|Did you purchase original battery or replacement?|
Have you charged it for 16 hours before using the laptop on battery only?
Have you checked the contacts on the battery and the laptop to make sure they are clean and bright? A pencil eraser may help if mild tarnish.
Did you purchase from a reputable dealer, ebay, or online site selected at random?
You have to be a little bit crazy to keep you from going insane.