Mine cost $190 but with a bit of planning you can definitely do it for less than $100.



In the quest for a longer cheap lasting laptop battery.



http://www.geekzone.co.nz/MrWestie/7032



 



That was my 2010 new years eve, what did you do?



Capacitor


Paralleled MOSFETs


Control board


Cable ends


Test Setup



It works



Test Battery pack