I have the original RC powered by AA batteries. Recently while I was flying, the RC began beeping non-stop. Nothing bad was happening on the screen, so I just assumed it was the AA batteries that had reached a low threshold of some sort and I got my Phantom back to me in a hurry and landed. (I usually change the AA's out every 15 flights or so, even though a battery checker shows them as still being good.) I popped a new set of AA's into the RC and it hasn't beeped since. Does anyone know about how much time one has before losing control signal once that RC battery warning beeping starts? I don't recall reading anything about that.