IOS 4.2.1 battery drain

Is there any difference if one charges the iPhone on the wall socket or USB on computer?
I read somewhere in the forum that the battery drains faster if the phone is charged via USB.

Lawrence, I've gone through all of your steps, and the only resolution has been when push email is disabled. Even after shutting off each of my 3 push mail accounts (I have MobileMe IMAP, Gmail IMAP, and Exchange) and doing the reset, problem was still there - too much usage: overnight ~8 hours since last full charge, would show ~3 hours usage, ~5 hours standby. I did a full reset and restored as new, did not load any apps back on and only added my email accounts... Same high usage levels unless I turned push email completely off (I compared 1 hour with it on - same 40% usage without touching the phone, and ~12 hours with push off - only a few minutes of usage). I reinstalled all of my apps between my push off and push on comparison...

I understand that the battery life I am getting (about 8-9 hours usage if I extrapolate out the battery percentage used vs. usage time logged) is phenomenal! But prior to the iOS 4.2 update, push email did not eat up this much usage time!!! Also - the excessive usage started immediately after the update, when I only had the Exchange account "pushing" on my phone. My other accounts I had were POP3 accounts that only checked manually when I opened the mail app (which I ALWAYS close all of my multitasking apps before I set my phone down!!). I just set up a MobileMe account and added Gmail to the phone yesterday...

All of these measurements / monitoring has been done while the phone is on WiFi..

My next experiment is to fully charge the battery today, and disable the Exchange account and just leave the IMAP ones running with push on. This will tell me if this is an Exchange activesync issue or push email in general. Regardless of the outcome, I have to have push on for my Exchange account as that is my work account, and I need to know when an email comes in instantly...

I will post my findings in a couple of hours, I just wanted to point out my issue found so far to see if maybe those of us having problems still, have something in common - I.E. Exchange Server 2010... Maybe an update is needed for Exchange or for iOS 4.2 to correct the method of activesync connections.

Victor Mihajlov wrote:
Is there any difference if one charges the iPhone on the wall socket or USB on computer?
I read somewhere in the forum that the battery drains faster if the phone is charged via USB.

Not drains faster, but the wall charger puts out 1 amp vs 1/2 amp for older computer USB ports, so the phone charges faster on a wall charger. Some newer computers can also supply 1 amp, so for those it doesn't matter.

I'm waiting to hear your results. I'm on Exchange 2007, but only recently upgraded from 2003.

When you turned off the Exchange account did you open the email app before rebooting? This seems to be an important step.

I've also seen a few reports that said turning off and rebooting isn't always enough; sometimes it is necessary to completely delete the Exchange account, reboot, and add it back.

I did open the app before rebooting. I've currently got it plugged into the wall, and have completely deleted the Exchange account, re-enabled push email, and done a hard reboot. Once I hit 100% (currently at 83%) I'll let it trickle charge for another 30 minutes, then pull it off and leave it sit for an hour without using it. Yesterday, 1hr44m of sitting untouched netted me 39m usage and 1hr5m standby - roughly 38% usage. I only received 3 or 4 emails during that period (all small 2-5k emails).

I'll let you know what I find!

Lawrence hi

Thanks for the advises.
The iPhone now works like crazy, yesterday it was about 10 hours of usage time, today it's the same...almost 24 hours since the last full charge and it's still about 80% of battery live. The phone has never work as good as it is now. I have wifi on, I have few apps and I keep mail app constantly closed from working in the background (off from the slider). I begin to wonder if there is something wrong with the phone..:))... Do you think it's normal? Previously the usage time was maximum 6 hours, now it's almost 10.

I do not think there is anything wrong. If you get a lot of email then mail will be the biggest battery drain except for games. If you keep email closed or set to Manual it will use less power. If you are connected to a WiFi network when you fetch mail your battery life will be better. WiFi uses less power than 3G. However, if mail fetches automatically it will use 3G because WiFi is off when the phone is asleep.

Ok here's my findings:

With Exchange account deleted, and MobileMe and Gmail active with push enabled:

After being off of charger for exactly 1 hour, during which I received 2 emails (one from each service), battery is at 100%, and usage shows 1m, with 1hr0m standby.

I setup the Exchange (2010) email again and left push enabled. Opened and closed email, calendar, & contacts until everything synced back up (to make sure it wasn't affecting my experiment by re-downloading everything). Did a hard reboot then put back on charger.

Let sit on charger for ~20m to trickle charge it back to full.

After about another hour off the charger, during which I received only 1 email (MobileMe), battery is at 100%, and usage shows 10m, with 1hr2m standby.

So definitely an increase (from 1 -10 minutes = 1000% more) in activity with the Exchange service enabled.

