NFC Battery Drain Documentation - Samsung Galaxy Nexus

All you ever wanted to know about NFC and battery drain.
Here's a starter:
A typical NFC transceiver draws ~50mA of current when powered up. For reference, this equates to around 25% of the total consumption of a typical smartphone with the screen powered on.
Left unchecked, this could have noticeable, adverse effect on battery life.
However, there are optimization techniques that can significantly reduce the effects of NFC on battery life. For instance, the Android NFC subsystem carries out the following:
Intelligent polling - Android doesn't leave the NFC transceiver running at all times, instead it polls for tags at a rate around ~10Hz to conserve battery life. Maybe a feature in future ROMs would be the ability to change the polling frequency down to 1Hz.
Polling disabled on screen lock - when the screen is locked Android ceases to poll for tags, however card emulation continues (this is how
Google Wallet functions even when the screen is locked) .
Screen off = NFC off - the NFC radio is powered down when the screen is locked.
Click to expand...
Click to collapse

Related

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

This guide is a work in progress, please contribute to it so we can have a central place for battery info!
Table of Contents:
1. Quick Tips
2. Monitoring Battery Usage
3.The Nitty-Gritty Details
4.Frequently Asked Questions
5.References
6.Changelog
Quick Tips
NOTE: As with many devices in their early days, there seems to be a few bugs needing to be worked out. Some of which include:
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.
http://code.google.com/p/android/issues/detail?id=22878
Battery Capacities. NOTE: The batteries are NOT interchangeable between GSM and LTE!
GSM: 1750mah
LTE: 1850mah
LTE extended battery: 2100mah
GSM extended battery: 2000mah
Settings that use us battery:
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.
Apps for reducing battery usage:
Juice Defender - Very easy interface for switching wifi/bt/3g/etc on and off to save battery. Great first start. WARNING: Some users report greater battery consumption when USING juice defender. This may be due to certain settings they have or the app itself.
Tasker -Much more advanced, and less user friendly application for automating processes on android. Can be used to closely control the behavior of your phone.
Table of Contents:
1. Quick Tips
2. Monitoring Battery Usage
3.The Nitty-Gritty Details
4.Frequently Asked Questions
5.References
6.Changelog
Battery Monitoring
Standard Android OS Battery Usage Utility
Settings -> Battery
When entering this section, you will see two distinct sections:
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.
Clicking on a process or app will bring up more details on that process. Some definitions used are as follows:
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 Monitor Widget
I highly recommend this app. It gives you a wealth of information.
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)
CPU Spy
I use this for one purpose: to see how much time my phone spends in each CPU frequency. And more importantly, how much time it is in deep sleep. Deep Sleep is the condition in which the phone suspends as much activity as it can. This is the lowest consumption state your phone can be in... besides being off
Table of Contents:
1. Quick Tips
2. Monitoring Battery Usage
3.The Nitty-Gritty Details
4.Frequently Asked Questions
5.References
6.Changelog
The Nitty Gritty
The key here is to think back to physics class. We have an energy storage device, and a few devices that consume energy and varying rates (power - NRG/Time)
Kernel Stuff
Adjusting Clock Speed - CPU and GPU frequenxcies will directly effect energy consumption when in use. That is to say, if your phone is just idling with the screen on, the CPU is using very little power. Much more is being eaten by the screen. There are two approaches to saving power in clock speed, both of which aim to reduce the time spent at higher frequencies.:
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.
[TIP] Use CPU spy to check much time the CPU spends in each frequency, and more importantly in deep sleep.
Adjustiing CPU Voltages - Using a kernel with an unlocked voltage table and setcpu to specify voltages for each individual frequency can lead to significant power savings from the CPU. When experimenting with voltages, do not check “set at boot” until you have established stable voltages.
Suggested Voltage testing: Coming soon...
Antennas
Wifi
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
Bluetooth
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.
GPS
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.
Mobile Data
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"
Radios
Radios control how your phone connects to the mobile network. Specifically which proticols to use in which regions as well as how often to try to reconnect. This can lead to better or worse battery, signal, and network speeds.
