as its already been asked by Anthony Cardenas,it would have helped if you had of said what model.
but this is all i could find out.
Try another USB cable.
If that doesn't work then the headphones may be faulty. Do they have easily replaceable batteries?
It's worth finding out if the batteries can be changed
I had the same problem with mine, I'd not used them for a few weeks and they wouldn't
charge. At least thats what I though.
Try leaving them on charge on the PS3 for a few hours regardless of charging light.
Also try pluging them into a PC with the wireless dongle, you're PC should recognise them as speakers and mic, if that works at least you know the headset is fine.
like i said this is all i could find on the internet so not sure if its any help to you,if not sorry for taking up your time,and i hope someone does get to help you out with this.
or see if this link helps you out.
Ps3 wireless stereo headset wont charge Google Search