What is the meaning of uptime?

[pms]

What is the meaning of uptime? When does it get reset?

[Eitel]

It means the time that the PPC has been running on battery power.  It resets when you start charging it again.

[pms]

That what I thought!

But it only resets if the unit is on while it is being charged! If you fully charged it but never turn it on while it is plugged in it will never reset......