For all people with power problems using Ubuntu 14.04 try downgrading your Linux kernel to Long term supported version
either 3.10 or 3.12
PS: it worked for me and will work for most of the people as 3.12 kernel is stable

 firstly download the 3 deb files which suit ur system architecture
if for 32 bit =>i386
for 64 bit =>amd64
go for files which have generic written
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12.20-trusty/

Go to the downloaded folder

then run this

sudo dpkg -i linux-headers-3.12.20* linux-image-3.12.20* .deb

And then remove the 3.13 default kernel

sudo apt-get remove linux-headers-3.13.0* linux-image-3.13.*
And ur through

If possible change the URI for Kernel updates in Software Center.

Install power monitoring tools like Powertop.

sudo apt-get install powertop

In powertop go to turnables tab and toggle every row from bad to good

also install pm-utils

sudo apt-get install pm-utils

sudo pm-powersave true

this puts ur pc on power save mode