A week or two ago my coworker had a problem with his iPhone 3G: it wouldn’t hold a charge and would constantly just get warm (almost hot). It would hold a charge for less than a day and then die.
My phone, an iPhone 4, started having the same problem on the bus ride over to the Tahoe offsite. I was going down a percent of charge every 4 minutes or so… That’s 15% an hour. It might’ve been even more. I was going from power outlet to power outlet. The. Like John’s phone it was also getting hot.
Whenever you get to a problem you have to start eliminating possible causes.
Since it was getting hot it probably wasn’t the battery. Something was dissipating the heat. Most batteries degrade over time, not kinda work. If the battery had an internal short it likely would explode.
The next thing I tried was quitting the background applications. This seemed to solve the problem for a short while then it would come back in a little bit. The only app I knew of that would do that is the mail app. My hypothesis is that the mail app was causing some issue.
To test it I deleted my two mail accounts: my home Gmail and my work Exchange.
It stopped dropping charge!
It was something with the email app that was causing the problem.
Of course I need email so this wasn’t a good state to be in.
First I added the Gmail account. Things were still good. Next I added the Exchange account. Things were still fine.
The thing I’m guessing is that the configuration for one of the accounts went insane and it was constantly checking for mail.
If you’re having the same problem, this is something to try out… You might fix your phone without any real work!
Update: Before all this I tried to do a power cycle and a hard-power-off/on cycle. Neither worked. My co-worker John even tried multiple restores and it didn’t help.