Dear Lawrence,
I found this thread while investigating about my sudden battery draining problems. I have had an iPhone4 for about a year with no problems whatsoever. I use all sorts of notifications, locations services, and things that typically use up the battery, like 3G data download. Always had between seven and eight hours of phone usage, and on average had to recharge it every other day (this oviously depended also on how much I used the phone). I set it up to wi-fi sync with itunes when system 5.0 came out, updated to 5.01 (or whatever) with no problems and no change in battery usage. Suddenly, few days ago I noticed the drainage. I know it could be many things and decided to simply restore and backup from restore. It is unclear what it did, because the day after I was on a trip and used the iphone a lot, in one day I had pretty much seven-eight hours of usage time on 3G. That heavy usage might have masked a battery drainage. One easily notices an abnormal drainage whan one does NOT use the phone. At any rate, the following day (back home) the problem was clearly visible. It's possible that restoring from backup did re-create the problem. Maybe.
When I read this thread I also went to the first link you provide, and that link sent me to another one. I noticed that my console app was having lots of messages from usbmuxd regarding attaching and detaching the iphone (and ipad too though, and the ipad does not seem to have the battery drainage problem, although it is more difficult to say, because you do not get the stats you get for the iphone, and the ipad battery lasts a lot). Anyway, I decided to do two things. Delete three of my four email accounts, and turn off the wifi syncing with itunes. rebooted and quit itunes.
battery went back to its previous good performance. then i added again the three emails account. battery still strong. then i re-started the wifi syncing yesterday. battery still strong. today i also restarted wifi syncing for the ipad. suddenly i got battery drainage (on the iphone!) again. since i don't believe in magic, i think this is purely coincidental. consider also that i had wifi syncs on both iphone and ipad since 5.0 came out with no issues until last week this battery drainage appeared.
the fact that the battery drainage came out again in a few days is concerning. it's possible that deleting the email accounts again might fix the problem, but how is it possible that i never had these problems for a year, and suddenly it happened two or perhaps three times in less than two weeks? (it is unclear if my battery went temporarily back to its previous performance after the restore, because of the confound of the trip and its related change in iphone usage).
some suggest a reset network settings, but i don't see how that can help. after all, until few hours ago, my iphone battery was going strong with those network settings.
the other thing that puzzles me is why the process that drains the battery does not stop when you reboot. rebooting is of no help at all. how could that be? i thought that rebooting would kill any process on the phone.
i don't like to do things that do not have a rationale. until few hours ago i thought that my problem was a new problem linked to wifi syncing. i now think it's more what you say, associated with emails. but what puzzles me is that after i solved it, it came out again in a couple of days.
any tip?
thanks
(and my apologies if this is too long, or too confusing, or most likely both) 🙂