How to Undervolt the Verizon Samsung Galaxy III (Gain 2 Hours of Battery Life)

There are a lot of ways to gain some battery life, but here at TheUnlockr, we like to push those limits. Undervolting is the process of lowering the voltage that goes to the processor of a device. Normally the manufacturer sets these voltages with some leeway in them for “safety reasons”, we simply lower the voltages to the lowest the phone will tolerate in order to get some well-needed battery life. Root the phone, flash a kernel, then use an app to lower the voltages, here’s how.

This procedure will only work for the Samsung Galaxy S III on Verizon, don’t use it on any other Galaxy S IIIs.

I. Root the Galaxy S III

1. Head to our How To Root the Verizon Galaxy S III on Android 4.1.2, finish that procedure and then head back to this one to continue.

II. Undervolt the Verizon Galaxy S III

1. Click here to download my favorite Kernel and save it to your computer’s desktop.

2. Plug your device in via USB cable.

3. Copy the kernel .zip file over to the root of your device’s storage.

4. Unplug the device, turn it off, and turn it back on by holding down Volume Up, Home, and Power and as soon as the phone vibrates, let go of the Power button but continue to hold the Volume Up and Home buttons until you see the recovery screen.

6. Once it boots in to recovery mode, select Install Zip from SD.

7. Select Choose Zip from SD.

8. Select the kernel .zip file and then select yes to confirm.

9. Hit Go Back until you get to the main recovery screen.

10.  Select Reboot System Now.

11. After it reboots, head to your app drawer and you’ll notice a new app called KTweaker. Open it.

12. Click on Voltages.

13. Hit the Menu button and then select 25 Volts to All Steps 3 times (for a total of 75 mv of undervolting).

14. Hit Apply.

IV. The Results

Using the Quadrant test found in the app store and LAPTOP’s own battery test here are the results we got before and after undervolting.

Quadrant Before	Quadrant After
Battery Before	Battery After

As you can see, the performance on Quadrant only dropped ever so slightly, from 5923 to 5858 after undervolting while battery life increased by 2 hours!