Code:
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
Table of Contents:
1. Quick Tips
2. Monitoring Battery Usage
3.The Nitty-Gritty Details
4.Frequently Asked Questions
5.References
6.Changelog
Frequently Asked Questions
Q: I just flashed a new rom or update, could that be the cause of battery issues?
A: Absolutely! A bad download, experimental features, or even settings that are not friendly with your device can greatly impact your battery life.
Q: What battery life should I expect out of my device?
A: That level can vary widely by usage. Generally, screen on time of 4+ hours is considered good.
Table of Contents:
1. Quick Tips
2. Monitoring Battery Usage
3.The Nitty-Gritty Details
4.Frequently Asked Questions
5.References
6.Changelog
References
References:
Better Battery Stats - http://forum.xda-developers.com/showthread.php?t=1179809&highlight=battery
Battery Calibration The easy way - http://forum.xda-developers.com/showthread.php?t=1024867&highlight=battery
Tasker Sync Control - http://forum.xda-developers.com/showthread.php?t=1031743&highlight=battery
Tips Battery Usage - http://forum.xda-developers.com/showthread.php?t=1374133&highlight=battery
SetCPU - https://market.android.com/details?id=com.mhuang.overclocking
Autostarts - https://market.android.com/details?id=com.elsdoerfer.android.autostarts
List of Battery wasting apps - http://forum.xda-developers.com/showthread.php?t=1251897&highlight=battery
Build.prop & init.d stuff - http://forum.xda-developers.com/showthread.php?t=1289554&highlight=battery
Battery monitor Widget - https://market.android.com/details?...d_apps#?t=W251bGwsMSwxLDEwOSwiY2NjNzEuYm13Il0.
System Tuner - https://market.android.com/details?...eloper#?t=W251bGwsMSwxLDEwMiwiY2NjNzEucG13Il0.
CPU Spy - https://market.android.com/details?id=com.bvalosek.cpuspy&hl=en
Juice Defender - https://market.android.com/details?...xLDEsImNvbS5sYXRlZHJvaWQuanVpY2VkZWZlbmRlciJd
Changelog
Code:
12/19/11 Basic Guide structure, info, etc
12/27/11 Added notes for current GNex issues; updated Nitty Gritty w/ antennas; added guides for settings.
Very nice thread. You might want to mention JuiceDefender as well, as that's a really useful utility too.
wanderfowl said:
Very nice thread. You might want to mention JuiceDefender as well, as that's a really useful utility too.
Click to expand...
Click to collapse
Thanks, added that and tasker to the first post as apps that can help save battery
why many posts...
Hey instaed of reposting everything can you try putting all together in one post..???
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
You should also mention this on-going issue with battery life:
http://code.google.com/p/android/issues/detail?id=22878
For what its worth, my preliminary experiments seem to be showing that on the Galaxy Nexus, JuiceDefender uses more battery than it saves. FYI
is there any way to turn off the media server?
my battery is very inconsistent and at times I have horrendous drain
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)
E
verything 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.
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
Click to expand...
Click to collapse
Absolutely! Added a note for it, and a section in "Nitty Gritty" about all the antennas.
gogol said:
You should also mention this on-going issue with battery life:
http://code.google.com/p/android/issues/detail?id=22878
Click to expand...
Click to collapse
Added, thank you!
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
Click to expand...
Click to collapse
I had the same experience, but I like Tasker for finer grain control anyway. The main thing to be weary of is Location-based settings. Tasker has a guide called "Location Without Tears" to explain it.
jnyce87 said:
is there any way to turn off the media server?
Click to expand...
Click to collapse
Not currently. You could freeze it through titanium backup, but that would break a bunch of apps. Some devs are working on fixes for this and Android OS
jnyce87 said:
my battery is very inconsistent and at times I have horrendous drain
Click to expand...
Click to collapse
All Three attached photos show pretty good battery life. Keep in mind: for a device early in its development, 12 hours is great!
