General :: Laptops Battery Life On Compared To Windows?

i recently purchased my second laptop, primarily for linux. When i chose it, my main concern was battery life. Just to make a side note. When i say battery life, i mean how long the computer takes until the battery goes flat. Not how many years/ect it takes till the battery will no longer hold charge.

My new computer claims to be able to get 10 hours. Although it's a bit off, i get a satisfying little bit over 6 hours, from full charge. This is running Windows 7. I couldn't wait to put Linux on my new computer, i have, but it just isn't satisfying because i only get about 4 hours while running linux, tried three different distros, and all roughly the same.