I got the official Sony headset, and when i connect it to my ps3 in the top right on my screen i get a gray pop up with information.
And the information is: Battery meter, Microphone on or off.
The pop up will be gone in like 2 seconds, but if i press the mute button, it pops up again.
If my headset runs out of energy, it keeps bleeping in my ear and that means i need to charge it.