So now, can anyone else confirm if they are syncing to an Exchange 2010 server and having increased battery drain?

I'm going to leave it running with Exchange on until ~9pm and record the results, then delete the account, recharge, and let it run overnight to get longer lengths on each setup. Leave it to Microsoft to mess with my beautiful iPhone... 🙂

You should let your iPhone completely die and then plug it to the charger; but without using it, let it charge till it hit 99% or 100%. 🙂

Hi everyone. Brand new to the forums and I've already found a lot of useful information. When I first received my iPhone 4 about a week ago I went ahead and upgraded to 4.2.1. I started to notice battery drain but was unsure it was normal. I was a 1rst Gen and iPhone 3G user and kept thinking this battery isn't at all what I thought.

I don't use push email or notifications that much (mainly for FB or Twitter). After reading through this thread I decided that a bit of jailbroken code must have come through on my back up. I did a full restore and set up as a new iPhone. This seems to have helped. So now I was wanting a second opinion of my battery life and if this is about normal for my usage.

Right now my stand by time is 18 hours almost and my usage time is about 4.5 hours. I'm at nearly 40% battery. I live in an edge area and only use 3G when in town and when at work I use WiFi constantly. Those 4.5 hours include lots of photos (around 140...what can I say I love the camera and the editing apps I use), lots of uploads to Flickr and FB in a 3 bar edge area. Lots of editing photos. Lots of minigore, plants vs zombies, angry birds and risk. And about 1 hour of using music in my car plus a 20 minute phone call.

So is this about Standard? It feels a lot better. Granted it's lost 9% in the last half hour but I've also been on the web and checking out Flickr. I only lost 2% while asleep for 9-10 hours. So is my device good?

EDIT: I'm still waiting for it to die so I can recalibrate the battery which I haven't done since the restore.

Message was edited by: Moose967

Corrected a typo.

Message was edited by: Moose967

Moose967 wrote:

Right now my stand by time is 18 hours almost and my usage time is about 4.5 hours. I'm at nearly 40% battery. I live in an edge area and only use 3G when in town and when at work I use WiFi constantly. Those 4.5 hours include lots of photos (around 140...what can I say I love the camera and the editing apps I use), lots of uploads to Flickr and FB in a 3 bar edge area. Lots of editing photos. Lots of minigore, plants vs zombies, angry birds and risk. And about 1 hour of using music in my car plus a 20 minute phone call.

So is this about Standard? It feels a lot better. Granted it's lost 9% in the last half hour but I've also been on the web and checking out Flickr. I only lost 2% while asleep for 9-10 hours. So is my device good?

EDIT: I'm still waiting for it to die so I can recalibrate the battery which I haven't done since the restore.

Yes it seems like your battery is doing a good job as expected. So yes your device is good and superb.

Yep, right after the upgrade, I'm lucky if I get 8 hours out of it, and that is with it just sitting on the desk with nothing running and me not using it; compared to pre-upgrade where I got 12-15 hours with fairly moderate to heavy use.

So I called Apple Support (who was very speedy to respond I might add 🙂 and they recommended that I re-image it (backup Apps/data, restore OS, then restore Apps/data). I did this and it actually did not help, same battery draining problem.

So I did it a second time, and this time rather than restore all my Apps, I just restored a few selected ones that I have always used and never had problems with and this time it worked fine.

Now I should mention that I am a bit of a "free-App" junkie, I use one of the free-App search engines and do daily downloads to try (and often discard) some of the various apps that become available for free.

I can only speculate that all the installing/deinstalling must make swiss-cheese out of the file system, and possibly leave all kinds of rogue code scattered around the memory and file system, maybe processes that do not terminate and remain running/active in the background despite not being seen in task bar.

In any case, I'm back in business after the re-image which included a backup, restore of the iOS and "very selective" restore of just a few apps.

good luck

I found a solution which worked for me everytime I got the symptom since my last post yesterday (twice happened and twice solved). Just connect to WiFi or Cellular Data Network and wait for a few minutes and the symptom of bumpy scrolling screen will gone. (I am normally not connect to Cellular network or WiFi all the time.)

So I assume that the problem comes from some system process trying to connect/update something to its server and it should be system process because no other app can run in background.

Just want to share and hope it is helpful. I will try it when the symptom happen agan.

(I assume that the battery drain problem is from some process that consume too much CPU time and therefore battery.)

FYI: I have NEVER used Push Email, Game Center, any game network. I am a rarely used online service. Just phone, some chat and some productivity app. And the symptom has just happened after upgrading to 4.2.1.

Message was edited by: ZyberSup

Just find a way to get the symptom off in a few minutes without rebooting. Read it above.