IOS 4.2.1 battery drain

No, you don't have to turn everything OFF.

I have everything ON (Push, Notification, Location Service...) and didn't delete email account or empty email box.

The only thing I did is to turn OFF "Find My iPhone" (go to setting->email->MobileMe and turn it OFF).
And my battery is back to normal. My old iPod Touch 2g can now keep all 100% of battery for many days if I don't use it.

As soon as I turn "Find My iPhone" back ON, battery drain starts again.

Can someone just try it? see if it works? Please report your finding.

Try to put different phone card. Only thing that helped me.

But the last time I checked it out I got 11 hours over an almost 3 day period without charging.

i confirm this. my battery started draining very fast (1% per 5 minute) without doing anything, after cold reboot, with all connections OFF.
Then i removed MobileMe and the battery stopped draining as fast. Now i lose 1% every 2 hours without doing anything; however i don't know if this is normal.

Never had a mobile me account. Never activated.

But I'm glad it's has worked for others.

Still draining here.

Apple HELP!!!!!
Tell us your fixing this. All was fine before 4.2.1

Apple doesn't read these. This is a user to user forum.

To get through to Apple you need to use their feedback link.

After turning OFF "Find My iPhone" from MobileMe account (or you never turn it ON), if battery still drains without using it, install this configuration profile (from Apple) :

1. on your iPhone (or iPod Touch / iPad), open this link :
http://support.apple.com/kb/TS3398
2. then click "Download signed configuration profile"
3. click "Install"
4. Reboot your machine (Power+Home key)

This will stop the frequent background data transmission. I tried it and it seems to slow down battery drain.

Please try it and report your finding. You can always uninstall later if it doesn't work.

to n2david:

I am glad that you tried and confirmed that "Find My iPhone" in MobileMe account does cause severe battery drain.

I hope whoever read this please give it a try. The we know it's not the iOS4.2.1 upgrade, it IS the "Find My iPhone" that is eating all the battery power.

I still like to use "Find My iPhone" when Apple fixes this problem.

So I just recently got a brand new iPhone4 as an upgrade from my 3GS. Unfortunately the battery life is so atrocious that I have quite carrying it. From the looks of this thread it seems I am not alone so this is likely just piling on but figured I'd share all the same.

First suggestion was that it was because I "restored" my previous backup... so I completely erased the device and re-installed. No Luck.

It was then suggested that it was because of backgrounded applications so I closed everything down and let it sit. Not the cause either.

Next it was thought that as I'd moved into an area with No Service that the radio would periodically fire up draining the battery to try and connect. So I decided to turn on Airplane Mode and let it sit.. Here are the results.

With Airplane mode ON and the device at 100% at 2141hrs it had dropped to 28% by 0715hrs. The only thing "open" (the device was left on the home screen) was Camera, Settings, Calendar.

So in less than 10hours there was an 72% drain on the device with NO connections what so ever and doing NOTHING.

With Airplane mode ON and you still have 72% drain !

Well, maybe you can also try the following (suggested by Apple), see if it makes a difference.
And most importantly, turn OFF "Find My iPhone" in MobileMe account.

Turn off Bluetooth: If you rarely use a Bluetooth headset or car kit, you can turn off Bluetooth to save power. Go to Settings > General > Bluetooth and set Bluetooth to Off.

Adjust brightness: Dimming the screen is another way to extend battery life. Go to Settings > Brightness and drag the slider to the left to lower the default screen brightness. In addition, turning on Auto-Brightness allows the screen to adjust its brightness based on current lighting conditions. Go to Settings > Brightness and set Auto-Brightness to On.

Turn off EQ: Applying an equalizer setting to song playback on your iPhone can decrease battery life. To turn EQ off, go to Settings > iPod > EQ and tap Off. Note that if you’ve added EQ to songs directly in iTunes, you’ll need to set EQ on iPhone to Flat in order to have the same effect as Off because iPhone keeps your iTunes settings intact. Go to Settings > iPod > EQ and tap Flat.

Turn off 3G: Using 3G cellular networks loads data faster, but may also decrease battery life, especially in areas with limited 3G coverage. To disable 3G, from the Home screen choose Settings > General > Network and set Enable 3G to Off. You will still be able to make and receive calls and access cellular data networks via EDGE or GPRS where available.

Turn off push mail: If you have a push mail account such as Yahoo!, MobileMe or Microsoft Exchange, turn off push when you don’t need it. Go to Settings > Mail, Contacts, Calendars > Fetch New Data and set Push to Off. Messages sent to your push email accounts will now be received on your phone based on the global Fetch setting rather than as they arrive. If the global Fetch setting is set to Manually, you will not be able to locate your iPhone using the MobileMe Find My iPhone feature.

Yes, unfortunately the battery drain IS that bad 😟 I appreciate all the suggestions (see below) but honestly NO ONE should have to go through this much effort to make a device work as intended. Boo to Apple on this one.

Just to re-iterate.. Airplane mode was ON and I did NOTHING other than open cal <exit> then open camera <exit> and then same for settings so that I could turn on airplane mode.

Otherwise...
Bluetooth is off (always has been)
All email is (Pull Manually) not push
All notifications are off
I did have 3G turned on but I had airplane mode on so it wasn't doing anything.
I -did- find another post that suggested turning off facetime option might help. I've now turned this off and am waiting for phone to re-charge.
I turned off automatic on the brightness control but as I left the phone face down on the desk in the middle of the night I doubt it kicked the brightness up - but will see anyways.
I also don't apply EQ and wasn't even using ipod app

Hi! I'm new in this forum, and the english is not my mother language, so forgive my mistakes 🙂

I have an Iphone 4 with 4.2.1, and I have the same problem with battery draining. Every 5 minutes or so, without doing anything, the battery consumes 1%. I have reseted the settings, turned off the notifications, logged off the game center, etc... and the problem persists.

I have disabled the Find my Phone, and the battery then consumes 1% each 11 minutes.

The one and only thing that has stopped the crazy consumption has been... turning off the WIFI. In my home there is a poor 3G coverture, so I connect to my home's WIFI. I noticed that the Iphone disconnects from the WIFI when sleeping but, somehow, it stills consumes a lot of battery. Without the WIFI, my Iphone has consumed 1% in a whole night.

I have tested with some configurations in the router (WPA, WEP, etc...), but it's all the same.

I'm thinking in downgrading to 4.1. I don't want to jailbreak my phone, only to have a WIFI connection without the battery problem.

Try to turn OFF 3G, see if it makes a difference.
(even though, Air Plane Mode is supposed to disable 3G, but doesn't hurt to give it a try).

To Nulheim:

Install this * http://support.apple.com/kb/TS3398* and reboot your iPhone.
See if it makes a difference.

Is the bluetooth a big drain?