*Depending on your laptop warranty this may void it!*
Before reading this Instructable, I recommend reading this one first!!
Step 1: Remove the power
After you have got the battery apart you will find around 9 battery cells depending on the type of laptop battery. You will need to rip all these chunky batteries out, making sure not to rip the wire leads to the batteries off the circuit board (pic. 2)
Step 2: Source and improvise the power
If you are using two batteries you will need to connect the positiver (red) of one battery to the negative (black) of the other battery.