quick note on batteries-
I am using a fujitsu lifebook p series (small) here's what I have found.
Valence N-Charge
Run time with lid open: Just under 3 hours.
Cost: 200$ at Best Buy in Iowa City.
Charge time: Less than 3 hours to get a full charge.
Weight: less than 2 lbs.
Size: slightly larger than my laptop.
Bonus: comes with an extra power cable
Electrovaya Power Pad
Run time with lid open: 120A=about 11 hours 160A=about 15 hours
Cost: 170$ on ebay, about 260$ new.
Charge time: overnight
Weight: about 1.5lbs
Size: same size as my laptop
Bonus: Great for festivals!!
Both of these batteries make models that will fit almost any laptop. Both use your laptops ac adaptor as the charger, except the Power Pad 160A which comes with it's own charger.