There are various ways to change the resolution on Android devices, and I was wondering: Does it have any noticable effect on battery life? And has anybody ever tried doing some proper measurements?
I suspect the reduction in power consumption will not be significant, but you can easily test this yourself using free software like Trepn Profiler. Disclosure: I am part of the team that makes this software. Make sure to follow these best practices, if you want to get the most accurate results.
Another method to measure power consumption is using Monsoon Power Monitor hardware. I forced the screen resolution to 240 dpi using this adb command:
adb shell wm density DPI && adb reboot
Then I measured the power consumption idle and under a load at 240 dpi using the Monsoon Power Monitor. I used the Adreno Test app to load my device. Next I remeasured at the 560 dpi, which is the native resolution of my Nexus 6. At 240 dpi, icons and text appear much smaller on the screen.
Here are the results:
Idle power consumption
240 dpi: 514 mW
560 dpi: 522 mW
Power consumption under load
240 dpi: 3155 mW
560 dpi: 3287 mW
Bottom line: My simple test showed there is almost no benefit to reducing the resolution of your screen via software.