How to fix false battery indication on iPhone – I did this after my wife bought a new iPhone 4 to fix her Iphone 3G. Personall I think it was a big scam so she could get a new phone!
Below is how to fix it…
Reset network settings Tap Settings, tap General, tap Reset, tap Reset Network Settings. This will cause your iPhone to restart, and will delete any stored Wi-Fi passwords as well as DNS settings and more. It can resolve signal strength issues in some cases too, but it cleared it right up. It went from showing 10% battery remaining all the time to correctly reporting. I was using the Free Battery Meter to check it since the Iphone 3G only shows a dull little battery with no %.