Goce from mp3Car will walk you through the steps necessary to power your laptop using unregulated ~6~24 volts with only the p2140 and the wire your laptop power adapter came with.

-For this project you need the following materials:
-p2140 and 8pin molex output harness
-Wire strippers 14-22 gauge
-Bench battery
-Shrink tubing and heat shrink tubing gun OR electrical tape
-Solder gun and non leaded solder
-laptop and its power brick
-knife or scissors

To finalize this project you should do a continuity test on the stripped wire to find out which is positive and which is negative. Then you can twist and solder the p2140 output wires to the cut laptop brick wires. Turn it on to test it one more time, and then plug it into your laptop to test.