Database Users

Battery life problem - solution

I was pondering possible reasons for the battery life problem that many of us are well aware of. Some peoples batterys will last a good day or two and then theres people like me who charge my phone in the morning and when i get home in the afternoon just to keep it alive and this is compared with people using the same rom. So i thought maybe there could be something to do with what the battery level is when the phone is rooted or a new rom flashed, and this process may reduce the battery cycle to a specific point. E.g. if i 1st root and load my new rom on my phone at 50%, when booted it could show 100% but its actually 50% than it should be. i have not tested this but im just putting it forward as an idea. if anyone does have the time to unroot, charge to 100% and then reroot their phone + custom rom and test the battery life could they please post their results here. No harm in trying ...
EDIT:It seems we have found a solution or alteast a way to greatly improve battery life by putting my random idea and the information from maxisma togethere.. here are the following steps:
1. When the battery is low e.g. 10% boot into recovery mode and wipe->battery data
2. Reboot and then drain the battery or let it die (turn on mobile network add the 'sync now' widget and keep syncing with the music on loud - works pretty fast)
3. Leaving the phone dead put it on charge and let it charge fully till the led indicates green (may take longer than normal)
4. UNPLUG!! the charger then boot the phone up and your battery life should be much better
TIP!! Remeber when changing and flashing new roms to unplug the phone from charge after you boot!
Hope this works for you all PM me for results (i went from 5-10% loss an hour to what is now about 1-2% max )

Nice idea but almost certain your wrong
Edit: turns out that you shouldn't boot your phone while charging after all

I've think it's more likely to do with how I charge my phone. If I charge the phone on my PC then the battery lasts me a day. On Sunday night I charged it with a mains charger, and a day and a half later I still have 40% left. That's with constant WiFi, Talk, calls and text messages.
Sometimes I'll do the same things mentioned above and the battery will be about 20% by the time I'm going to bed.
I could be very wrong, I'm no battery expert!

There shouldn't be any difference between PC charging and mains charging. The mains charger would utilise a transformer to give the same oomph as a PC gives...if not it'd fry the battery whilst charging.
Funnily enough, mains AC - DC transforms are a little choppy, although at such a low current it should be entirely negligible, but your PC's power supply should give a cleaner power output than the mains. Are you sure it isn't just a placebo, I still like to think charging my PSP via the mains rather than USB will do it quicker and last longer, since its dedicated

TheAshMan said:
I've think it's more likely to do with how I charge my phone. If I charge the phone on my PC then the battery lasts me a day. On Sunday night I charged it with a mains charger, and a day and a half later I still have 40% left. That's with constant WiFi, Talk, calls and text messages.
Sometimes I'll do the same things mentioned above and the battery will be about 20% by the time I'm going to bed.
I could be very wrong, I'm no battery expert!
Click to expand...
Click to collapse
I've heard this theory before. I can't even begin to fathom how this could be possible. I hereby dismiss it as 'rubbish'.
Seriously though, I think it's far more likely to be related to the apps/widgets people are using after flashing the rom. The only thing that differs drastically from build to build is the different apps that people install.
Might be worth those with very crap battery lives sending me an hours worth of logcat. I can do an hours worth of logcat for myself (I never have battery issues), and compare the results.

He's partly right.
Android has a bug that when it's plugged into a charger while booting up, it'll report a higher battery status than it actually is.
This is preventing the phone from charging the battery completely.
So, a recommendation for you: Always unplug your phone from the charger before powering it up.

Attempt
Since my last post ive drained my battery out. Kept the phone off and charged it fully. It did take longer than normal which could be a good thing. Ive booted it up about 15 mins ago and il post later/tomorrow about how the battery performs now.

