When browsing these forums, you're bound to run across that thread where a frustrated user is yelling, "I hate my S3 the battery sucks!". It can't be avoided; there is always one similar on the first page of the forum.
You can't help but get sucked in, either because you feel sorry for the poster and want to help, or you're simply curious as to what it could be now. There are always some offering help (sometimes useful; most times not), some sharing that their battery is "just fine" while not offering anything useful, and some just making some statement to the effect that the original poster is an idiot... You know. You've read that thread. You may have even started that thread
. Unfortunately, much of what you read in that thread is misinformation, so, before the next person starts yet another thread on that matter, I'd like to offer some truths about your S3 and its battery.
1. You have a bleeding edge, full featured 2012 Smartphone, with a huge, beautiful screen. It's gonna suck juice. 3G/4G/LTE data running in the background is the other killer of your battery life. Those 2 are the worst offenders, but that's what owning a smartphone is all about. It isn't all bad however, if you're not playing games or posting to Facebook 24/7, it really should last you the day without having to recharge, provided you go through and make sure you apps are set up properly.
2. Will turning off Wi-Fi, GPS, and Bluetooth significantly improve my battery life?
No. In fact, it may shorten it. When your W-Fi is connected, the 3G/4G/LTE radio is basically in "sleep" mode. It's on, but it doesn't actually use any resources unless called up to do so. Since your S3 is getting it's data from Wi-Fi (which uses significantly
less power than your cell radio), the only time your cell radio will use power is if it receives an SMS or other carrier related data that puts it to use.
Wi-Fi, GPS and Bluetooth when they are turned on by themselves don’t drain your battery. What drains your battery are the apps running in the background using whatever connectivity you have turned on. So instead of shutting down features your phone uses, check your apps. Only use those apps that you really need. If you only need data when you open your app, then turn off background syncing, or if you need it, set the time limits to hours, not minutes.
Here's a good example. My phone was connected to Wi-Fi for a couple of minutes. The rest of the time, it was out of range of it's normal AP's, while in range of other AP's it does not normally connect to. Bluetooth was on, however there were no connections.
As you can see, the Wi-Fi and bluetooth used a combined 0.6% of the 61% battery power used over a period of almost 10 hours.
3. Will installing task managers and task killers boost my battery life?
Not really. Android (and yes, even iOS) is "smart" enough to handle task management on their own. And if there is that rare occasion you might have a rogue app, there is always the built in task managers like the one on Android.
4. How about "Conditioning" my battery? Won't that increase my battery capacity?
Battery memory does not exist in today's Li-Ion batteries. You may let it drain down all the way and recharge to 100% so the OS will "learn" your batteries actual capacity, but in general discharging to near 0% repeatedly will lower the life of your battery (which does wear out over the batteries lifetime).
So What Can You Really Do To Make Your Battery Last Longer?
If your battery requires recharging several times a day then it's either an app that is causing that, or efective hardware. Get an app like GSam Battery Monitor (free) or BetterBatteryStats (paid) to find that rogue app, try replacing the battery, or even the handset if nothing else works (as an example, you could have a bad radio that stays on when it shouldn't).
Gsam Battery Monitor Download
Manage the intervals certain apps have to update information (email, social networking, weather). These apps will wake the phone from sleep or stanby states to update. Do you really need to update Facebook every 15 minutes? Set it to every several hours, or even to "Manual".
Turn off vibration. It uses far more juice than ringtones.
If you use your phone indoors a lot, you can set your manual brightness to 20% or so which will give you a moderate boost, and just move the slider up as needed when outside. Removing "live" wallpapers will only save you around 2% or so of your total battery usage, so use at your discretion. If you found one you really like and it's cool to show off, then do so. It's not killing your battery
Turn off unnecessary notifications. It seems as though almost every app checks the Internet in search of updates, news, messages, etc. When it finds something, the app may chime, light up your screen and display a message, make your LED blink, or all of the above. All of this consumes energy.
Most newer Android phones such as the S3 include a Power Saver mode that helps manage the phone's various power-sapping features. Power Saver mode automatically prevents your apps from updating in the background, dims your screen, reduces the screen timeout setting, disables on-screen animations, and turns off vibration. By default, this mode usually turns on when your battery level drops to 20 percent, but you can set it to kick in at 30 percent instead.The sooner the phone switches to Power Saver mode, the longer its battery will last.
Anyway, i'll reiterate.. if you are having battery issues, check your apps! If not apps, try swapping batteries. Apps and defective batteries will account for almost all of the battery drain issues. Hope that helps if you are having problems!
Also, as a last resort, do a factory reset your phone, then check your battery usage. If it's fine, then slowly add apps while continuing to track your battery usage. When you add an app and then the next day notice a significant drain on you battery, you found the culprit!
I should clarify point 2 a bit further.. in addition to SURoot
's comments below, since 3G/4G/LTE is one of the significant drains on the battery, it IS useful to use Airplane Mode (you can quickly access it from one of the buttons in the S3 Notification Bar) when in areas of no coverage, as this prevents the radio from constantly trying to seek a signal where there is none, which will have an adverse affect on the battery.
Keep in mind tho, if you're in a normal coverage area, turning off the data will have negligible effect, however if you're in a weak or non-coverage area, it will prevent excessive drain due to radios constantly trying to find/connect to a signal.
References & Useful Links:
GSam User's Guide
How multitasking really works on Android and iOS | ExtremeTech
Why Your Smartphone Battery Sucks | PCWorld