Blackberry RIM 850 Installation And User Manual page 23

2. Once you have removed the battery cover, remove the old
battery and insert a new one. When inserting the new battery,
make sure that the connectors are aligned for the correct
polarity. The handheld will vibrate and beep if the battery has
not been inserted properly.
Note
If your handheld does not turn on after you have inserted
the battery, then either the battery is too low or the internal
lithium battery is discharged. Allow the battery to recharge
the internal lithium battery by leaving the handheld turned
off for 6 to 8 hours. See page 145 for answers to frequently
asked questions about the battery.
Get to know your handheld — Installing the battery
.
Installation and User's Guide
23