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.
Click to expand...
Click to collapse
Thank you for the perspective. I've added some sections referencing these issues.
I've been really surprised with the reviews about the battery life. So far I got the phone for a month ( in UK) and battery life is pretty good.
I have sync accounts, use the phone moderately (about 3 to 4 hours with screen on per day), no battery saving app or anything.
My daily routine is to unplug my phone from it's charger a 7am and every day I end up at night around 11pm with a battery around 40%... Some day I will forgot to plug it at night and be able to have it last almost for the entire next day (being careful though)
first week wasn't so good but after a few days battery improved significantly.
to me the key to save tons of battery life was to set the screen brightness to the second lowest level. It's really bright enough to my taste and literally since then I never got the phone to drain off within 20 hours after a full charge.
Also I have the wifi always on as mentioned earlier on the thread.
I have the GSM Nexus. I have had the phone for 1 week. My phone for phone calls, which drains the battery pretty quickly has not been real heavy as of late, but I have been typically seeing a 3% drop per hour of use. So right now I am at 78%, and have been up for 6h 48m.
Overall I am very happy with my battery life.
JOHN
Tubes6al4v said:
The key here is to think back to physics class. We have an energy storage device, and a few devices that consume energy and varying rates (power - NRG/Time)
...
Reducing maximum clock speed.
Click to expand...
Click to collapse
Is this really a good idea? Consider the following:
Higher clock speed means getting things done quicker. If the phone is running at 1400MHz with a voltage of 1225mV for one second, instead of running two seconds at 700MHz with a voltage of 900mV, what will demand the most energy?
(Voltages are the ones I'm using on my OC/UV'd Nexus, not the stock ones which are *way* high)
I'd rather focus on lowering the CPU voltage as low as it goes without instability than waste time with a slow phone
If i use my GNex normal i charge every two days, i like maximum display

[GUIDE] To Maximize Galaxy Nexus Battery

This guide is not meant to be as a whole and is not meant to be followed from beginning to end. There are several recommendations based on my own experience, some of them will give you big battery savings, some of them minor ones; I tried to recopile every config that helps to save battery, but every config is not suitable for everyone. (I´ll point it at the beginning of every section in bold blue).
You'll need a Rooted Galaxy Nexus, with a custom ROM and a custom Kernel.
The custom ROM will give you the ability to make a deep configuration of the device in terms of options. I'm actually using Liquidsmooth v1.25, but AOKP, CM9 and SlimICS have the same options (if not more) than my actual.
Some custom Kernels will give you the ability to change the CPU frequency and voltage, kernels are the main reason of some drainings or fantastic battery life, choose wise.
The normal Galaxy Nexus battery life is about 4 hours screen time. If you are not achieving this, the main reasons could be:
1. Some apps are draining your battery due to a continuous use (no deep sleep or continuous wake ups).
2. Screen too bright.
3. Bad kernels with draining problems.
4. Weak signal connections.
This guide is wrote by me, a simple user that is sharing his own experience of the last 4 and a half months with the device. Some statements may be wrong. I'll appreciate any positive recommendations in order to improve the guide and help the rest of the community to achieve the best battery life the device can give us.
I'm using actually Liquidsmooth v1.25 and PopcornKernel, in a GSM GNex with standrad battery (1700mAh), and I'm getting this results:
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
SCREEN
Due to the big screen, this is one of the elements of the device that affects in a major way to the battery live. (Great Savings)
It has been checked that black themes have a great impact on the battery due to the fact that one black pixel does not consume any battery.
Some apps have a black theme option on them, if you choose it you will save some battery.
On the other hand the brightness is the other part in the screen that has a big impact on the battery. In a logic way, less the brightness more the battery life. (Greatest Savings)
Now the latest ROM's have a new amazing feature, we can change the interval the sensor works to achieve the ambient light, reduce the brightness minimum value (that's by defect way too high in low light conditions), and customize your prefered light levels (that are too way too high in default configuration).
