hi every one
when i first got HP probook 4540s it got me 2 h 30 min in the beginning but when i understand this computer it got me over 5 hours in video time (to hell with tablets)
first you should know that some models of it like mine has 2 graphic cards , one is intel built in the prossessor (it won't use extra power )
and the other is high radeon (1 or 2 gig memory) whish take the life battery almost half
first you should install the full drivers of it so if any hardware is not used it will be auto off
install the amd catalyst in win or linux
choose the intel graphic card as the default (no game refused to work on )
use hp power manegment for win 7 (available with the drivers in thier page)
or use jupitor and some power saving hackes (google it) very easy to be done for linux ( i use ubuntu 12.04 32 bit )all drivers ok (but the fingerprint which is ok in suse)
i have almost 5 hours on win 7 64 bit in the lowest screen brightness even with movies on
i have over 5 hr 15 mins on linux ubuntu 12.04 LTS 32 bit in the lowest screen brightness even with movies on
by the way linux is very stable , no need to reinstalls , i am writing from it now which is over 4 month's now is better than the first day i installed it
some thing else i am using it mainly connected to lcd tv throgh hdmi when ac on while labtop screen is off (one time when the electricity is off ) when i unplugged it after a while from the powerless tv i saw 7hrs (i don't know is it real or stupid assuming time) you can try it and tell
sorry if any english mistakes as i am from egypt and my main language is arabic
thanks
i hope it it's usefull