LG Optimus battery drain

[Guest kfcisntchicken]

Hi all i have a problem with my gt540 which means that when i have charged it the battery level will slowly deacrease for about 3 hrs then in the 4th hr will drop rapidly to 15%. my phone has all bat saving options turned on so thats not it and the wifi is always off as is the gps and the brightness is down but even if i turn it off at 15% it will not turn on it will just come up with the lg logo and then go black. Saying that when the phone is connected to a charger performs faultlessly and does not do anything it shouldnt. The phone is about a year old and i was wondering whether the battery might be the issue. If you guys could resolve this it would be much apprieciated. Thank you

-kfcisntchicken

--------------EDIT----------------

This phone is running official 2.1 software and no cyanogen mods have been installed.

Edited September 22, 2011 by kfcisntchicken

[Guest darshans996@gmail]

same here

[Guest professionalnoob]

download batter calibration and recalibrate it when fullly charged