i am getting 2.56 v out from the n900 , on 80% battery , so i think some people may get power leds to light on some devices , but they won't be recognized by the system , since the controller/processor on that device isn't actually on , i think minimum voltage is 3.3v , i will charge the battery fully and hope to get more than 3.3 v , BIG THANKS to all developers .in future i hope we can get 5v out.

[EDIT]the above is wrong , i had a faulty cable , the output is 5v .