I've got a HP Envy M6 1178ea notebook which has a battery life of about 6 hours when running on Windows 8. I recently installed Ubuntu 12.10 (quantal) 64-bit and the indicator shows a battery life of just 2 hours when fully charged. Moreover, the fan keeps running continuously, which is pretty annoying. Is there a way to fix it?
Your laptop has a pretty neat graphics card. Probably, Ubuntu is continuously powering the device which makes your fan go crazy and drains your battery.
I would suggest to install AMD proprietary drivers from their website. These drivers include fan control and will be less generous in terms of power supply to the graphics card.