My iPhone is a little over two years old and the battery would not keep it's charge very long. I bought a replacement batter and replaced it myself. The battery charged fine and I can use my phone as long as I want. However if I don't use my phone for about 2 minutes, it will not turn back on. I then just plug it into a power source and it "flashes" on. Then I can unplug it and use it for as long as I want. Also I can make my phone sleep then turn it back on as many times as I want as long as I don't let it sleep longer then a couple minutes. Anyone have an idea?