One of the first things you should do once you install Ubuntu (18.04) on our laptop, is install tlp.

sudo apt install tlp tlp-rdw

Run the following to start the service:

sudo tlp start

To view interesting stats about your laptop you can run the following:

sudo tlp-stat | less

Extra reading:

Most Effective Ways To Reduce Laptop Overheating In Linux.

Is PowerTop / TLP Still Useful To Save Power On Linux Laptops?