You can enable battery % on ipod touch 4g without jailbreaking it you can use backup bot for itunes. Thats how i enabled it on mine. Step 1: goto http://www.icopybot.com/ibackupbot_setup.exe download and install it if you have windows. Step 2: Next create a backup of your device in iTunes and then CLOSE iTunes (or else you may run into problems later on) do not lock the backup with a password. Step 3: Open iBackupBot. Click the backup you just made Next click "Path" to sort by Path. Step 4: Look for Library/Preferences/com.apple.springboard.plist and double click it. On the registration screen that comes up, hit cancel. Step 5: Find <dict> and create a new line after it. Then add this:
<key>SBShowBatteryLevel</key>
<true/>
Step 6: Hit CTRL + S or just the save button at the top left corner of that editor window. Now close the window.
Step 7: Right click that same backup you just edited
Step 8: click restore
Step 9: Done! If you don't see the changes, reboot your iPod.
Enjoy I hope you found this useful!