In the phone dialer enter code: *#301279#Battery Calibration
Click  CHANGE HSPA REVISION
Click  HSPA OFF
Remember, always flash with a full battery.
USE phone heavily. Use it till the system turns OFF automaticallyOther Modem
Turn OFF phone
Charge till it says it is FULL
Start phone in RECOVERY Mode
Select Advanced CWM Features
Select Wipe Battery Stats
The JPD modem has been reported to give better battery life.Gallery Issues
Thumbnails and some database's could get corrupted making the media scanner running berserk, resulting in battery drain.
Delete the following:
dbdata/databases/com.android.providers.mediaI have created a CWM script to do this for you - Gallery Cleaner
And clear the thumbnails folders on sd cards.
One technique that has gained popularity in the user community is "bump charging." To bump charge a device do the following:
Turn it off completely50% Battery without Signal
Plug it into a charger.
Wait until the green battery sign says 100% . DO NOT turn the device back on.
Disconnect and immediately reconnect the power cord. (The device will now accept more charge before saying it is full.)
Well Known Froyo bug that started from the very first firmware release shows phone as 50% time without signal on cell standby when you check in Settings > About phone > Battery use
Apparently this can occur anytime after unplugging your phone from charge so I always do 2 things to fix this and so do many other users.
Turning Flight mode off and on.Other Resources
In the phone dialer enter code: *#*#4636#*#* > Scroll down a bit >
Select Phone Info
Select "Turn off radio"
Select "Turn on radio"