Oh, it’s definitely an issue. And when MMS gets enabled for everybody, it’s going to take an even larger hit.

And people wonder why Apple doesn’t enable background applications?

Here’s what I’ve noticed since the 3.1 upgrade. If I’m at work, which has extremely poor cell service, my battery barely makes it to the end of the workday, even if I hardly use it.

But if I’m not at work, in areas where cell reception is relatively decent, the battery will still be 80% full by midnight, with roughly the same amount of usage.

It appears that 3.1 might be making the phone expend a lot more energy trying to lock onto the nearest cell tower. If it doesn’t have any trouble doing so, battery life is excellent.

I’ve actually noticed a major IMPROVEMENT with battery life. The upgrade did require me to restore from a backup, so maybe that cleared up the problems I was having upgrading to 3.0. I noticed a big drop in battery life with 3.0, and a major IMPROVEMENT after upgrading to 3.1 and doing the restore of apps/data.

My suggestion. Restore your iPhone after upgrading to 3.1 - this may clear up some issues. I have a feeling that some apps that are not fully compatible with 3.0/3.1 will perform better after the restore.

I agree with Steve, It happened to me as well and done the same procedure after the restore once updated to 3.1

My clearout iPhone 2G (£169 in April 2008, pre-3G), has been pretty much the same throughout it’s life, a slight dip during 2.0 to 2.1, but otherwise the same as ever - 3.5 to 4.5 hours usage, with around 2 to 4 days standby.

I mostly drain it playing games, streaming internet radio over WiFi, as well as moderate SMS and calls. 3.0 and 3.1 have been pretty much the same for me as have most of the previous firmware iterations. Every update is a restore job for me as I also Jailbreak, so that could be a factor.

Mine’s an o2 unlocked to Orange UK, if I’m in a low signal area, which can happen when I swap in a Virgin SIM for the cheap data, the battery gets creamed, pretty standard behaviour. You’ll also probably notice your phone getting a bit warmer, even in standby, when the signal is crap.

I know that the the battery life got worse.  The issue is not how bad the iPhone battery life is but what you are going to do about it.  Get an external iphone battery pack for backup.

Thanks for this informative Topic
Keep it up

I’d been having the battery life issues for a couple of days with iPhone 3GS too. The battery drained as if the phone was in use even though it was in sleep mode. I upgraded to 3.1.2 and hoped it would solve the problem, but nothing happened. I tried everything - turned off location services, push email, 3G when i wasn’t using the phone etc.
After trying to troubleshoot long and hard, turns out it was an app that was draining the battery life, even though i was not using the phone.
In my case, it was a game called Topple. The minute i deleted the app, everything started to work as normal again! It may not be Topple that specifically causes the problem, i believe it is some kind of compatibility issue with apps of the same kind. So suggest you start by deleting your apps one by one and observe which one may be causing the problem. Good luck!