I have had my P800 for 1.5 years, and all was well until the last 4-6 months. What I find on my unit is : when looking at the connectors where the battery goes. that some of the contacts have lost their resiliency - tension. So when you view the location where the battery is placed, with the battery out of the p800, the same side where the stylus goes, the left most contact seems to have lost its tension and sometimes touches the contact to the right of it. When this happens, the battery drains very fast, like in 2 or 3 hours. when i am able to keep the two apart, the battery might last 6-10 hours- depending on usage. I am going to send it in for repair. As i love my P800 and no other unit out there compares - with the exception of the P900. Hope this helps you - I will post another message after repairing the unit to inform you of theory.