The only time my battery drained like that I had inadvertantly layed it on my computer instead of a non-electronic box I keep it on.  When I noticed what I did, I immediately moved it to my usual box, but when I checked next (I don't remember how long later, hours or maybe a day) the battery was drained.  I had just charged it the day before I did this.  
 
I recharged it, and have been very careful not to set it on anything electronic.  And I've had no problems.
 
this is probably a lot of useless info, but I'm wondering if a lot of the people who've had battery issues have been leaving the PP sitting on electronic devices.
 
Or am I way off...........
 
 
AJ