Ubuntu 18.04 – Improve Battery Life

I have almost the same machine (730U3E-S02PL, some slight differences in spec), so I can share my experiences with you. Hopefully it will help you to fix the problems with energy drain.

The main reason for the unnaturally high power consumption is that your discrete graphic card (Radeon) is constantly on. To switch it off, you will have to install the official AMD drivers from:

http://support.amd.com/en-us/download/desktop?os=Linux+x86#amd-catalyst-packages

You can try using beta drivers, but I have found them unstable, so I do not recommend them. Unpack the downloaded file and run amd-driver-installer-XXXXXX.run (with root privileges).

After having installed the drivers, reboot your machine. Run the Catalyst Control Center:

sudo amdcccle

and under the "Graphics switching" or whatever (I've got it in Polish...), choose your Intel card. You will have to reboot your computer again. If you see a window informing you that your computer is running in low graphics mode, do not worry. Click cancel and reboot it again. If unity does not start - power your computer off (by pressing and holding the power button for a few secs) and then on again.

Performing these steps alone improved my battery life from like 2 hours to 4+. It also helps with the fan spinning constantly at high speed.

Next thing you can do is to enable intel_pstate (a new power scaling driver used for modern Intel CPUs):

gksu gedit /etc/default/grub

change the line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_pstate=enable"

Save the file, and run these commands:

sudo update-grub
sudo reboot

Install TLP (tool for setting and managing your power-saving options):

sudo add-apt-repository ppa:linrunner/tlp
sudo apt-get update
sudo apt-get install tlp tlp-rdw

Install thermald (a tool developed by Intel's Open Source Technology Center which monitors and controls the CPU temperature, preventing it from overheating):

sudo apt-get install thermald

To be able to switch the CPU scaling driver easily, you can use the cpufreq indicator. Install it by using this command:

sudo apt-get install indicator-cpufreq

You can find more details here:

1. http://www.webupd8.org/2014/04/prevent-your-laptop-from-overheating.html
2. http://linrunner.de/en/tlp/docs/tlp-configuration.html

You have installed TLP to extend the battery life on your laptop, but are still getting poor battery life. When you look at the output of tlp -stat output you found the error message x86_energy_perf_policy: program for your kernel not installed.

When you attempt to install the energy performance policy by sudo apt-get install linux-tools-generic the install appears to work but does not have any effect.

I have looked at the code for x86_energy_perf_policy and I could see no issues with it. It does not appear to be kernel specific so it looks like x86_energy_perf_policy which is part of linux-tools-common is not linked into the kernel properly.

This will have a big effect on battery life for laptops with Intel CPUs since the default policy is to maximise performance at the expense of energy expenditure (and hence battery life).

I may be wrong and x86_energy_perf_policy could be depreciated and TLP has yet to catch up but this looks like a serious kernel bug. I could attempt to patch your kernel to resolve this, but this issue will effect this and subsequent versions of the Linux kernel until it is resolved so I suggest you raise a bug by entering ubuntu-bug at a terminal. Feel free to paste parts of this answer into your bug report if this helps.