The iPod touch, in its default setting in OS4, drains the battery at an incredibly fast rate. This is in comparison to the previous operating system. The drain makes the device of limited usability. You can cure this problem by changing your default setting. This will allow you to minimize this battery drain and still use your device as it was originally designed.
There are a few causes of this drain. With Wifi on the radio connect to the internet every 10 seconds. There is no way to change this setting except to turn the Wifi radio off direct or by putting the device into the new "Airplane Mode" setting which turns off Wifi and all push and fetch features. This cures the problem but its like throwing out the baby with the bath water. One of the best features of the iPod touch is its ability to fetch email and receive push notifications.
So here are my tips learned from my personal experience and confirmed by users on the Apple iPod Discussion Forum
1) Turn off notifications and application location services, under the settings menu, for programs from which you do not absolutely require constant, automatic updates.
2) Turn off the Bluetooth Radio when you are not using it. This can be turned off in the settings menu.
3) Go to Mail, Contacts, Calendar under settings and turnoff the push and fetch features. If you need email fetch set it to either 15 or 30 minute intervals. At thirty minute intervals my iPod touch showed only a little battery while left in sleep mode all night, even though I did receive several push notifications. To reiterate I left the Wifi Radio on all night and the device was not using the new "Airplane Mode".
4) Put the device in Airplane mode when you do not need to connect to the internet. This mode turns off the Wifi Radio and all push notifications.
These setting changes worked for me. By the way, Apple will not let you return to previous versions of the operating system once you have upgraded it so consider carefully your decision to upgrade. Do you really have enough applications to require the new nested folders feature? I like this feature a lot because I have a lot of apps. The send major advantage of OS4 is a unified mail inbox. This is very useful if you have more than one email account. It works just like the "Mail" application on the MAC OX10 operating system. These are the two key advantages of upgrading to OS$ for iPod Touch users. Please feel free to post your comments and questions.
John H. Armwood