I had a situation where my iPhone 4s was left outside and the battery got cold and drained itself. I tried "Find my iPhone", but it did not work because the phone was completely dead. It was a fluke that I found the thing. It had fallen in the snow when I was getting out of my car. Symptoms that I saw: Phone was completely dead. When plugged in, it just showed the outline of a battery with a thin red line basically showing no charge. I tried rebooting, but it would not respond. I finally went back to "Find my iPhone" after it had been plugged in for about a half-hour. Sending a signal from "Find my iPhone" finally brought it back to life. This is not a big story, but I was not able to find a cure online. The next time somebody is looking, hopefully this will help them out.