WOOO
I maybe jumping the gun a bit here but my phone says an up time of 1hour 27 mins. and normally its about an hour to about 5-10% of battery life and im sorry to say... im still on 100% WOO . I will still report how this lasts through to tomorrow, however i think theres enough evidence to suggest that the method stated earlier seems to fix what seemed to be a 'shortend battery cycle'. Anyone else with a short battery life i advise you to do the same asi have and please feedback to me with any results.. hope this has been helpful
EDIT: Its been two hours now and still 100% woooo

I got escited too bratfink when I had 100% battery for ages while it was in sleep, then I dl'd a few progs from market and whoosh my battery started disappearing faster than expected. Try downloading a few things and you'll see your battry disappearing quicktime.
minfree or ramzswap off could be causing the issue.
I remember before I put that tweak on my phone (when it first came out), my battery life was amazing.
After I put the values in for init.d as from the forum page below:
http://forum.xda-developers.com/showthread.php?t=622666&page=6
the battery life started disappearing like mad! and this was on a modaco rom!
I think now that all the new 2.1 roms are including this minfree tweak it is causing this battery issue to be carried over. All attempts to reduce battery drain are not having as much effect as they could because of this.
I would like to try one of these new roms without the tweak but I do not have the knowhow to stop it. i.e. put the original init.d (or equivalent) for the the roms in place.
You might argue that the memory clearing has nothing to do with the battey drain, but what i saw was that it did on a modaco rom. I don't know whether it is the switching of ramzswap or the minfree settings ( i have a feeling it is both.
Can a chef cook one of their roms without the tweak and keep the original settings?

adb remount
adb shell rm /system/etc/init.d/02memkill
then reboot.

kendong2 said:
adb remount
adb shell rm /system/etc/init.d/02memkill
then reboot.
Click to expand...
Click to collapse
I'm on the BeHero v1.3.2,m will that command put my phone memory settings back to what they would normally be without the taskkiller?
If so can I just remove that file with OI file explorer as atm my laptop usb aint working (can't connect to phone properly, can only charge)

If you use Bluetooth, GPS*, or plug/unplug usb, CPU lock at 528Mhz and battery drain. This happend in all eris/roms.
I can see with Battery Graph while I sleep the battery is full, but no reason (only unlock to check time, kill alarms, read mail,...) the battery drains constantly. (no tweeter, no facebook, no GPS, no BT,..),
This kernel sucks. It's very buggy but is what is

kendong2 said:
adb remount
adb shell rm /system/etc/init.d/02memkill
then reboot.
Click to expand...
Click to collapse
It's OK managed to fix the usb on my laptop.

I am currently performing the third step...i really hope this works cuz I am getting really really horrible battery life right now...I get only about 8 hours with ocassional use...like listening to music, browsing, taking pictures, sms.
thanks for posting this thread.
Ill post the results tomorrow ( hopefully positive)

I noticed that using the overclock widget (even with the lower clock option when screen is off) also eats some battery, it definitely reduced my usage time on Android 1.5.
Could someone confirm?

I dont know what it is and why people have this bad battery drain.
I have the VillainRom 3.4 installed. Totally NO drain. I turned on Bluetooth and called several times. Battery drain is 8% in 12 hours .
I did not install any widgets. Pure standard custom ROM with newest radio.

Leeejohn said:
I dont know what it is and why people have this bad battery drain.
I have the VillainRom 3.4 installed. Totally NO drain. I turned on Bluetooth and called several times. Battery drain is 8% in 12 hours .
I did not install any widgets. Pure standard custom ROM with newest radio.
Click to expand...
Click to collapse
exactly my view.

I'm using HeroDroid and i had really bad battery drain problem. I'm a sort of heavy user and with bluetooth & gps permantly on, my phone had drained out by lunch time. After doing some tests, i have found that my problem was related to GPS. If i boot my phone with GPS off and left it at off, i get the same battery level usage as my original cupcake 1.5 ROM. Perharps you guys can try it and post your results.

rubik said:
I'm using HeroDroid and i had really bad battery drain problem. I'm a sort of heavy user and with bluetooth & gps permantly on, my phone had drained out by lunch time. After doing some tests, i have found that my problem was related to GPS. If i boot my phone with GPS off and left it at off, i get the same battery level usage as my original cupcake 1.5 ROM. Perharps you guys can try it and post your results.
Click to expand...
Click to collapse
I found that to help as well. In the last 3h10m it only went down by 4%. That's definitely a lot better than what I was getting before and with the previous ROM. I am using the new Autokiller and Overclock widget if that helps any and booted up with my GPS off and followed the steps mentioned in the first post.

