Instructions
Use a different USB port. The PlayStation 3 Bluetooth wireless controllers use an included USB cable to charge the controller when it is connected to the system. If there is a problem with one of your USB ports, the controller won't charge. Try plugging the cable into another USB port on the front or rear of the system and then try again.
Keep your PlayStation 3 turned on. Your PlayStation 3 will be unable to charge Bluetooth devices if the console itself has switched into "Standby" power saving mode or is off. Keep your PlayStation 3 on for the entire time that you need your Bluetooth device charged so that the charging can properly take place.
Verify that your device is capable of being charged at all. For example, while the PlayStation 3 wireless controllers have rechargeable batteries the PlayStation 3 wireless remote control uses standard AA-sized batteries. While you can connect the remote to your console via a cable, this will not charge the batteries. When the batteries die they will need to be replaced with a fresh pair so that the remote can continue to operate.