A Bluetooth headset is a small device that fits behind the user's ear, allowing him to have a hands-free cell phone conversation. Most Bluetooth headsets come with a small charger, but as with any battery-powered device, the battery eventually stops holding a charge. Replacing the batter on a Bluetooth is very simple.
Consult your Bluetooth owner's manual to determine the location of the battery door on your headset.
Pop open the battery door on your headset with your fingernail, and tip the Bluetooth headset over so the battery slides out. Note the end that came out first--the positive or negative end. Discard the old battery.
Insert the new battery with the same end facing outward. (Some headsets have markings on the battery door that specify the direction.)
Snap the battery door closed.
Put the headset on the charger and leave it there until the indicator light flashes that the battery is fully charged.
Consult your Bluetooth owner's manual to determine the kind of battery you need for your model of device.