5 - 30 мин.
My iPhone 4S was always charging everywhere I went.
The repair was very easy and quick with the tools provided by iFixit. Only 3 screws and some glue. I did it in a few minutes.
Just do the repair in a light room because the screws are so tiny. And have fun. The best part is to turn on the phone and see that it worked. :-)
iPhone 4S Replacement Battery
iPhone 4 Replacement Battery
iPhone 4 (GSM/AT&T) Vibrator