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Samsung Galaxy S2 Battery Drain Fix / Work-Around

alre101

Lurker
Jan 16, 2012
1
8
I have found a work around for the battery drain issues after the 2.3.6 update to my GS2. I consider this to be a work-around, because an actual fix would involve someone at Google or Samsung actually correcting the buggy code. I am dividing this up into several sections that describe the work around and the rationale behind it. I'll start with the fix and save the details for later. ************ The Problem After the 2.3.6 update I noticed a sharp decrease in battery life. I went from being at more than 70% battery at the end of the day at work to being at 50% or less. I tend to keep WiFi on all the time because I connect to the network at my house, the AT&T store that is next to the place where I stop for a bagel in the morning, and at the office. I noticed that instead of "Display" being the biggest battery hog (as I was used to), it was now "Android OS". I was quite concerned because I was about to go on a business trip, and would need my phone for checking email, returning phone calls, etc. While on the trip I kept WiFi off, and I noticed a significant improvement in battery life, even though I was checking email regularly via the 4G connection. That was the first piece of evidence that the root cause f the problem was related to WiFi. ************ The Work Around The following worked for me, and I think will work for others. 1. Go to Settings -> Wireless and Network -> Wi-Fi Settings. Tap the menu key and then Advanced -> Wi-Fi Sleep Policy. Select Never. (This is counter intuitive, but I will explain the reason for this below.) 2. Download a 3rd party battery manager that can control WiFi. I am using Battery Defender, which is free. Juice Defender Plus and Ultimate should also work. (I don't think that the free version of Juice Defender controls WiFi.) If the market tells you that Juice Defender is not compatible with your device, I think it is because AT&T doesn't want you to use it. You can probably side load it, or pop out your SIM card and download it over a WiFi connection. 3. Set up the battery manager of your choice to control your WiFi connection by turning it off when the screen is off. Battery Defender is a bit of a blunt instrument in the sense that when your screen is off, WiFi is off. Juice Defender is a little more sophisticated because it turns WiFi on periodically (every 15 minutes) and allows background applications to connect briefly. If you rely on push e-mail and/or social network updates, you will probably prefer Juice Defender. 4. Enjoy improved battery life where your Display now is the biggest consumer of power. ************* Why This Works Based on reading a number of posts in this forum and others, there is good evidence that there is a bug in the operating system's Suspend process. Normally you would let the operating system manage the WiFi connection, and it can be set up to turn the WiFi off when the screen is off (that is one of the options in the WiFi Sleep policy settings). What appears to be happening is that the Suspend process has a bug and when it shuts off the WiFi radio it goes into an infinite loop of some sort that burns processor cycles and uses a lot of power. This shows up on the battery usage screen as "Android OS". By telling the operating system to never put the WiFi to sleep, the buggy Suspend process never runs. By itself, this would involve a trade-off between the power consumed by the WiFi radio and the buggy suspend (I actually think that leaving WiFi on all the time would use less power). By installing the 3rd party battery manager you are having another program sneak in and turn the WiFi off at the hardware level. The operating system is not involved, and the Suspend process does not start. ************** I hope this help those of you who are having problems. Al
 
it says use juice defender.

edit: sorry that was a little snarky. It says that the wifi sleep gets caught in an infinite loop that drains battery power and shows up as android os. The way to get around it is to use a third party wifi manager, such as juice defender to get around the problem. Hope that helps!

Oh, I didn't take it snarky. I wasn't trying to be an ass myself. A) I'm dyslexic and B) I'm an old 40-something fart. Trying to read that, would lead to a migraine the size of texas.

That you much for breaking it down!
 
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you're welcome. I just don't know if juice defender is the one to use. Since it is beta only, I am reluctant to use it. Any other ideas for a good manager? and will they conflict with att wifi manager which I just installed for some reason?

Don't take my word for it, because I honestly haven't investigated either app. However, I installed the AT&T app also and my perception, is that it should basically take care of the issue. Juice Defender seems like overkill to me, for this particular problem.

Though, again... I don't know enough about Juice Defender. I always thought its basically a task manager and Android does not need task managers.
 
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Al, there is another similar workaround. ATT has placed an app in the Android Market called AT&T Smart Wi-Fi which connects the Wi-Fi only when near previously accepted connections. I believe it checks when screen is on and sleeps the Wi-Fi otherwise.

it says use juice defender.

edit: sorry that was a little snarky. It says that the wifi sleep gets caught in an infinite loop that drains battery power and shows up as android os. The way to get around it is to use a third party wifi manager, such as juice defender to get around the problem. Hope that helps!

Thank you both for this information, will try it out and see what the happs is. I too barely skimmed through that stuff at the top heh - your posts helped explain it more succinctly. (Sorry OP :( )
 
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Al, there is another similar workaround. ATT has placed an app in the Android Market called AT&T Smart Wi-Fi which connects the Wi-Fi only when near previously accepted connections. I believe it checks when screen is on and sleeps the Wi-Fi otherwise.

Ok, so do I just download the app and it does what it's supposed to do on its own? or do I need to set it up or something?

I downloaded, but I'm just not sure how to use it.

Thanks!
 
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OK so even with the ATT wifi app and juicedefender installed, I only got 14hrs out of my battery and it wasn't used for web surfing at all.
This seems like some sort of memory/cpu leak because even though juicedefender is shutting down the wireless, but enabling it every half hour to update apps, it isn't lowering the OS. My OS was still running at over 90%.

I'm doing a test today. I disabled syncing to gmail, uninstalled juicedefender and att wifi app, turned off wifi, and then power cycled my phone. Will see how long it lasts.
 
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Tiger, I just installed the AT&T app and let it do its thing (no setup). Just run it when you reboot or start the phone to make sure it is running.

G, I think your suggestion would still let the WiFi run (scan) if you're not in one of your previously accepted WiFi access points / routers / places. If I understand the AT&T app, - screen on check - not a favorite WiFi location, then sleep WiFi - Favorite: -> wake up WiFi & connect.
 
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you're welcome. I just don't know if juice defender is the one to use. Since it is beta only, I am reluctant to use it. Any other ideas for a good manager? and will they conflict with att wifi manager which I just installed for some reason?

Not sure where you got Juice Defender is beta only. I'm running version 3.9.4. I downloaded it from the market in Nov. and just kept updating as they came available. I'm running the free version not the plus version.
 
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I'm not getting something:

Why not just go into Settings/Wireless and Network/Wi-Fi settings/ then Menu/Advanced and go to Wi-Fi sleep policy and select:

"When screen turns off".

Isn't that the same thing you guys are trying to do without needing a 3rd party app?

Because all of us, already have it setup like that. There is a wifi bug in 2.3.6
 
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Not sure where you got Juice Defender is beta only. I'm running version 3.9.4. I downloaded it from the market in Nov. and just kept updating as they came available. I'm running the free version not the plus version.

If you check the market on your phone and try to upgrade to the pro version, it says its not available for our phones, which is horse crap, because all it does, is unlock the features.
 
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For the tl;dr people,

OP says to use JuiceDefender, but you will need PLUS or ULTIMATE version to ctrl Wifi.
Or to use Battery Defender.

He also said to try out the AT&T WIFI app, but one person said it is has not solved the issue.

Issue lies with Wifi eating up the battery life. Get JuiceDefender PLUS or Battery Defender.
 
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