[Upgrading, Modifying and Unlocking] Heatshiver:
I AM NOT RESPONSIBLE FOR ANY NEGATIVE IMPACTS OR CONSEQUENCES ON YOUR PHONE IF YOU SO CHOOSE TO USE THESE TIPS.

I've created a couple threads on the ZTE U950 and LG G2, and one problem is the battery life. The battery cannot come out of these devices and thus we cannot combat this with a bulkier, beefier replacement for heavy usage. Charging constantly is something I try to avoid, so these are a few simple tips that can help optimize your battery life (and that APPLY to ANY PHONE):

TIPS

BATTERY

1a) Buy and download CPU Sleeper (root required). There are two versions, one for dual-cores, and the other for quad-cores. Essentially, when a phone is "sleeping", it is actually still running all its cores, helping drain battery faster. This app turns off all but one core when it is "sleeping" so that your battery is not drained nearly as fast.

BATTERY

1b) To take this step a bit further you can download a free app called Multicore CPU Control. In this app you can control your other cores. You can setup profiles to turn on or off cores, and setup each core with different governors. On my LG G2, I setup a profile to only have one core running at 960MHz (2.2GHz originally) after using the steps from below.

If you plan to only run one core, then you do not need to buy CPU Sleeper.

NOTES ON 1b: Multicore CPU Control is the name when installed, it is called CPU Performance Control Free on the Google Play Store (either name will work on Google Play). The program needs to be turned on after each boot. When first setting up a profile save it and edit it in order to manipulate the other cores available. The app does not always apply a profile even if it has already been selected. To turn on a profile, click on the profile desired and go to the CPU Monitor tab to check if it has been applied. If not, repeat the process until it does (it usually takes me about 3 times at most).

BATTERY/RAM

2) Download Greenify (root required), a great free app! Sometimes a user does not have a ROM with a kill all button, so pesky apps just stay on without consent. This app allows a user to turn off any app that may want to run in your background, and even shows you which apps are currently running. Apps like Facebook, Talkatone, etc. can all be stopped even if your "task killer" supposedly took care of them.

BATTERY

3a) Wakelock Detector-Save Battery is a free app that checks for apps that continue to work while the phone is "asleep". While Greenify will display the most troublesome apps, this app will help discover any other apps that are running without consent.

BATTERY/RAM

3b) If Greenify does not show the apps discovered in Wakelock Detector-Save Battery, then download Disable Services (root required). This free app allows a user to disable an entire service, or just parts of a service that are bothersome. Click on a service/app to find out what other services accompany it. Read the accompanying services and discern whether or not the service is needed. A good place to start in this app is to check any service/app that has a blue number next to it.

EXAMPLE 3b: I use the Outlook app a lot, but sometimes it gets annoying with updates for insignificant email. I can open Wakelock Detector-Save Battery and click the Outlook app. I turn off "AppWidgetUpdateService" to disable Outlook email updates.

Not all services have obvious names, so be careful on system apps if performing trial-and-error.

BATTERY/RAM

3) Buy and download BetterBatteryStats (CPU Spy Reborn/Plus is FREE and only shows CPU states). This app tells me what CPU States are used the most often and is what I download first before my next step. A user can also determine battery-draining apps and turn those off. If turning off those apps is not possible through Settings>Apps just Greenify them!

BATTERY

4) Underclocking. This is an amazing step for saving battery! If you have ran BetterBatteryStats for at least a day, this will come in handy and is highly recommended. You can use numerous programs like SetCPU or Voltage Control to set the clock of the CPU. The key is to find a point that will still be responsive, yet lower than the maximum.

EXAMPLE 4: For this example I will be using my ZTE U950 and Voltage Control. According to BetterBatteryStats, my most used clock was at 1.2GHz and 860MHz. I left my minimum clock at the lowest possible setting, while my maximum clock I changed to 860MHz. I ran this for a few days and saw a noticeable difference in battery life. Another important part to this if choosing the right I/O Scheduler and CPU Governor. I found the default I/O Schedule ("cfq") to perform the best, despite "noop" being good for sluggish memory. "Powersave" is a good Governor at stock CPU speeds, but it will not get a user the savings of power that a step like this will. I tested with this Governor with this step and got horrible reaction times and would often need to restart the phone. The best results I have are with "ondemand" and "interactive". I am currently using "interactive" with a maximum clock of 475MHz! I arrived at that number after checking my BetterBatteryStats while running at 860MHz and found that to be the next most used clock. Now my battery is lasting about twice as long as it normally did! My phone's response time is a bit slower at this low clock speed, but that can combated...

