[Epic 4G Q&A, Help & Troubleshooting] RandomKing:
Battery Save Like RandomKing​

I find myself regularly repeating many of these suggestions on many threads to many different people on how to extend your battery life. When not in use, my phone loses at most only 1-2% battery per hour! So I'm making one thread in the Epic forums dedicated to maximizing battery life while trying to explain why these steps will work. Some battery improvements come at the cost of performance or lack of certain services. This must be distinctly understood, or nothing wonderful can come of these steps. :D

Step 1: Brightness & Battery​

Let's face it. Our Android phone screens are huge. This feature is the largest, and completely unavoidable battery-drain. The only way to limit it is to not use the screen... ergo... not use your phone. But that clearly makes no sense, so how to limit that drain? Well, a good step is to turn down your screen's brightness to the lowest you can read clearly, don't hurt your eyes! For night-time use, there's an app that can turn the brightness down even lower called Screen Filter(Thanks to iModMM for the find!). Also, choose a nice dark background, something in the black color range. For all phones, the darker the color, the less brightness used, less power consumed! But for our Epic's Super Amoled screen, specifically, a black pixel is technically an "off" pixel. That's right, every black pixel on your screen is a part of your screen not being powered, since the Super Amoled does not need backlighting. Blackle is also a good alternative to the standard Google site for a black themed search engine, though it doesn't seem to be mobile optimized. Also, lock your screen with that nice little button on the top right side of your phone. Don't wait for it to lock itself! As far as the battery itself goes, charging to 100% can be tricky. The moment that led turns blue, your phone has generally reached 100%, but it will generally trickle charge between 97 and 100 after that. A good way to charge to 100 percent is to use an external charger, which generally come with 1 or 2 spare batteries for about $20. This way, the moment your battery dies, shut down, and pop a fresh one in.

Step 2: Using a Custom Rom​

At this point, there are many Epic 4G custom roms out, and if you're in this forum, you've likely rooted or are trying to root. Well I will not go into rooting directions here. Take a look at one and see how it fare's out-of-the-box for you. If you choose to use my customized rom, you will find a task manager with a preset ignore list, ready to use as a one-tap app-closing widget; as well as the service-freezing patch mentioned below in Step 8 ready for execution through a terminal, and my entire setup(among many other mods, apps, and tweaks tested for the greatest battery performance). These are just roms I've used myself to great results. Many others exist. Updated 7/6:

RandomKing's Customized Rom

2.2.1 EC05 v.1 Plus [Journaled w/Genocide 1.0] [Screenshots]

SyndicateFrozen Rom

2.2.1 EC05 v.1.2

Bonsai Rom

2.2.1 EC05 v.4.1.1 Not Supported on XDA. Sorry.

Midnight Rom

2.2.1 EC05 v.5.3

Step 3: Disable Unnecessary Services​

First and foremost, disable all location services, wifi and gps based. This will affect certain apps like weather apps, you'll simply have to deal with static locations. Next, disable data sync. Contacts will not synchronize with Gmail while this is off. You will have to enable it sporadically. The Gmail app also will not function while this is off, I recommend using the email app and simply adjusting the refresh interval. You can always manually check your own email :p. Likewise, you may put your phone into airplane mode altogether if you don't plan to use it for an extended period of time, such as school, work, swim meet, movies, or on an airplane.

Step 4: Task Killers and JuiceDefender​

First, let's get JuiceDefender out of the way. It's a neat app, and in certain ways, effective. However, it's own effectiveness comes with certain contradictions. It disables nearly all signals, which will include, for example, Google Voice. In my experience, this app hindered certain other services, and if anything may have drawn further on my battery. My recommendation is to stay away from it. Now onto Task Killers, they are good, and they are evil. Let me explain. Many of us may find issues closing all the apps we open, and sometimes forget we left something open. A task killer can easily ensure that you've closed all of your programs. Now onto the bad. Task killers can try to kill certain system services. This is generally BAD. Certain services shouldn't be killed, and others can't be killed, and the ongoing battle only further drains your battery while trying to kill services that AREN'T actually bad. So on that note, the worst part of task killers is AUTO-KILL. Disable it! Kill it! Kill it with FIRE! I use Advanced or Adao Task Killer, with no auto-kill. It is one of the only widgets I use, and I simply tap it before I lock my phone each time.

Step 5: Widgets​

If you don't need them, don't use them. Almost all widgets make continuous unnecessary calls to the Android system, and this can be a huge battery draw. Even simple widgets. Through all my testing, there's only 2 widgets I have approved thus far: Advanced Task Killer, Power Control. Other disapproved widgets: Pandora, Winamp, Weather(ALL OF THEM), etc.

Step 6: SetCpu, Voltage Control, and Over/Underclocking​

As with much of this thread, this is opinionated and empirical theories. Through my testing, Overclocking is unnecessary, and guaranteed to draw on the battery. Most of these roms come from fantastic devs and are, by default, blazingly fast. Overclocking is completely redundant in my opinion, and I'm generally all about speed. Underclocking/undervolting may preserve more battery, but my opinion on the matter is similar to my feeling on widgets. If you don't need it, don't do it. If you feel the need to use these apps, a generally accepted setting for battery preservation is to undervolt to 800 max. and 100 min. (if your phone can handle it, some may experience wake-locks, raise min. to 200) on conservative governor, adjusting your profiles for when the phone is locked, unlocked and etc.

Step 7: Unnecessary Apps​

Free apps are great, aren't they? But how many have you gathered, just because they're free? Now how many of those don't you use, but regularly draw on your phone regardless. There's an easy way to roughly check. Open your settings. Now go to Applications. Manage Applications. Take a look at which are running that you have not opened. Using a task killer prior, and waiting a couple minutes to see what re-opens may be a good way to check which apps are continuously running in the background and evaluate if they can be removed.

Facebook --- Notorious for running in the background. Disabling notifications may help.

Latitude --- Largest offender of location service usage. Neat app. Huge battery hog.

QIK/Fring --- Any video chatter really. If you don't use them, remove or disable them.

Browser --- Large ram usage. Try Dolphin Mini or Miren.​

Step 8: Freeze Services​

Using Titanium Backup Pro, MyBackup Pro, or Bloat Freezer (yes, non-free apps) freeze any of the following services:

sns --- (Will disable sns)

snsaccount --- (Will disable Facebook contact integration)

drm --- (May affect media programs like mediahub)

drmcontent --- (May affect media programs like mediahub)

systemupdater --- (Best disabled if on custom rom)​

Enter the following commands into the Android Terminal to manually freeze the above services:

su
pm disable com.sec.android.providers.drm
pm disable com.sec.android.app.sns
pm disable com.samsung

Simply enter the previous commands into the Android Terminal while substituting "enable" for "disable" to manually defrost these.

If you would like a shortcut for this method, check out the patch in This Thread Also Included In RandomKing's Rom..​

Step 9: Journaling​

Journaling... some love it, some hate it. The fact remains, journaling enables extra write cycles. While this will prevent data loss, it also means more cpu usage. It follows that battery should last longer with journaling disabled. You can use chris41g's mod HERE to turn Journaling on/off at will.

Step 10: Turn it Off and Spend Time With Loved Ones​

That's right. You're obsessing with your phone. Leave it be. Do something meaningful and memorable. Have fun with life! This is just a phone. :D

More coming as it comes to me! Including mods, apps, etc. aimed at improving battery life. Feel free to leave your own suggestions or questions! If this guide and it's features have helped you in anyway, leave THANKS so I know whether or not to keep up on it!​