iOS 4 - battery drains much quicker after update

I was having a severe battery drain too after the update so i turned off all my location services but it continued. Then i read that gmail was having problems with the new OS and it was causing problems with syncing. So what i did was turn off my gmail (exchange) account and reset the phone (I also turned back on the location services). This seemed to have worked for the most part. The battery still drains quicker than before the update but at a much less rapid pace. Before I did this, i was losing 20% an hour (with NOTHING running), now I've had the phone on for about an hour after full charge and i've only lost 3% (however, before the update, i'd still be at 99-100% since i'm doing nothing with the phone). So if you have a gmail account, maybe turn it off until Google fixes the problem (not sure if they have yet, havent checked). Hope that helps at least a little.

Absolutely I see a significant battery drain with iOS 4 on my 3G. I usually get at least a day and half with a full charge on my normal usage. I turned down the brightness as low as possible. After the upgrade, I see the battery went down with just 10 minutes of gaming or browsing. It never was that bad. Hope this gets fixed soon.

This draining fast is ridiculous and we expect better from apple being that it is a premium brand. We pay through the butt for them and there is no way that the beta test didn't reveal this issue. It MUST be addressed ASAP I'm going through 10% battery an hour on standby.

Same problem on my 3GS. Losing about 1% per minute with light use.

Everyone should tell apple, using their feedback form, http://www.apple.com/feedback/

I upgraded yesterday, last night, set my alarm for this morning and it didn't go off. Battery was dead and phone turned off. It was at 96% when I went to bed and battery was dead within about 7 hours when alarm was supposed to go off. No battery issues before upgrade. I had even thought that I should wait a month or two and let others find these issues before I upgraded, wish I had now...

I've had no problems so far with battery drainage since updating but did a few weeks after i brought my 3gs, 100% to 0% in 1 hour. At the apple store, i was told that the problem might be, a app is still running despite being closed and to try restore it back to factory settings using itunes. I try this and have had no problems since.

iPhone 3Gs. Battery totally drains overnight since upgrading to ios4. This needs to be fixed ASAP.

I am having the same issue, upgraded 3GS to os4 last night (6/23/10). This required a restore of the phone, not sure if this is by design. Now this morning battery is down to 15% after 5 hours of use. Also noticing that the phone is very warm on the back. I never had a battery issue prior to the "upgrade"

What I want to know is, has apple even acknowledged this completely unacceptable problem and doing anything about it or are they ignoring it??? Would be nice if they acknowledged it at least.

Same problem battery goes from 100 to 20 percent in roughly 3-4 hours - and this is with the phone locked and nothing running on it. Between this and the problem with AT&T I am soooo tempted to switch back to Verizon and get an Android phone.

My drain isn't as drastic as some here, but it is a 30% increase of battery drain. I used to only lose about 20% of juice over 10 hours, with iOS 4 I am losing about 60% over the same 10 hours.

I notice every app I open, stays open. I thought they weren't to be running in the background or when the phone is off, but something is draining the juice.

I could go a day and a half with my 3gs with normal use (5 email accounts) 3G and wifi on (wifi on and off) the only setting I had before was fetch mail every hour and brightness set to 20%.

Now after the upgrade the battery dies by 12 PM. and while on talking on phone it gets really hot at around 30 minutes of use. only changes an extra email account added.
Then tried rebooting. No change.
let it die completely and recharged fully. No change.
Disabled wifi totally. slightly better.
Disabled 3g. slightly better performance. (lasts till 2 pm)
Also I have to keep killing the apps in the multitasking mode.
This is very frustrating. I wish it was easy to go back to version 3.

Ditto on the high battery drain also.

I just read a news report on another web site that when the mail app is exited and residing in the background (multitasking), under iOS 4 it will now frequently poll all of the registered email accounts EVEN when the default mail settings are set to poll only every 15 minutes or longer (i.e. mail push off). It's possible this could account for some or all of the high battery drain we're seeing.

The only way to stop this behavior is to force the mail app to quit from the multitasking menu (hold the mail icon in the multitasking menu until it wiggles and then click the red minus).

I've killed all background apps (especially mail) and am watching to see if this improves the battery drain.

Best regards,

JL

I read on the following web site that apparently there's a bug with tethering and sometimes it gets stuck on and you need to go in and cancel it. I don't know if that helps or not since the tethering setting always "spins" if the settings app has been quit after it was launched (i.e. removed from background).

http://appletoolbox.com/2010/06/iphone-battery-drain-after-ios-4-0-update/

Personally after first installing it I was getting rather good battery life (only drained 2% overnight). Today I topped it off a few times and the last time it died at about 4 hours of usage (8 hour total). When I tested it, the battery drained 2% during 40 minutes of standby with 2 minutes of reported "usage" during that time.

Message was edited by: Morac

Yes, check the tethering option. See if it's on or not.