Poor Surface 2 Battery Life

I just purchased a Surface 2 a few days ago and all has been working well except the fact that I have experienced sub-par battery life well below that than the 10 hours Microsoft advertised. For example if all I'm doing is browsing the web with the brightness turned down to somewhere around 30% I will only get somewhere around 4-5 hours of battery life. I was just wondering what battery life other Surface 2 owners experienced when they first purchased their Surface if it ever improved and what kind of battery life you generally get.