1. StevenX's Avatar
    I'm a new Galaxy S II (and new Android) user, and am a bit disappointed in the battery life of my new phone. It was running down extremely quickly yesterday, only lasting about 12 hours with relatively normal use (sending half a dozen texts, downloading 2 apps, checking Facebook and Twitter once an hour or so for a couple of minutes throughout the day). I allowed the phone to discharge completely and charged it fully last night, but this morning nothing seems to have improved. I burned up 10% of the battery in half an hour sending 2 texts, checking my emails, Facebook and Twitter and downloading and trying out a couple of apps.

    I'm anxious to know if there's a bit of a burn-in time with the battery on this thing - does it get better after a few charges? I see a lot of people saying they can have the phone on for a few days in some cases, but that's definitely not my experience thus far.

    I've installed JuiceDefender (balanced profile), AutoKiller Memory and Advanced Task Killer to try to sort things out but none of them seem to having too much effect and to be quite honest I'd rather not have to compromise my experience by running a number of apps like this to try to extend my battery life at all (nor do I want to have to turn the brightness right down to an unusable level, or set black wallpapers for example).

    Does anyone have any real advice on this? I'm starting to think that switching ROMs might be worthwhile? I see that the leaked 2.3.4 ROM seems to have better battery life - is this correct? I'm a bit reluctant to switch to any other unofficial ROMs as there are so many I wouldn't know where to start. It seems they all make a lot of changes but I'd want to keep as close to the stock feel as possible, just with better battery life.
    09-17-2011 04:25 AM
  2. D-Caf's Avatar
    I'm not sure, I tend to get better battery life than that. I've remained stock and have a lot of stuff on at the same time, check this thread for details on my usage:
    http://forums.androidcentral.com/sam...-use-sgs2.html

    One thing I would do is remove JuiceDefender, AutoKiller Memory and Advanced Task Killer. Juice defender might be alright (never used it), but I would definitely drop the other two, they are likely to eat up more resources overall than they save.
    StevenX likes this.
    09-17-2011 09:23 AM
  3. the.ak.hermit's Avatar
    I have had the S2 for about a week and a half, and the one thing that improved my battery life significantly was turning the GPS off unless I am using it. It finds my general location via towers, and that is good enough unless I am trying to find my exact location or navigating.

    My battery lasts all day easily, 10 to 12 hours, and still at 50 percent. I am a moderate user.

    Also on modern batteries, you DO NOT fully discharge and power cycle.

    I don't have any task killers or anything like that running in the background.
    StevenX likes this.
    09-17-2011 09:48 AM
  4. StevenX's Avatar
    I'm not sure, I tend to get better battery life than that. I've remained stock and have a lot of stuff on at the same time, check this thread for details on my usage:
    http://forums.androidcentral.com/sam...-use-sgs2.html

    One thing I would do is remove JuiceDefender, AutoKiller Memory and Advanced Task Killer. Juice defender might be alright (never used it), but I would definitely drop the other two, they are likely to eat up more resources overall than they save.
    I've decided to remove all three as from reading up online it seemed to be the general consensus that they did more harm than good.

    I have had the S2 for about a week and a half, and the one thing that improved my battery life significantly was turning the GPS off unless I am using it. It finds my general location via towers, and that is good enough unless I am trying to find my exact location or navigating.

    My battery lasts all day easily, 10 to 12 hours, and still at 50 percent. I am a moderate user.

    Also on modern batteries, you DO NOT fully discharge and power cycle.

    I don't have any task killers or anything like that running in the background.
    I did notice that on my first day the GPS icon kept flashing up in the top bar for some reason, despite me not being in any location-aware apps. Does this mean anything? Or just that GPS is enabled? I've not seen this happen since, so maybe something weird was going on and that was eating up the battery a bit.
    09-17-2011 10:56 AM
  5. the.ak.hermit's Avatar
    If you pull down from the top, you can disable it. When mine is enabled, it stays green, and my battery drains faster, which tells me it is locked on to satellites even when I am not in a gps app.

    I have had excellent battery life with it disabled.

    Also, I don't leave WIFI enabled, unless I know there is a signal nearby.
    09-17-2011 02:19 PM
  6. Meiji's Avatar
    There are indeed some ways to improve your battery life, wich, in a monster phone like the Galaxy S II, is sometimes difficult at first. I come from a Galaxy S, and could manage to keep a good battery life for about 2 days. Then I bought a Galaxy S II and battery used to hardly last half a day, but after some configurations, it now easily lasts the whole day and half of the next (unless you're playing some HD game or something that consumes battery a lot).

