[Q] Rooting - effect on battery life

Randy Lahey · Apr 9, 2012

I'm trying to decide whether to root my NST or just leave it as is. I would certainly like to have the extra functionality, but not at a large cost to the battery life. After all, I did buy it as an e-reader first and foremost, so battery life is a very important factor.

I've searched the thread a bit and have seen some people complain a great deal about battery performance after rooting, however perhaps this is down to programs they decide to run, rather than the rooting process itself with the latest touchnooter.

So, could one of you veterans please comment on your experience with battery life after rooting?

Cheers,

R

brendan10211 · Apr 9, 2012

From my experience, most battery is wasted when refreshing the screen. When you root, most of the time your goal is to use some random android app. This means you are going to be refreshing the screen often, which uses battery.

Someone else tell me if I am wrong, thanks

fufutos · Apr 9, 2012

I don't think that root itself has any impact on battery life, but as you can do more with rooted nook, you consume more. Last week I've used mine almost 100% as a reader and battery is at 50%... and I read much more than 1 hour a day (that's the presumption for "2 months battery life" from B&N

)

klausef · Apr 10, 2012

I've accidentally voted 'significant decrease' whereas in reality I have seen no change. An issue I've run into is that I have 'Keep Screen On' checked in EBookDroid so the page doesn't go away, but then when I'm done reading I forget to hit the power button to sleep it. This has drained the battery on me more than once.

Incidentally, it would be superfly if someone hacked together a script that copied the framebuffer to a file in the screensaver directory so when it went into sleep mode it would keep displaying the page while not wasting batteries.

I might hash that up when I have time.

ApokrifX · Apr 10, 2012

klausef said:
I've accidentally voted 'significant decrease' whereas in reality I have seen no change. An issue I've run into is that I have 'Keep Screen On' checked in EBookDroid so the page doesn't go away, but then when I'm done reading I forget to hit the power button to sleep it. This has drained the battery on me more than once.

Incidentally, it would be superfly if someone hacked together a script that copied the framebuffer to a file in the screensaver directory so when it went into sleep mode it would keep displaying the page while not wasting batteries.

I might hash that up when I have time.

There is system/bin/screenshot

Code:

screenshot /media/001.png

Don’t know how to hook it up to sleep event, hopefully should be very difficult.
Dirty hack – delete all screen saver images, than use screenshot, so it’ll be the only one to pick...

Renate · Apr 10, 2012

ApokrifX said:
There is system/bin/screenshot

Then yours must work better than mine.
They completely screwed up the bitmapping from 565.
Take a shot, it's all blue.

Details here: http://nookdevs.com/Nook_Simple_Touch_screen_capture

Googie2149 · Apr 10, 2012

Renate NST said:
Then yours must work better than mine.
They completely screwed up the bitmapping from 565.
Take a shot, it's all blue.

Details here: http://nookdevs.com/Nook_Simple_Touch_screen_capture

Same thing was happening to mine. More of a cyan/teal, though.

klausef · Apr 10, 2012

we don't even need it to hook to the sleep event; i was considering just having a service that waits for two minutes of inactivity, clears out the screensaver directory (as mentioned) and then writes a screencap to it.

ApokrifX · Apr 11, 2012

Renate NST said:
Then yours must work better than mine.
They completely screwed up the bitmapping from 565.
Take a shot, it's all blue.

Details here: http://nookdevs.com/Nook_Simple_Touch_screen_capture

I've never tried it, actually...

Renate · Apr 11, 2012

I've seen something happen randomly, I addressed it in another post:
http://xdaforums.com/showpost.php?p=24232518&postcount=9

On occasion the touch screen sensors do not turn off when the Nook goes to sleep.
Whether this indicates that nothing has gone to sleep or just that the sensor has not gone to sleep is unclear.
Still, you can lose about 4% of a charge per hour overnight.

If you run into this, there is something that you can try:

Code:

adb pull /data/data/com.android.providers.settings/databases/settings.db settings.db

sqlite3 settings.db
sqlite> update system set value=0 where name='stay_on_while_plugged_in';
sqlite> .q

adb push settings.db /data/data/com.android.providers.settings/databases/settings.db

3 is the normal value, telling the Nook to stay on always with USB or charger power.
Unfortunately, once a charger/USB is plugged in it gets its state all confused.
Even with this set to 0 the screen sensors stay active while plugged in.

brendan10211 · Apr 11, 2012

Or just turn it off

Randy Lahey · Apr 22, 2012

Thanks to all those who replied.