BATTERY/RAM/SPEED

4b) (IF YOU HAVE INIT.D SKIP TO STEP 4c) My LG G2 is underclocked to 960MHz, as noted in step 1b. I am saving quite a bit of battery, but the UI response can lag a lot at times. The use of boot scripts can be helpful to compensate for this. However, my LG G2 does not have init.d support. There are numerous threads that explain how to get init.d support for a lacking Android phone. The simplest method is to install an app from Google Play. I use one called Init.d-Installer just because it forces the phone to reboot once it has installed; others do not seem to do anything to inform a user if they have received init.d support

BATTERY/RAM/SPEED

4c) Download a script called V6 SuperCharger. The thread may seem daunting, but it is fairly easy to install. Download the newest PDF and change it to TXT. Ensure you have init.d support, BusyBox installed (also in the thread if needed), and SuperSU. Run the script in a free app like SManager with SU permissions and follow the instructions. This script gives the ability to enhance speed and power. I install this in order to ensure my UI stays responsive, and LG G2 runs almost at stock speeds (alongside all my other enhancements)!

BATTERY

5) Undervolting (root required/custom kernel required). This is also a great way to save battery. I decrease the voltage in steps of 25 and test from there. If I find no quirks, I leave it. If I find sluggishness or have random phone reboots, I increase by increments of 25 (or 12.5) until I find something stable.

Most phones will not allow undervolting without a custom kernel. To see whether a phone can undervolt or not download, Sytem Tuner. There is a free and paid (Pro) version of this app, but the free one should be sufficient for what we want to do. After installing, open the app and click on the Voltage settings tile on the left-lower side of the screen. All the phone's CPU MHz steps and the amount of voltage applied to each step can be viewed. At the bottom of the screen are buttons to increase or decrease voltage in 12.5 increments (which will apply to all steps). If the -12.5 button is clicked and the values of all the steps drop, then a phone can undervolt. Additionally, System Tuner allows a phone to manually apply undervolting to each step if wanted.

To test undervolting, just push the decrease button until the phone freezes up. There is no harm to your phone or CPU as neither are being overpowered (just the opposite), and a reboot after freezing will reset the phone to default voltage settings. A - 75MHz drop is normal for a phone while remaining stable; and in a lot of cases -100MHz is achievable.

NOTE: Tips #4 & #5 also can be applied to GPUs.

NOTE 2: One thing that should be mentioned is to be careful about putting more than one app that controls CPU clocks. They can read differently and trump the other when used in combination. Instead, install and use one at a time to get more accurate readings. The same should apply to undervolting apps.

BATTERY/RAM

6) A user can change the Dalvik cache a bit to see if that helps optimize RAM, and possibly battery. I did quite a few tests for these to see how they performed. I think the only reason I noticed any changes immediately is because of how far underclocked my CPU is. Anyways, the best results I was able to get with my ZTE U950 was as follows:

124m - dalvik.vm.heapsize (2nd one, not 1st)

8m - dalvik.vm.heapstartsize

For other phones, these are the items to trial-and-error with:

davilk.vm.heapsize (may be more than one at different values)

davilk.vm.heapstartsize

davilk.vm.heapgrowthlimit (may be more than one at different values)

A user can change these settings by downloading an app like Build.Prop from Google Play. I did notice my battery seemed to drain slower with these changed. The RAM was the best optimized for the self-made tests I performed and was nearly the best in all the tests I had ran. A user may or may not notice any differences unless they multitask a lot.

BATTERY/RAM/SPEED

7) All other well-known methods apply as well:

A. Battery Saver apps/settings

B. Battery Calibration apps

C. Refrain from the use of widgets

D. Automatic Brightness apps/settings

E. Small Screen Times before Screen Sleep

F. Turn Off WiFi and/or Data when not needed

G. Task Killers apps/settings