How to Enable battery percentage indicator on iPHONE 2g, iPhone 3g OS 3.0
VIA SB SETTINGS
The easiest way to do this is via SBSettings. SBSettings is a jailbreak application
that brings various toggle switches directly to iPhone's home screen that are available in the Settings app.
Follow these steps:
Step 1: LAUNCH SBSettings, tap on the More button. This will take you to the settings screen of SBSettings.
Step 2: Tap on "Extra & Options" at the bottom of the screen.

Step 3: Then tap on the toggle button to enable Numeric Battery.

Step 4: Last step is to reboot your phone if it doesn't appear immediately.
VIA THE APP - asBattery
You need to install asBattery developed by Andre Sendowski using Cydia on your jailbroken iPhone.
Follow these steps:
Step 1: Launch CLYDIA and tap on the manage tab at the bottom.
Step 2: Then tap on resources.
Step 3: Tap on the "Edit" button on the top right corner and then the "ADD" button.
Step 4: Tapping on add will open a pop-up where you need to enter the URL of the repository. Please enter http://apt.iphone-storage.de and tap on the "Add Source" button. Please wait for the repository to be installed.
Step 5: Then tap on search and search and install asBattery
Step 6: After asBattery is successfully installed, reboot your iPhone.
Step 7: Now open the app, and you should be able to enable the percentage bar. General->Usage->Battery Percentage) just like iPhone 3GS users.
Please let us know if it worked for you
