Hi there, I know that when you're running out of battery, there is the first message to tell you that there is only 20% available and then 10% if you don't plug the phone in to charge, until you run out of battery. Sometimes, you are engaged in a long conversation and you don't realise how much battery you've still got, and the call obviously fails as there is no battery power anymore. We all know that it takes a while for the phone to turn on again so that you can use it. By this time, you have already lost the momentum of the conversation. It happened last night, and I think Apple should add a warning beep to tell/remind you that the battery is running out. What do you think?