hmm if its the case that the phone is "capping" the maximum amount of charge the phone can have then it should take longer to charge also
my battery life i kinda okay, lasts 10-12 hours with intermediate use, using battey graph app it took me 70 mins to charge from 40% to 100%
ill let it drain out tonight and see how long it takes for a full charge
it would be good if we could compare results with people with and without battery problems

Possible solution to the battery drain prob (WiFi only)

This is for the WiFi only A500.
Just noticed that if you install the power control widget (the free one) from the market, and configure one of the buttons as a 2G/3G switch, on pressing it you get to a menu that's not available through Settings (is missing from the WiFi and connections menu). There you have the option to unselect the Data enabled checkbox. I'm not sure yet, but I seem to be getting better battery life (although Cell standby will still show up in Battery use; still, that value is a percent of the total drainage, which seems to be smaller).
Please try it out and let the others know of your results.

Noted Before - Did Not Seem To Resolve Much
Actually many widgets have the property of opening up "hidden" settings, e.g.,
docfreed said:
Wow! I just went into my Beautiful Weather settings and under the "Advanced Panel" you can specify an action for clicking on the time (or weather). When this is done, it provides a large list of action - this list, to the best of my knowledge, doesn't show up anywhere.
Anyway, Mobile Data was checked (yes or on) so I cleared the list (resulting in mobile data being UNCHECKED) and rebooted. Mobile data remained unchecked so I'll watch for a while and report results later.
Click to expand...
Click to collapse

Could be placebo, I agree. Well, no harm done in any way

sure fire fix
Although it has been said that by renaming the phone.apk and telephony.apk you may risk bricking the device during a factory reset, I have renamed both and have seen an incredible increase in battery life.
Currently at six and a half hours of moderate use for music and web with some standby time and have 88% battery left. No cell standby being shown in battery stats either.
Reboots are fine, just don't factory reset without renaming the apk files back.

Installed Free Power Widget from the Market, says its installed but doesnt show in my widget list, strange.

Cell standby is simply terminology for when the tablet is asleep meaning screen off. So I wouldn't start changing it. In all likelihood you have an application that tries to access those two apps and when it doesn't find them it can't run its background process. I bet finding the culprit app would equally fix battery life.
cbotd said:
Although it has been said that by renaming the phone.apk and telephony.apk you may risk bricking the device during a factory reset, I have renamed both and have seen an incredible increase in battery life.
Currently at six and a half hours of moderate use for music and web with some standby time and have 88% battery left. No cell standby being shown in battery stats either.
Reboots are fine, just don't factory reset without renaming the apk files back.
Click to expand...
Click to collapse
Sent from my A500 using Tapatalk

peejayw said:
Installed Free Power Widget from the Market, says its installed but doesnt show in my widget list, strange.
Click to expand...
Click to collapse
I had the same, switch off and reboot made it appear in the list.
In much the same way photos I copied from a portable hdd onto the micro SD didn't show until I had powered off and on again.

Thanks, that did the trick.

@Canadoc: "Cell standby is simply terminology for when the tablet is asleep meaning screen off. So I wouldn't start changing it."
I do not believe this is correct. If this were true, removing Phone.apk and Telephony.apk would not affect battery usage, because the tablet would still use just as much power when the screen is off and it would still list "Cell standby" on the battery usage screen. In actuality, removing these two apps causes Cell Standby to disappear from the battery usage list and decreases actual battery usage. Plus, my "Cell Standby" % on the battery usage screen is highest when I have my tablet awake all day, and lowest on days when I let it go to sleep much of the time. So it must be doing something else in Cell Standby that uses power, probably trying to contact cell towers (in vain) even though it is a wi-fi only device.
A few minutes of Googling reveals that many Android wi-fi only models have the same problem (they try to access cell service even though they have no cell capability) and removing Phone.apk and TelephonyProvider.apk seems to fix the problem for everyone who's tried it. I have rooted my own A500 and removed them and it has given it an extra hour of battery time per full charge. YMMV, and it may someday brick when there's an update or something, but for now it works great. Cell standby was definitely doing something that it is now no longer doing.

I'm not 100% sure if android respects them(more experience on Linux than Android), but couldn't we just remove the exec flag off of the apk and not worry about bricking?
Or possibly set it's owner to system and deny rights to everyone but owner? Would that still allow updates?