    1) Turn off your WiFi unless you're using it.
    2) Turn off GPS as well unless you're using it (though most of the time I have my GPS on).
    3) Turn off your bluetooth unless you use it.
    4) Go to Settings > Wireless and network > WiFi settings.. then uncheck Network Notification (this drains your battery as hell since it's all the time checking for existing WiFi conections).
    5) Go to Settings > Wireless and network > WiFi settings.. then press the Menu button > Advanced > WiFi sleep policy.. and check Never.
    6) Go to Settings > Accounts and Sync.. then uncheck Auto-sync (also drains battery, it's all the time auto-syncing to your Facebook, Google, etc accounts), if you add new contacts to Google for example, better is to sync manually.

    Also, if you don't have a data plan, then you can go to Settings > Wireless and Network > Mobile Networks.. then uncheck Use Packet Data.
    But if you do have a data plan, I recommend to use an app to control its use. APNdroid is a good app for that. After download it, you can use its widget and activate/deactivate it each time you need/want it (although this might get pointless if you have unlimited data plan, but could help save some battery life anyways).

    Btw.. you did good by uninstalling JuiceDefender, AutoKilling Memory and Advance Task Killer. They are useless in my personal opinion. On the other hand, you could try Android Assistant and Watchdog. These apps could help you check the performance of running apps, battery, cpu, etc., and only get ride of an app if it's malfunctioning or doing many more cpu cycles than it should, etc.

    Hope this helps! Cheers!!
    StevenX likes this.
    09-18-2011 01:52 PM
  7. the.ak.hermit's Avatar
    I used WIFI hotspot yesterday, and I would say that it drains the battery faster than anything else, but works great with my Playbook when I am sitting in the car.
    09-18-2011 02:56 PM
  8. StevenX's Avatar
    Thanks for all your suggestions! I've toggled a few of the settings mentioned here which don't make any difference to my usage (the wifi notifications is a great point, Meji - and those notifications are annoying as hell anyway! That setting should be off by default!). Having read up on rooting and so on online I've rooted, installed a new kernel and set some SetCPU profiles which are really helping too - having done all of this I'm actually becoming quickly very impressed with what life I can achieve from it! It's a shame Samsung doesn't have some of these types of mods enabled by default...
    09-19-2011 12:06 PM
  9. brendanbrendan's Avatar
    Disable fast dormancy:
    1: launch phone app
    2: dial *#9900#
    3: click "disable fast dormancy"
    4: click "exit"

    Not sure what it changes but definitely improves daily battery savings.

    Sent from my GT-P7500M using Tapatalk
    09-21-2011 02:07 PM
  10. Happyangel's Avatar
    I think you should try out a custom rom (make sure to backup your stock rom first)
    09-23-2011 12:05 AM
  11. IcebergMike's Avatar
    Really simple but made a big difference in battery usage once I did this:

    Settings>Display>Brightness>Automatic brightness
    Also: >Display>Autoadjust screen power - check it
    10-07-2011 12:07 PM
  12. Zaen Zar's Avatar
    Disable fast dormancy:
    1: launch phone app
    2: dial *#9900#
    3: click "disable fast dormancy"
    4: click "exit"

    Not sure what it changes but definitely improves daily battery savings.

    Sent from my GT-P7500M using Tapatalk




    What the heck IS that!?
    11-03-2011 07:55 AM
  13. cmunic8r99's Avatar
    Accidental discharge. Ignore this.
    11-15-2011 04:15 PM
  14. Fr3lncr#AC's Avatar
    Not sure what OS version the AT&T S2's come with but I also got a jump in battery life going from 2.3.3 to 2.3.5. I would use up about 15-20% of my battery on the way into work on the bus and after 2.3.5 it would be closer to 5-10%. 2.3.5 also has a Power Saving function that 2.3.3 didn't have.

    The battery saving tips that Meiji mentions above also helped me.
    11-16-2011 06:05 AM
  15. Shermdiggity's Avatar
    The suggestions made so far in this thread are great. I've incorporated most of them myself and getting great results.

    However, I can't speak for the other Apps, but I've had tremendous success with Juice Defender as well. I started with the free version, but paid the $4.99 for the Ultimate version. I'm a moderate and occasionally heavy data user, yet here lately I'm getting about 30 hours of battery life. It's awesome.
    11-16-2011 10:41 PM
  16. Lavitapostandroid's Avatar
    I use juice defender. I get a full day out of a charge. Set it and forget it.

    Sent from my SAMSUNG Galaxy S II
    11-19-2011 07:20 PM
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