I use Ubuntu 16.10 and GeForce GT 520M. Nvidia-367 driver installed. When I take a look Power Mizer section on Nvidia X Server Settings, Power Source shows always AC even if I unplug the AC.
It looked to me this situation cause a negative effect on battery life.
Rather than this problem, I will be appreciated if you tell me if there is any setting for maximum power save on battery power. I only see Prefer Maximum Performance and Adaptive.