Alas, my experience with DELL batteries has been the same as echoed here.
90 min max, especially for the Latitude D Series, especially after a few
months. Of course my experience with the HP dv Series yields the same
We have also replaced a lot of power adapters on the DELLs, as the cable
around the head seems to stress easily and eventually stop working - not
great for school environments where laptops suffer multiple users and lots
of use. Also, interestingly, DELL released both a 60W and 90W adapter, and
I have yet to find a good use for the 60W one.