Epson 4SLC2-50 - Manual (Page 56)

Once your computer starts beeping, you have approximately two
minutes to save your data. If the batteries run out suddenly, you
will lose any data you have not saved.
Turn off the computer before replacing the battery pack.
Otherwise, you will lose data, and you may even damage the
computer.
Using the Suspend/Resume Switch
The suspend/resume switch provides an efficient way to save
battery power. This switch is located on the top left side of the
computer.
Powering the Computer 3-7