Hi! I have bought my Prs-650 few weeks ago. I am using it intensive, and battery goes to zero after 3 days

(~1500 - 2500 page turns). Is it normal? And another thing: my device is charging from USB only in 2 hours

( manual says that it must charge in 3 hours ), I've tested it on several PC's. I am not using any memory cards, and I've tried to charge in both power off, and stand-by modes. I've also tried to format memory: no results. I have not yet tried to do hard reset. Please

.