Replacing the battery
Your Treo™ 650 smartphone comes with a replaceable battery. Be sure to use a replacement battery that is compatible with smartphone.
1.Press Power/End 
to turn off the screen.
2.Press the Battery Door Release button and slide the battery door downward to remove it from your smartphone.
3.Place a finger in the notch next to the battery and lift the battery up at a 45 degree angle.
4.Align the metal contacts on the battery with the contacts inside the battery compartment.
5.Insert the battery into the compartment at a 45 degree angle, pressing it into place. Slide the battery door onto the back of the smartphone until it clicks into place.
6.Wait for your smartphone to turn on, and then enable the network time or set the date and time when prompted.
Be sure to dispose of your old battery properly. In some areas, disposal in household or business trash is prohibited.