I thought anything PRIOR to Honeycomb was made for phone ? ( froyo, gingerbread ...etc )
That info was actually made in press by Google !
So in essence, HC is for tablet ONLY ! why are we still seeing cell standby and phone apk ?
even if you argue because some tablets are 3G models ... 3G is about DATA ... not making a phone call !!! ( imagine bringing a 10" device up to the side of your ears )
there are some 7" tablets that are GSM capable... so, they CAN make GSM calls, and they DON'T use Honeycomb either.
anyone care to enlighten me why here we are with Honeycomb and still have the cellstandby and phone APK ??

UnicornKaz said:
anyone care to enlighten me why here we are with Honeycomb and still have the cellstandby and phone APK ??
Click to expand...
Click to collapse
Because Google are a bloody idiots?

Because hc was built on gingerbread. It wasn't built from nothing.
Sent from my Desire HD using Tapatalk

[Q] Acer A500 Wifi, Extend Battery Life

Hello.
I did some google searches and i've found a thread where someone claim that:
* locating the directory /system/app -> PHONE.APK and TELEPHONY.APK
* removing or renaming this files, for example to PHONE.OLD and TELEPHONY.OLD
is the trick to extend the battery life, you'll earn a few hours. True or, ... a metropolitan legend ?

Don't advise it ....
matthew79 said:
Hello.
I did some google searches and i've found a thread where someone claim that:
* locating the directory /system/app -> PHONE.APK and TELEPHONY.APK
* removing or renaming this files, for example to PHONE.OLD and TELEPHONY.OLD
is the trick to extend the battery life, you'll earn a few hours. True or, ... a metropolitan legend ?
Click to expand...
Click to collapse
Well, lots of people are doing it, but it will apparently cause problems with updates, and may even brick your tablet if you update with those files renamed. Instead, just set your tablet to 'airplane mode' and turn on Wifi. My tab is getting 12 to 14 hours almost continuous use this way.
My advice is NOT to do it. We will be getting the Honeycomb 3.1 update in June, and it is supposed to address this issue.
Sent from my Iconia Tab A500
everythingiconia.blogspot.com

Thanks for your explanation

I just turn on airplane mode. i have to turn on wifi sometimes, but battery usage for cell is stopped.

This seems to work OK!! Thanks for the suggestion!

sometimes it can be so easy and even works without root

phone.ds said:
I just turn on airplane mode. i have to turn on wifi sometimes, but battery usage for cell is stopped.
Click to expand...
Click to collapse
I have been tried this from yesterday but no effect for me. Cell standby process eats 27% of battery consumption.

Can we make this subject a sticky?

Fantastic tip and working great for me. If you don't mind I would like to share this on another Android forum.

phone.ds said:
I just turn on airplane mode. i have to turn on wifi sometimes, but battery usage for cell is stopped.
Click to expand...
Click to collapse
Turning on Airplane mode did not work for me.
I am always in Airplane mode and if battery usage is accurate then cell standby is still the second biggest drain on battery (next to display).
This issue and the amount of bloatware are really my only two gripes with this tablet.

turning on airplane mode will not work. Rename those two files and just name them back when restoring or updating your tablet. Just don't forget or you'll brick it. My battery life is awesome when it sucked before

Turning on Airplane mode didn't seem to work for me either. The percentages are still much the same.

require to root the device ?

apple_hd said:
require to root the device ?
Click to expand...
Click to collapse
Yes, you need to root your device. Use Gingerbreak and then a good file manager, maybe Root Explorer (market.android.com/details?id=com.speedsoftware.rootexplorer&feature=search_result). It's not free but it's wonderful.

Get the "Acer Iconia Phone Disabler" app. It gives you easy, push-button support of this, and works flawlessly. If you decide to update, you just use the app again to enable the telephony services.
Darned near fool-proof.

jimbobtexas said:
Get the "Acer Iconia Phone Disabler" app. It gives you easy, push-button support of this, and works flawlessly. If you decide to update, you just use the app again to enable the telephony services.
Darned near fool-proof.
Click to expand...
Click to collapse
I don't have anything against paid apps. In fact my Iconia has got a lot of paid apps but this app seems useless. It does the same thing explained in this thread with 1 click. By the way, if you suggest paid apps, it's always a good thing to insert a reminder....

