dv9000 battery discharge when turned off

I bought an HP dv9000 series laptop a little over a year ago and I've had this problem since day one. The battery will discharge 20% or more per day when it is stored in the laptop turned off. I can fully charge the battery, unplug it, leave it in the laptop for 5 days, and the battery will be completely dead. When I fully charge the battery and remove it from the laptop for the same period of time, there is almost no battery loss. I know the battery will discharge slowly when in the laptop due to it being connected and basically being in a stand-by mode, but 20% a day seem a bit excessive. Anytime I pack up my laptop I end up taking the battery out and it's kind of annoying. Temperature is not an issue; my house is usually never over 70 degrees.

Any ideas?