[GUIDE] Galaxy Nexus Battery Life [12/27/11]

• High "Android OS" Battery % usage. Possible remedies include settings->Wifi->Advanced(menu)->Keep Wifi on ALWAYS when sleeping; Trying alternative kernels from the dev section; although 4.0.3 may have some improvements, early leaks are not yeilding substantial changes.
• High "Media Server" battery % usage when using a media app with audio, video, etc.
• High Preset voltage table in kernel can be fixed with UC Kernels, but proceed cautiously.

• Screen brightness: Using the lowest comfortable setting will save a good bit of battery, espescially on such a large screen. App LogGraph can be used to change auto-brightness levels
• Haptic feedback: Switch this setting off (Settings->Sound->Vibrate on touch). You may need to turn this off in alternative keyboards. Vibrations on button press, unlock, etc will use power for the vibrating motor. This includes vibrating for a call or text.
• Button Sounds: Switch this setting off (Settings->Sound->"Dial pad touch tones"; "Touch Sounds"; "Screen Lock Sounds"). Speakers are small electro-magnets and require energy to move, consuming a small amount of power.
• Sync: The more frequently your apps sync the more energy will be consumed. Turn off unnecessary syncs and reduce excessive syncing (Settings->Accounts & Sync->...) Alternative apps such as Juice Defender and Tasker can be used to control sync settings. Some ROMs are now incorporating this feature as well.
• Antennas: The short of it: Use Wifi as often as you can, it scans for a connection less often than mobile data. BT, and GPS antennas use very little power when idling. This is the most often confused aspect of battery life. Read more in the "Nitty Gritty" section.
• Live wallpaper: Requires greater CPU usage to run, and currently ICS lags in this CPU processing, as demonstrated when switching an older phone over to ICS and finding lag in the wallpaper.
• Widgets: Higher refresh rates, sync intervals and greater changes in the widgets will consume energy more rapidly.
• AMOLED Screen consume less power when displaying black.
• Auto Rotate uses greater CPU and changes screen.

• Battery % graph, which shows the amount of battery used since unplugged, as well as a time on battery.
• Individual App/Process battery usage. The Percentage here corresponds to the amount of battery used by the App/Process of the already used battery. NOT the total battery capacity.

• CPU Total - Total CPU usage in time
• CPU Foreground Total - Total CPU usage while app is visible to user
• Keep Awake - Total time app prevented phone from going into “Deep Sleep”
• Screen on Time - Time screen was active (duh...)
• Time on - Time process has been running

• Battery % usage over very long periods of time
• Battery voltage recording
• Battery drain (mah and watts)
• Battery capacity estimates (both in time and mah)
• Battery conditioning status
• Support for multiple batteries
• Estimates for various conditions (watching video, audio, games, etc)

• Reducing maximum clock speed.
• Using cpu governer that keep the CPU at lower frequencies for longer periods of time. Power save, conservative, smartass, etc take different theories as how to achieve the best ballance between performance and energy efficiency.

• Consumes more energy per time when trasmitting than mobile data, BUT...
• Takes less time to transmit data, espescially large files, so it consumes overall less energy.
• Wifi scans for a connection and pings the router less often than mobile data, thus consuming less energy at idle

• Consumes a small amount of power at idle to connect to new devices
• Scanning for deveices consumes more energy
• While connected, very little energy is consumed unless data is transmitted.

• Unless an application specifically invokes the GPS antenna, it will not consume power
• Using constant GPS updates (as in Navigation apps) will consume a large amount of power
• Some apps will have bugs in them which will keep GPS on indefinitely. Try reinstalling those applications first, then remove if necessary.

• 2G antennas consume the LEAST amount of energy at idle, but because they take so long to trasmit data, they can kill your battery.
• 3G antennas are Ok at idle, but take less time to transmit data, so are the best all around for traveling around metropilitan areas.
• 4G Antennas are FAST, but consume the most power. Best to leave these off when in transit, and used for stationary, stable connections
• All Antennas consume much more power idling in areas of bad reception. So if you know you're going somewhere with poor reception, and don't need data, turn it off until needed (Settings->Wireless&Networks ->More ->Mobile Networks-> "Data Enabled"; "Data Roming" OFF; "Use Only 2G Networks"

NOTE: The Baseband is defined by 3 sets of codes. The first two are the Country Code, the next 2 denote the Year and Month (KK = 2011 November) and the last number denotes the Revision.

Country Code:

CE---> Belgium, Luxembourg, Netherlands
DC---> Thailand
DD---> India
DX---> Indonesia, Malaysia, Philippines, Singapore, Vietnam
DZ---> Malaysia, Singapore
JA---> South Africa
JC---> Algeria, Morocco, Nigeria, South Africa, Tunisia
JP---> Arabic, Algeria, Egypt, Iran, Iraq, Kuwait, Morocco, Nigeria, Oman, Pakistan, Saudi Arabia, Syria
JV---> Tunisia, Turkey
UG---> North America
UH---> Latin America, The Caribbean
XE--->	Bulgaria, Estonia, Kazakhstan, Latvia, Lithuania, Russia, Ukraine
XX---> Austria, Belgium, France, Germany, Hungary, United Kingdom
XW---> Austria, Belgium, France, Germany, Hungary, Italy, Nordic, Spain, United Kingdom
ZC---> China, Hong Kong
ZH---> Hong Kong
ZS---> China, Hong Kong
ZT---> Taiwan

wanderfowl said:

Very nice thread. You might want to mention JuiceDefender as well, as that's a really useful utility too.

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matt2053 said:

I think this should be mentioned:

USE WIFI!!!

Using 3G uses about double the battery of wifi. Using 4G uses about triple the battery of wifi. If there is wifi near you, use it! Use wifi at work and at home if at all possible.

Sent from my Galaxy Nexus using XDA App

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gogol said:

You should also mention this on-going issue with battery life:

http://code.google.com/p/android/issues/detail?id=22878

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wanderfowl said:

For what its worth, my preliminary experiments seem to be showing that on the Galaxy Nexus, JuiceDefender uses more battery than it saves. FYI

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jnyce87 said:

is there any way to turn off the media server?

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jnyce87 said:

my battery is very inconsistent and at times I have horrendous drain

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Sal Khan said:

Not that it'll mean much, but Wi-Fi is the battery saver on this phone for me.

Light use all day, screen at 100% (which I turn off manually every time before putting it down)
Everything on but bluetooth

Did some MP3 playback (2 hours), Lots of Tweetdeck, some maps - all while actually NOT on wifi (about 3 hours total) - the rest of the time I was at home.

I got about 18 hours before the phone shut off from a dead battery. The same without Wifi with 3G only would net me 8'ish. With 4G about 6ish - all with screen set to Auto.

So my casual and un-scienitific observation for my phone shows that there is something to be said about using WiFI instead of cellular service. I'll try and narrow it down further this week since I'm on vacation.

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