi and no battery drain (but of course a smartphone without 3G is not smart)
I fully agree to scubaal and his sound analysis. it's exactly what I think too.
But at least I had the success that after restoring as new phone it would get much better, but after a few weeks it not as as good anymore again.
So it least has to do something with the old profiles, too.
And now with cellular data off (as I'm mostly in wifi area anyway) it's way better:
65% battery after 36hrs standby and 3hrs normal use.
The really sad thing is people switching to Android over this. but I can fully understand..
Here's another update - btw, while writing this post I lost 3% battery.
1. I installed iOS 6.1 beta 2 for developers. Hoping this will help. It didn't.
2. Even though I turned push notifications completely - I still get e-mails in push.
3. Yesterday I had 81% battery (after about 10 minutes of use). I restarted the phone and my battery went up to 84%! What's going on with you apple?!
Thank you Msf01,I'll try that too. One question: got 3 email accounts, one is exchange, another one is Gmail and the third one is Yahoo. I've set Push to ON and fetch to manually. Under Advanced everything is set to Manual, or does the Exchange account still have to be set to Push?
Thank you in advance for your reply.
@scubaal -- to monitor what processes are running download a system activity monitor from the App Store. The app I use is Battery Monitor (BMSSM). It will show you what processes are loaded in the background and current state (active / idle). As you adjust settings you will see whats going on with these background processes.
@Valerio70 -- Under Advanced all Exchange acccounts should be set to Push. As for Gmail & Yahoo, you can set them to Push if given as an option. However, I'm not sure if Push is supported by either. If not supported (emails not being received) set those to Manual or Fetch.
So here's whats working for me. We have four iPhone 4S in our house. The two updated to 6.01 show the battery drain problem, the two left on 5 have no issues.
When mobile data is ON and email PUSH is ON the battery life drops to 6 hours max and phone heats up. This is with NO use of the phone, ie its just sitting on the side with the screen blanked out after 5 mins. Max battery life is 6 hours even making and receiving no calls, no browsing etc etc.
This is the case even though the device is within and connected to an active wifi network so should be using that.
Interestingly checking the usage shows USAGE 6 hours AND standby 6 hours ie the phone THINKS is has been fully used thoughoutthe period it's been sitting on the side.
This goes to support my contention that the cellular radio is on full power all the time.
Turn off mobile data. Everything keeps working but now battery does not drain. Usage data shows Usage 6 mins, standby 14 hours! So when the cellular data is off and unit is working on wifi. Even with PUSH on it correctly thinks its on standby when it's just sitting there.
So this morning I turned cellular data back ON and turned the exchange mail account onto 15 minutes scheduled updates. Battery life is the best it has ever been. Now 91% after 14 hours! Usage data shows Usage 42 minutes, Standby 14 hours. So with PUSH off, mail pickup scheduled for 15 mins problem has gone away, no heating up no battery drain. Note, I left everything else alone, so I still have location services.
My assessment - at least one of the bugs we are looking at here (there may be many) is that when there is a PUSHmail account and mobile data is on the cellular radio gets driven at full power all the time which causes the battery to overheat.
Apple I've done the diagnosis for you. Fix it.
Should have pointed out that I did that with both 4S phones that
had the problem (turn off push mail and set to 15 min schedule) and got the same result. Pretty conclusive. Battery life now the best we have ever seen (even under IOS 5)
So I have a work around, hope this helps others until apple pull their figure out and produce a real fix.
After trying all that was suggested in these discussions, I've found that turning off automatic time/date updating has restored battery use fractionally. Keep in mind, I don't use notifications or location services or anything that would cause my iPhone 4S to lose charge. I always keep email set to update when I open mail, and am a very light user of my phone for any function. I am still not completely satisfied with my battery life after iOS 6 update.
'Hope this helps some folks.