[General Topics] beeshyams:
EDIT: Please jump to post 4 for updated test results . Come back to this post for why this thread

There are umpteen threads on battery saving tips / methods and a few on AMOLED screens and battery savings. So why a new thread, could be the Question

Because

1.Battery saving means are meaningful if backed by numbers, else it’s subjective

2.Tests below were done on N7100, but given the popularity of AMOLED (two dozen and counting per Wikipedia), across cell phones and tabs, this may be interest to battery freaks and hence posting in general section rather than N7100 threads

3.Provide a replicable methodology of testing on your AMOLED device (rooted) both manually and automated. There are threads on XDA as well that suggest testing methodology but have not come up with easy testing methods and automating it unless I missed

I am NOT a qualified guy to understand the technical details of testing screen power nor of the methods/ apps used. There is enough material on the net to show how complex it is and savings using using dark screens vary from 18 to 41 %. IMHO, the jury is out and appears to be taking a long break :o

All I have done is put together various pieces to show a way of testing it and come up with results that are indicative and demonstrate trend lines.

Also the apps chosen for testing is not be misconstrued as canvassing for them.

There may be better ways of doing this test using other apps or better testing ways, which you are welcome to share here.

Test Device Configuration

GT-N7100 (t03g), ROM- Deep Impact (Morph variant) (Kitkat) by [MENTION=5577410]Sammy_052[/MENTION]

Kernel Agni- 3.0.101-India-v4.4.2-OC-INTL-STOCK_HYBRID-KitKat

Apps Used for testing

3C Tool Box Pro: Has a nice feature showing screen consumption in mAh (though on devices like mine which don’t have a current sensor, it is derived from battery drain percentage). Plus, it has the advantage of modules that can be accessed and test automated. Immense thanks to [MENTION=253258]3c[/MENTION] , developer, who helped a ton

Darker : Screen Filter that was thoughtfully provided in the ROM. Free version allows darkening up to 50% as used for test

Stay Alive : To keep the screen alive for two hours (being the test duration), since the maximum screen time out is limited to 10 minutes in KitKat. 3C Toolbox offers a way of choosing apps , which keep screen on, as long as apps are kept in foreground. For some reason, this did not work with Nova Launcher as chosen app, hence the need for a different app. There are many free apps on Play Store with similar functionality and may be used after testing that they do not impact 3C

MacroDroid : To automate the test process. This is by [MENTION=1486719]UndeadCretin[/MENTION] and is a great tool to automate without a steep learning curve. The aim of click starting the test and getting results in mail box has been achieved (barring manual intervention in the first minute of starting the test) . The macro used for this is posted on the app thread. This macro can be easily tweaked and battery bugs can have a field day trying things like Live wall paper, under volting/over volting and altering CPU / GPU frequencies to see impact on power

Broad test Methodology (details later in thread)

Screen power usage was tested in 3 cases. Cell was kept in airplane mode to get cleaner results (optional) and Stay Alive used to keep the screen on for two hours ( targeting to get a drop of 10% battery level) for each test.

Case 1: Bright wall paper

Case 2: Bright wall paper with screen filter

Case 3: Solid black wall paper

Results of Testing ( files attached )

Case 1: Bright wall paper: Screen consumption is 195 mAh

Case 2: Bright wall paper with screen filter: Screen consumption is 189 mAh

Case 3: Solid black wall paper: Screen consumption is 172 mAh

Conclusions

1. Using a solid black wall paper as compared to bright wall paper shows 11 % savings.

2.Using a screen filter on bright wall paper shows very little savings 3% . Was surprised at this result and repeated the test and the results were practically same. This disputes the accepted belief that screen filters save power but is savings as low as this?

Internet reports savings from 18% to 40% by using black screen as compared to 11 % above, am guessing are due to a bunch of reasons, like testing methods, screen size, age of device, device to device variations, ROM, kernel settings, GPU/CPU voltage and frequency to name a few at device level .At next level, is the apps used, usage pattern of phone, algorithms used for dimming the phone and many more.

Testing as above is not real life. To carry out real life testing, ideally one would need to replicate activites for a fixed duration like calling, texting, browsing, watching stored video, on line music / video. I have not come across any app or way of doing this and would be happy to give it a shot, if someone can suggest a simple way

Detailed Test Instructions - To provide consistent testing environment and get clean results

1.Disable scheduled running of apps during the test and Greenify

2.Set the wall paper which you want to test and ensure sufficient battery

3.Run Stay Alive and use the second icon (red one) in the notification bar

4.Run Darker at your preferred settings for tests with screen filter

5.3C settings ( Thanks to [MENTION=253258]3c[/MENTION] )

a)Settings>Recorder>Continuous recording enabled

b)Settings>Recorder>Time frame and Rate- depending on how long (maximum) you want to test and how frequently you want data to be updated, choose appropriate option . I used 12 hours, 10 minutes

c)Settings>Battery>Monitoring> mA retrieval method (if your device is listed choose, For Samsung devices, on enhanced estimated or estimated on the other side is pretty stable and the same for all devices, but often slower to update.

d)Settings>Battery>Monitoring>Estimate, use estimates drain, or if your device has a current sensor and reliably works choose use current sensor

6.Create shortcuts on home screen for battery statistics module of 3C using 3C widget

7.Start the test and go to markers tab and set the marker. You can create markers from the action bar or from history tab long pressing a record. Markers shows average consumption, be it mA or %/h (tap the value to switch). Min/max shows the range for the % or mV. Remember to show full history (not just % changes) by long-pressing the options and tapping “full history”.

8.Time the test and take screen shot of markers results

9.Repeat test for different cases

Looking forward to your views