IOS 4.2.1 battery drain

my personal experience with the IP4 battery in general, is there are days that the battery drains more then others. it doesn't seen to matter the version of OS.

it seems like once ever 2 weeks, or maybe a bit more frequent then that the battery will drain twice as fast as normal use.

on a normal day the battery will still be at 80% by 9:00pm. but once every 2 weeks or so it will drain to 40% with the same use.

i close all the apps running in the background and do a reset by holding down home screen and sleep wake button until apple symbol appears. i will also re-sync the phone with itune.

after that everything is back to normal. i don't know why this happens, but no big deal.

battery is crushed after 4.2.1 update... draining 30% overnight

iPhone 3GS charged to 100% at 8am this morning - by 9.30am it had dropped to 33% !!!

Usage in that 1.5 hrs
Wi-fi on (not connected for most of the time)
BT on (didn't connect with my Ford Sync at all)
Played Angry Birds for 10mins.
Played Music for 30 mins total (via headphone jack)

Going to update the iPad and iPod shortly and see if the battery drain is equally spectacular.

Mindblowerz wrote:
Anyone noticed any battery drain so far on IOS 4.2.1?

some people will see heavy battery drain, but this is an artifact of the update process, not the specific version you have updated to. See these threads:


New iOS 4.1 is a battery KiLLER!
iOS 4.1 drains battery
Battery Meter/Life Problems with 4.0.2
4.0.2 guzzling my battery. Your's too?
4.0.1 battery life
Battery runs out very quicky in iOS 4.0.1
Battery nearly nonexistant after 4.0 upgrade
Dead battery after few hours on standby using 4.0 software
3.1.3 battery problem
OS 3.1.3 battery issues
3.1.3 upgrade - shortened battery life?
Battery life cut after 3.1.3 update on iPhone 3G
3.1.3 Firmware is a battery killer - how do I back out this upgrade?
Poor battery life with iPhone 3G running 3.1.2
3.1.2 EXTREME battery drain - what gives?
3.1 Battery nightmare
iPhone 3GS with fw 3.1 – battery life gets even worse
Battery Issues with 3.0.1
BATTERY drain with 3.0
upgrade to 3.0 drains my battery
Battery Drain after Update 2.2.1
Battery Life Radically Decreased after 2.2.1 Firmware Update


You need to find out WHY your battery is draining faster; there is either corrupt metadata in one or more of your apps or bad data in the backup that was restored as part of the update. There are many threads explaining how to troubleshoot this problem; don't just stick to 4.2.1 threads, as the problem is the same for any version.

Last night I was sitting at 51. With the app that runs overnight it dropped to 20% this morning. I have not charged the iPhone.

I have also been following this comment board

http://www.tipb.com/2010/06/30/troubleshoot-ios-4-battery-life-problems/

And a lot of people are saying that push notifications are the cause.

Weird thing is that after oct. 28 my battery would not last as long. Same with other people that have been posting on that forum.

you say: on a normal day the battery will still be at 80% by 9:00pm

With this scenario what would be normal use for you….
I agree with you just last week the battery dropped in a matter of hours, after the charge it seems as though the batter like was much better, but recently is has gone back to about two full days of usage before a charge is needed, below 20%...

Yes, Big drain after the update. Now I must charge twice s day.

I never had to pay attention to the battery until the last night's install... I was like "I am at 15%, really?" I never had my battery levels this low.. reason- it drains so quickly

Turning my iPhone on/off did the trick for me after I noticed the battery immediately went to 99% after unplugging from the charger.

After the on/off cycle, the battery meter went back to 100% and I have only lost 6% in the past 6 hours with one Skype call included during that time and lots of playing with the new iOS. 🙂

So far, bouncing the iPhone (home button + on/off button) seems to be on the way to correcting the matter. I did this a couple hours ago, and still sitting at 100%. It also corrected a problem that began after the upgrade whereby cross-swiping in any application that supports the swipe/delete (i.e. Messages, Mail, etc.) the Delete button would appear and disappear so fast that you could not actually press it. This is also now fixed. I hope it holds up.

It happened on my iPhone, I just open wifi and didn't do anything at night, and when I woke up there's no battery at all! It seems the wifi still working even there's no apps running!

I am having the same problem. I have a 3G and have been dealing with battery issues since the first 4.0 update. However, I upgraded to 4.2 yesterday and the battery began to drain fast. Today, after being charged, my battery drained down to about 20% by 1pm...and yes, I've tried all the "Fixes" and made sure that nothing else is running in the background.

Lukerb wrote:
I am having the same problem. I have a 3G and have been dealing with battery issues since the first 4.0 update. However, I upgraded to 4.2 yesterday and the battery began to drain fast. Today, after being charged, my battery drained down to about 20% by 1pm...and yes, I've tried all the "Fixes" and made sure that nothing else is running in the background.

"All the fixes" is a tall order. Have you tried:

Deleting your email accounts, rebooting and adding them back?
Disabling multiplayer games in Settings/Restrictions?
Turning off Notifications?
Erasing All Content and Settings, then Restoring as a new phone?

After upgrade, battery fully drained after 3 hours. Was lasting 2 to 3 days before.
Full reset didn't change anything.

If you have any Push email accounts, go into Settings and turn them off (the accounts, not push). Then open the mail app, verify they are gone, and go back to the home screen. Now do a reset (hold HOME and SLEEP until the Apple logo appears). Turn the email accounts back on. This usually fixes sudden battery drain problems. If it doesn't post back and there are other things to try.