Heres 1 from another board:
""So, you are having trouble with your battery seemingly draining too quickly, especially after having flashed many ROMs/Kernels/etc...
It is possible that the problem (or part of the problem) is not necessarily the phone using too much power. If this is the case for you, you should see some results from doing the following:
1. Connect the phone to the charger with the phone powered on, and allow the phone to charge until it shows 100%
2. Disconnect the phone from the charger, and power it off.
3. Reconnect the phone to the charger with the phone powered off, and allow the phone to charge until the battery indicator shows 100% (you can use vol-up/vol-down to make the indicator come back up when the screen goes to sleep).
4. Disconnect the phone from the charger and power it on.
5. Once the phone is powered completely on, power it off again and reconnect it to the charger until the battery indicator shows 100%.
6. Disconnect the phone, power it on, and use it.
You should only need to use this sequence one time.
Hope this helps.-Joeybear23"""