Hibernate Doesn't Work :(

hey guys, i have the newest macbook pro and have had some issues with the sleep/hibernate feature, i don't care so much for sleep but i really want to be able to hibernate my macbook pro so it doesnt use battery, so i read somewhere that i needed to use a 3rd party program to use hibernate so i downoaded smartsleep and have set that up, however it doesn't always hibernae and will sometimes sleep the laptop which can be annoying after i've put it in my bag! anybody know a better way?

thanks.