The Guardian reports that a number of users of the new iPhone 3G are reporting that it seems to get unusually hot. The story is here. These are so far anecdotal reports; no testing lab has weighed in on the story yet, so far as I can find out.
If I had an iPhone, I would view these reports skeptically, while staying alert for updates.
Apple has posted an article here on the iPhone’s internal temperature-sensing mechanism. (I love the way the iPhone in the illustration refers to itself in the third person, much as Louis XIV of France might have done).
Here’s an excerpt from the Guardian’s article (emphasis added):
Even so, a number of users have said that the phone gets significantly hotter than the 3G model that was released in 2008. Melissa Perenson, a reporter for PC World, said that she noticed that when it was plugged into the wall to recharge that it became “Very, very hot — not just on the back, but the entire length of the front face, too. I was using a game, and then later the Web browser for reading the news about Michael Jackson, all over a Wi-Fi connection while plugged in. And in those circumstances, well…toasty doesn’t even describe how surprisingly hot it got. It was too hot to even put the phone against my face.”
The clue may be that the iPhone’s new battery becomes excessively hot while it is charging, especially if the phone is new and the battery has not been through a number of recharges.
As far as I am concerned, what constitutes “excessively” is a matter of opinion and we humans are not very good at measuring stuff impressionistically–that’s why we keep inventing different types of meters.