Why the hell this tablet have cell radio if we can't use it ?

Airplane mode
I agree that the battery use report still shows that cell standby is eating up the battery, up to 15% on my A500, however that does not change the fact that my battery life has increased to 12 to 14 hours on an average day of use.
Why don't you turn on airplane mode and turn on WiFi and use it that way for a day or two and see what happens? Maybe it doesn't work for you, but it is working for me and others.
You can't always believe what a report tells you, but you can usually believe what you observe for yourself.
My settings app also tells me my 16 gig external SD card is only 14 gig, but I know better than that. I can stick it in my laptop and it reports 15.something gig. Maybe the OS just thinks it is polling for service while in airplane mode, but in actuality it isn't.
And to repeat what someone else asked, why the heck does a WiFi only tablet have a cell radio in it anyway? Even if is part of the main board, it should have been diabled.

battery drain
kwparker80 said:
I agree that the battery use report still shows that cell standby is eating up the battery, up to 15% on my A500, however that does not change the fact that my battery life has increased to 12 to 14 hours on an average day of use.
Why don't you turn on airplane mode and turn on WiFi and use it that way for a day or two and see what happens? Maybe it doesn't work for you, but it is working for me and others.
You can't always believe what a report tells you, but you can usually believe what you observe for yourself.
My settings app also tells me my 16 gig external SD card is only 14 gig, but I know better than that. I can stick it in my laptop and it reports 15.something gig. Maybe the OS just thinks it is polling for service while in airplane mode, but in actuality it isn't.
And to repeat what someone else asked, why the heck does a WiFi only tablet have a cell radio in it anyway? Even if is part of the main board, it should have been diabled.
Click to expand...
Click to collapse
have you by chance run a battery monitor such as "battery monitor widget" that gives the mA rating of the power drain? Mine is still very high (400-1200 mA) when doing your solution. I'd be interested to know your drain b/c based on the projections I'd only have between 4 and 6 hours use, not the 12-14 you get. Thanks

tower107 said:
have you by chance run a battery monitor such as "battery monitor widget" that gives the mA rating of the power drain? Mine is still very high (400-1200 mA) when doing your solution. I'd be interested to know your drain b/c based on the projections I'd only have between 4 and 6 hours use, not the 12-14 you get. Thanks
Click to expand...
Click to collapse
There's absolutely no way to get 12-14 hours of continuous use out of this tab. I think many people reporting otherwise are counting sleep time as well.

Question about sleep in Iconia Tab

Hello all,
Trying to find some info about some behaviour my Iconia has.
I love my device. Way more capable than my wife's Ipad and all that. There's only one thing that irks me: battery drain while the device is idle.
I also have a B&N Nook 1st gen (for books) and an EVO 4G. I leave and use the Iconia mostly at home, close to the WiFi. I'll take it out for long trips and such, but it stays close. I have it set up so that the WiFi antenna turns off when the screen does. Low brightness on the screen, will only charge the battery when it's low enough to charge, etc. It stills drains close to 6-8% if I leave it alone a couple of hours.
Earlier today I rooted the device and use Bloatware Freeze to freeze some stuff. Eventually I'll get rid of some of the gunk the tablet has installed. I want to figure out how to shorten that gap. It doesn't make a whole lot of sense to me that the tablet left alone consumes 8% of battery charge! I mean, if nothing can be done then so be it, I'll learn to live with it.
For my money I would bet that there is something hidden in the Iconia's OS build that thinks it is a 3G/4G device. Now, I'm wondering what would happen if I were to take the next (logical) step and put another ROM in it. Would this make a difference? If I can make the battery drain stop at 5% or less, that would make this perfect.
Thx!

