How to make a pandora's battery without pc!

[Ale152]

I was thinking about something...
The psp phat battery has 3 contacts, +, -, and another one for system information about the battery charge (i think...).
For make a pandora's battery, the psp acts on this pin, becouse it can't act on the + or - contacts for programs it...(i think!)
So, to make a pandora's battery, the psp just send some impulses on this pin.
If i send the same imputs with the data out contact of a USB cable (or a serial cable), can't i make a pandora's battery with the pc?
Thank you for answer!

[MattZani]

its already been done, you just cut a pin on one of the chips.

[Ale152]

oh no, i'm not talking about how make a pandora's battery via hardware modify, but how modify a battery via pc, connecting the battery to the pc serial port...