One iOS 6.0.2 updater said that "I can usually get through a day with about 75 percent of my battery power remaining. Today I've gone through 90 percent and I've done nothing special with it."
Another said: "Today I barely used my phone at all, and I noticed I was down to 40 percent after 3 hours of being off the charger. This is a significant change in battery drain."
A third commented that "before with the 6.0.1 I didn't have any kind of problem with the battery, I could have my battery full charged without doing any use of the iPhone 5 the whole night keeping 100 percent. But this morning when I woke up the battery was in 91 percent obviously without using the iPhone during the night."
TidBITS authors Adam Engst and Michael Cohen speculate that the problem may be triggered by a change in the Wi-Fi behavior in iOS 6.0.2. Specifically, the new OS seems to have increased the number of Wi-Fi checks it performs in order to resolve the previous wireless connection issues, according to MacNN.
Reports of increased battery drain seem to be a common complaint each time a new version of iOS is released. But as usual, the problem this time is far from universal.
Some people commenting on the TidBITS story say they do find their battery draining faster, but others say they've seen no problem at all. The iOS 6.0.2 update was rolled out only to the iPhone 5 and iPad Mini, which also limits the number of users potentially affected.
CNET contacted Apple for comment and will update the story if the company responds.
Comment from Batterybay.net staff:
The drainage of the battery life on iOS device may due to the demanding on system performance required by iOS to maintain its smooth and cool look functioning. Pushing all those parts of the device to perform the maximum effect would easily drain out the battery. Unfortunately, users like us cannot alter the operating system to set something for prevention of drain out. We can only hope Apple Inc. can fix it in the next update.