So, basically what you're saying is that if I were to root my NST, but continue to just use the nook software, I will basically get the exact same battery life? And that battery life is only affected by other programs that I may install?

So there is nothing installed standard on the nooter rooting software that causes additional battery drain?

bobstro · Apr 22, 2012

Randy Lahey said:
[...] So, basically what you're saying is that if I were to root my NST, but continue to just use the nook software, I will basically get the exact same battery life?

Exact is impossible to say, unless you're doing some sort of structured testing. What I can tell you based on my experience is that, if you're careful with what runs in the background, you can see battery life on a rooted NST on par with what you'd see unrooted.

And that battery life is only affected by other programs that I may install?

Only? No, not exactly. Whether you leave wifi on or off will make a big difference in battery life, whether rooted or not. Thus the statement that "battery life is only affected by other programs" is not true. Other programs may affect battery life, but may not be the sole consumer of battery.

In my ad-hoc testing, I saw battery drop roughly 1% per hour with wifi on. With wifi off, that drops to something less than 1% per 6 hours.

So there is nothing installed standard on the nooter rooting software that causes additional battery drain?

You're asking questions like a lawyer! I'm not comfortable saying that "there is nothing installed standard on the nooter rooting software", because the Android Market does check in the background for updates, so will consume some battery. Gmail is also installed, and can be set to do background updates.

You also haven't specified a rooting method. Some variants have loaded all sorts of additional software. I can only say that the software loaded by TouchNooter seems to have minimal impact.

Controlling when wifi is enabled has made the biggest impact on battery life in my experience. I'm using Tasker to control when wifi turns on and off, limiting it to a small handful of foreground apps. I disable any background synchronization I can.

The other question nobody can answer for you is how you'll use the device. Screen activity does impact battery life. If you're just reading, there's less of an impact than if you're playing Angry Birds.

genoxygen · Apr 22, 2012

SetCPU app

I heard that configuring the CPU may save battery life. I have installed the app SetCPU on my NOOK. Does anybody else have it? How could I configure it to save battery life?

http://urlin.it/2e6b2

bobstro · Apr 23, 2012

genoxygen said:
I heard that configuring the CPU may save battery life. I have installed the app SetCPU on my NOOK. Does anybody else have it? How could I configure it to save battery life?

http://urlin.it/2e6b2

There's a bit under the ManualNooter thread about underclocking to improve battery life. I haven't read about it myself, and have only read comments that the improvement is marginal.

Randy Lahey · Apr 23, 2012

bobstro said:
You're asking questions like a lawyer! I'm not comfortable saying that "there is nothing installed standard on the nooter rooting software", because the Android Market does check in the background for updates, so will consume some battery. Gmail is also installed, and can be set to do background updates.

Thanks Bobstro, appreciate your response. And anything you say can and will be used against you in a court of law. Nah, I'm not a lawyer....but an accountant...just as bad.

It sounds like the effect will be minimal after rooting the nook unless I install something more intensive.

That being said, can always just restore with the old backed up image if I'm not happy, so the downside seams minimal.

bobstro · Apr 23, 2012

Randy Lahey said:
[...] That being said, can always just restore with the old backed up image if I'm not happy, so the downside seams minimal.

With the usual caveat that YMMV, and a warning to back up the device before you start (the NST can't always be completely restored as easily as other B&N devices), I think you're all set!

Just sign this release form...

fufutos · Apr 25, 2012

Last report: mine... well I don't remember when was the last time I've charge it - but it was before Orthodox Easter festivities (i.e. 11 April), and is still at more than 60%, reading at least 2 hours a day!

leoparis · Apr 25, 2012

i had a 4% drain overnight on standby. i don't have that many applications installed (nothing I can think of that would lead to high battery drain at least). i have to look into it but i seem to have "excessive" battery drain after rooting.

bobstro · Apr 26, 2012

leoparis said:
i had a 4% drain overnight on standby. i don't have that many applications installed (nothing I can think of that would lead to high battery drain at least). i have to look into it but i seem to have "excessive" battery drain after rooting.

Is wifi on or off? Anything that wakes the device up will cause an increase.

[Q] Rooting - effect on battery life

Battery life after rooting

No change in battery life

Small decrease in battery life

Significant decrease in battery life

Increase in battery life

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