Unfortunately it is not defective, it's standard!
I get about 2hrs on my vaio ns20, it was almost three when brand new.
On my old Vaio I got 3hrs but after a year with two batteries it reduced to 45mins on one battery and 1.5hrs on the other.
With all the cheap materials they use and inflated prices with batteries that explode, Sony do not make batteries like they use to. Hopefully the next generation batteries will be better.
