iPhone battery completely drained overnight; no idea why

[luminosity]

Hi all. I picked up my iPhone this morning after not having used it since the afternoon yesterday (when it had close to a full charge), and the battery had somehow completely drained.

Any idea how that could have happened?

[dws90]

Was Wifi on? 3G? Location services?

Draining the battery when left on for an afternoon then overnight sounds about right to me. Even if you're not using your iPhone, it's still doing things (checking email, checking for text messages, etc.).

[ttull]

the last 4 nights i have gone to sleep with battery fully charged, TURNED OFF wifi-fi, always have it on push (vs auto check for email) AND I even turned on the Airport mode just to see if it would change anything, and, it was dead each morning when i got up. today was so bad it read 3:08 AM (and it was 7:08 a.m.) and Dec. 31, 1999 when it is clearly Jan. 14, 2009.

any suggestions, i have tried all the tips on the apple web site.