updated 12:55 am EST, Tue November 15, 2011
5.0.1 iOS update didn't entirely fix the issue
A test conducted by Adrian Kingley-Hughes at ZDNet appears to prove that the battery-draining issue that is affecting some iPhone 4 and 4S owners doesn't have it's root in hardware. Using a pair of identical, purchased-on-the-same-day iPhone 4S handsets, Hughes and his developer tester were able to make the battery issue "jump" from a handset that had the problem to one that didn't by swapping backups.
The problem, as outlined by many support forum posts, causes the iPhone to drain the battery more rapidly than normal when it is supposedly idle. Users who are trying to diagnose the problem are unsure if it is caused by a malfunctioning setting, an OS problem or a popular app that is misbehaving, since not all users are affected by the issue.
The test, which only involved two identical handsets, isn't conclusive scientific proof of a lack of a hardware issue but does suggest the problem is software-based, giving hope that Apple will eventually be able to solve the problem for all users via a future software update.
For the test, both handsets were running iOS 5.0.1. One was experiencing the battery-drain issue, the other (used by the developer as a "testbed" for app development) was not. Both units were factory-reset, then recovered from the other phone's backup. As predicted, the problem jumped from the phone that had the problem to the one that didn't, while the one that previously had the issue no longer did.
To illustrate how noticeable the problem can be, Hughes reports that a typical iPhone handset, when idling overnight, could be expected to lose between three and four percent charge normally, but an iPhone with the battery-drain issue might see 15-20 percent loss in the same conditions. Apple's 5.0.1 update fixed battery issues for some users, but not all. The company continues to work on a further fix. [via ZDNet]