Here is a view of the power connector on the computer side, notch down.
It is translated from German.

 8  7  6
 
5   4   3
 
 2     1

Connection descriptions:

1, 2   Operating Ground (GND)
3      Contact of the contactor against ground (normally = out openly), 
       is evaluated by the power pack 
4, 7   Operating voltage (12-16 V, 1.5 A)
5, 8   Charging voltage Akku (18 V, 2.5 A)
6      Ground, comes from the power pack into the notebook.

To consider still another longitudinal diode of the type is 
Erd64m-004 between them with self-'s building charging circuits 
that the connection 5/8 does not hang directly on the Akku plus, 
there is. Just as one should know that against connection 4/7 
constantly the Akku tension rests, only around a further 
longitudinal diode of the same type reduced. This connection 
is connected through also by the main switch in the equipment.