I also noticed reduced battery life from like 5hrs to 2hrs max. Did some research and installed TLP. That kind of helped but not much. Some people advised to downgrade to kernel from 14.10 but I didn't want to do it.
Instead, I preferred to update to kernel 4. Installing it manually didn't do it so I did some research and found the script that works for whatever version you've got. I downloaded it from https://github.com/GM-Script-Writer-62850/Ubuntu-Mainline-Kernel-Updater and installed it. Than on next reboot info of new available kernel appeared so I run it:
sudo /tmp/kernel-update
Reboot and voila. back to 5-6hrs battery life with TLP enabled and nvidia drivers using intel integrated graphics card (power saving mode). happy days
oh btw my specs:
- laptop dell 7537
- Intel i7-4500U CPU @ 1.80GHz
- 8GB ram
- Ubuntu 15.04
- kernel 4.0.0-040000-generic
- graphics card nvidia gforce 750m 2gb dedicated ram
systemd
so insystemd
command to list running services issystemctl status