There are numerous threads on this problem here... However, he said that it drains the battery only when wifi is running.
It drains real fast when using wifi. This I can kind of understand, so I have tried putting the N800 in offline mode and locking the keys and screen. Even after doing that, if I turn the N800 back on after a few hours, It show a very depleated battery, at best, and sometimes it just will not turn back on unless I charge it up again.