citizenklaw said:
Hello all,
Trying to find some info about some behaviour my Iconia has.
I love my device. Way more capable than my wife's Ipad and all that. There's only one thing that irks me: battery drain while the device is idle.
I also have a B&N Nook 1st gen (for books) and an EVO 4G. I leave and use the Iconia mostly at home, close to the WiFi. I'll take it out for long trips and such, but it stays close. I have it set up so that the WiFi antenna turns off when the screen does. Low brightness on the screen, will only charge the battery when it's low enough to charge, etc. It stills drains close to 6-8% if I leave it alone a couple of hours.
Earlier today I rooted the device and use Bloatware Freeze to freeze some stuff. Eventually I'll get rid of some of the gunk the tablet has installed. I want to figure out how to shorten that gap. It doesn't make a whole lot of sense to me that the tablet left alone consumes 8% of battery charge! I mean, if nothing can be done then so be it, I'll learn to live with it.
For my money I would bet that there is something hidden in the Iconia's OS build that thinks it is a 3G/4G device. Now, I'm wondering what would happen if I were to take the next (logical) step and put another ROM in it. Would this make a difference? If I can make the battery drain stop at 5% or less, that would make this perfect.
Thx!
Click to expand...
Click to collapse
I leave my device with airplane mode checked, and then re-check wifi (as airplane mode will initially turn off your wifi). I get no strange programs showing up in battery usage now.

Will certainly try...
I'll try this next time I head out. Will leave her in Airplane Mode and will check the battery level when I come back.
I did disable the GPS and all location settings. I do not need it to know where I am, since I have the EVO for that.

citizenklaw said:
I'll try this next time I head out. Will leave her in Airplane Mode and will check the battery level when I come back.
I did disable the GPS and all location settings. I do not need it to know where I am, since I have the EVO for that.
Click to expand...
Click to collapse
Right on, let us know if that helps ya out

Well I'm glad I came across this. I didn't even think about leaving the GPS on and consuming battery. Also, where did you adjust for your wifi to turn off when the screen goes off?
EDIT: Nevermind, I found it.

I am developing an app that uses bluetooth and I noticed that if I leave bt on my tab will go dead in 2 days, if I turn it off it can stay idle for several days before needing a charge. I leave the wifi on all the time.

citizenklaw said:
Hello all,
Trying to find some info about some behaviour my Iconia has.
I love my device. Way more capable than my wife's Ipad and all that. There's only one thing that irks me: battery drain while the device is idle.
I also have a B&N Nook 1st gen (for books) and an EVO 4G. I leave and use the Iconia mostly at home, close to the WiFi. I'll take it out for long trips and such, but it stays close. I have it set up so that the WiFi antenna turns off when the screen does. Low brightness on the screen, will only charge the battery when it's low enough to charge, etc. It stills drains close to 6-8% if I leave it alone a couple of hours.
Earlier today I rooted the device and use Bloatware Freeze to freeze some stuff. Eventually I'll get rid of some of the gunk the tablet has installed. I want to figure out how to shorten that gap. It doesn't make a whole lot of sense to me that the tablet left alone consumes 8% of battery charge! I mean, if nothing can be done then so be it, I'll learn to live with it.
For my money I would bet that there is something hidden in the Iconia's OS build that thinks it is a 3G/4G device. Now, I'm wondering what would happen if I were to take the next (logical) step and put another ROM in it. Would this make a difference? If I can make the battery drain stop at 5% or less, that would make this perfect.
Thx!
Click to expand...
Click to collapse
Wow I don't even have 8% drain with Wifi on all the time. There maybe something else in the mix. Most of my drain is the screen as I set it to auto and in my home it ramps up brightness most of the time. Is it possible you have a rogue app? Have you tested the tablet 'fresh', ie: after a factory reset with 1 google profile set up?

Neoprimal said:
Wow I don't even have 8% drain with Wifi on all the time. There maybe something else in the mix. Most of my drain is the screen as I set it to auto and in my home it ramps up brightness most of the time. Is it possible you have a rogue app? Have you tested the tablet 'fresh', ie: after a factory reset with 1 google profile set up?
Click to expand...
Click to collapse
This is interesting, on 3.01 & 3.1 I've had zero drain with screen off w/up to 16 hrs. Settings : Wi-Fi disconnect policy never when plugged in, location & security use wireless networks on & gps on. Airplane mode , always off. I can't understand why you folks are having these problems. Hope we find out. Oh & by the way that's not charging.
Forgot to mention I use Juice Defender.

