Just got a 2nd hand Dell D400 which im very happy with, but... as expected the battery life is poor (an hour). I have been looking online ebay) and seen batteries with capacities of 1900mAH, 3600mAH and 3800mAH. I believe the battery i have on the Dell is the 1900mAH and im also guessing its the standard battery. My question is... if i purchase the 3800mAH what kind of battery life should i be expecting on average If im getting about an hour on the standard 1900mAH and the stated battery life (taken from kelkoo ) is 4 hours. Another question... does the 3800mAH weigh more? and is it physically bigger?