iPhone battery problem (and solution)

When my iPhone's battary totally died (partially because I wanted to run it down, as often recommend) I charged it to 100%. To my great surprise, only a few hours later, without much use, the battary was down to 65%! I charged it again, but it started to leak juice again. I keep all battary-intensive tasks at a minimum, but I checked and rechecked the setting several times. Nothing!

Here is how I solved the problem. I enabled airplane mode for just a few seconds. I charged the iPhone again. The problem dissspeared. The phone is holding the charge much better. Not being an Apple engender, I cannot explain all this. Maybe there is some process that was lingering in the memory. Anyway, from now in I just might switch to airplane mode every once in a while.