Update
Well, after much tweaking I think I'm somewhere where I feel comfortable. As a disclaimer I don't take the Iconia with me on my daily commute. Again I take my EVO and my Nook with me. The tablet spends the entire time I'm out in the office at home, unused.
I disabled all screen animations and I'm using the tablet on the lowest brightness setting.
I disabled the GPS and all location-related settings.
I rooted the tablet and am using Bloat Freeze to freeze/disable some of the Acer 'junk'.
I put the table in Airplane mode before heading out.
Last night when I went to bed I didn't use it (I was reading a very good book and I did not use the tablet to watch any of my shows). So I put it in airplane mode after I played with the new Google Music app (Impressive!). I went to bed around 11:00 and woke up at 5:00. In this span of time, battery went down by 1%.
Used it this morning to tweet, check a couple of websites, email. Was @ 71% at 7:00AM. Came back close to 7:00PM. Battery was at 67%. Right now (8:50 EDT) it's at 1d 19h 55m on battery @ 59% charge. Heavy usage of TweetCaster, TuneIn Radio, Browser, Market, &c.
Mind you, it was not used for close to 8-9 hours or more. If I were to take it with me the consumption would be more, but then I would probably use Airplane mode when it was not in use. Besides, I can't use it at work b/c the wireless is not compatible.
I'll keep doing some research, but I'm comfortable. I accept the fact that it will drain regardless, since the OS is up. The previous consumption was too much, and I think I can live within the 2% - 4% consumption rate. If it can go down to 1%, though, that would be even better.
Any other ideas welcome.

beautiful Widgets comes with a widget to disable/enable wifi like we're all used to on our phones.
I loaded prime 9.3 today because I wanted to try a 3.2 rom (for GPS and sd-card reasons). On that rom I noticed the 3g settings were visible until I added the line "ro.carrier=wifi-only" to build prop. I was able to see cell standby show up in batt usage.
Not sure if you guys knew it or not but under battery usage you can click on the graph to see a graphical depiction of what hardware used the battery when. If GPS was active when it shouldn't have been you'll see it there.

Interesting...
Are you suggesting that the 3g apk is active on the 3.1 image? I posted this question to a developer in Market that has an app that kills this on the Iconia. Maybe that's the other 2% - 4% I can kill.

Prime is a 3.2 rom. You could try adding that line and rebooting though.

To the stock 3.1 image? Interesting. Any instructions?

You'll need an app like root explorer that will let you mount the /system partition as read/writeable. In the /system directory there will be a build.prop file that you can open with a text editor (root explorer has this feature built in). You'll see many "ro.xxx" lines. At the end of the first group you'll just need to add the line "ro.carrier=wifi-only" without the quotes. Save and exit the file. Reboot tablet. On reboot, it will read the values in build.prop.
On the prime 3.2 rom, the settings for mobile networks are visible without that line added to build prop. I was actually seeing cell standby in the battery usage list. I never saw that on the stock rom. I use a toggle button for the wifi to quickly turn it on/off from the home screen and that keeps wifi from using any battery while sleeping..
I really doubt that GPS is the culprit in your case. Did you click on the battery usage graph to see what hardware was using the battery during the period of sleep?

Also remember
The % charge that the system reports is not always a very accurate indication of how much charge your system actually has - what matters is up time and how long you can go between charges.
Airplane mode is your friend - no real need to disable animation (has nothing to do with idle charge) - the only thing I do is enable airplane mode when away from charger and not using my tab - some of the drain you are reporting could be due to your system scanning for open hotspots.
Also remember all it takes is one poorly coded app to totally screw your battery over - as you are rooted, quite easy to check for apps that relaunch themselves even after closed, apps that want to phone home every 60 seconds - etc.
Would highly recommend you take a close look at any non-stock apps that you have installed.

[Q] Rooting - effect on battery life

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

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

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 )

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.

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.
Click to expand...
Click to collapse
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...

ApokrifX said:
There is system/bin/screenshot
Click to expand...
Click to collapse
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

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

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.

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
Click to expand...
Click to collapse
I've never tried it, actually...

I've seen something happen randomly, I addressed it in another post:
http://forum.xda-developers.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.

Or just turn it off

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?

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?
Click to expand...
Click to collapse
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?
Click to expand...
Click to collapse
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?
Click to expand...
Click to collapse
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.

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

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
Click to expand...
Click to collapse
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.

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.
Click to expand...
Click to collapse
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.

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.
Click to expand...
Click to collapse
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...

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!

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.

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