By reducing the sample interval sensor a bit and reducing the minimum value a lot we can achieved abetter battery life in a great manner.
Also adjusting the light sensor levels to a more reliable one's that are by far lower than the default one's we'll achieved a more optimize system that consumes less battery.
Note: This are my actual, after 2 weeks of adjust, values but I'm still working on them, they are no 100% reliable.
CPU
The CPU is a great beast. In terms of battery is well adjusted, by as always, we can achieve a personal optimized system (this is Android, yeah!) that will balance performance and battery life. (Great Savings Underclock and Undervolt combo).
A very good speed and fluidness can be achieved with a very good optimized and well balanced performance-battery friendly system.. and yes, with the last advances in kernels and ROMs, we can have a perfectly smooth system with a top speed of 1000Mhz.
In the other hand Undervolt will help us to achieve a cooler system with some battery gain. With Undervolt we´ll limit the max. value of the Voltage for the specified frequency, if we have a kernel with Smartflex, this one we´ll allow lower voltages depending on the power need of the CPU.
Two important things:
1. It has been tested that the 700Mhz frequency is prefereable over the 300Mhz one, due to the drops on frequency signal of the phone.
2. Undervolt values are not the same for everyone, it can oscillate depending on the individual CPU. When I UV I always test my system with an Stability Test app.
Connections
GNex is a phone...also.. well, it's a super computer with phone capabilities. Due to the "always connected" philosophy the optimal baseband will save a lot of battery. An optimal Baseband and Radio (region optimized) will require less power and time to connect to the antennas and will have better connection always (less power irradiated). (Medium savings).
The Radio should be updated and region optimized, there's a magnificent post made by josteink that explains all the details concerning the Radios with links to every one available.(GSM)
[Radio] (GSM) Galaxy Nexus I9250 Baseband dumps collection & discussion
European Radio Recommended: XXKK6 (XXLA2 is giving too high "Phone Idle", resulting in drain problems)
For the CDMA version there is another magnificent post by ready5 with a compilation of every RADIO for the CDMA version of the GNex.
(CDMA) [RADIOS/HYBRIDS]*UPDATED* 4.0.4 FULL 2/6/2012 PLUS FRIED RADIO Halp!
In the GSM version on the other part the 3G, HSPDA consumes great great great battery juice. If you are not in WIFI and are not using the data connection, a great way to save battery life is changing from HSPDA or 3G to 2G networks (this is really noticeable if you travel a lot by car or train, cause you are continuing connecting a reconnecting from different radio antennas).
There's some ROMs as Liquidsmooth that allows when you are not on WIFI and after an specified delay, to change to 2G automatically (or low consuming) networks when you have the screen off. This is a great way to save battery when you are not at home, reducing the standby drain of the phone outdoors.
.
The automatic 2G when sleep is a main function of Juice defender. Thanks to a1exus for recommendation.
In the CDMA version the LTE consumes also great great great battery juice. If you are not in WIFI and are not using the data connection, a great way to save battery life is changing from LTE to 4G networks (this is really noticeable if you travel a lot by car or train, cause you are continuing connecting a reconnecting from different radio antennas).
Thanks to thenickisme for this!
WIFI
Wifi has a crazy history on the GNex. After talking and talking, posting and posting, it has been tested that WIFI always on while sleep is the best way to achieve a longer battery life. (Medium savings).
Also the new ROM's have amazing feature that change the WIFI interval (we normally stay at the same WIFI always), increasing the value will save batterty life reducing the continues scans that produce the WIFI Always ON requirement.
Services and Apps
The best thing of Android is that we can configure anything, one of the best and underestimated feature is the Freeze or Service Uninstall. We did it before in Windows and we can do it now. Through the Apps section in Preferences or the mythic Titanium Backup we can disable or uninstall an internal function of the systems that is normally used, giving more resources to the system and in some cases, saving some battery. (Low to Minimum Savings).
There are some ICS functions that no everyone uses. For example, I don't use any Bluetooth, NFC, Google Voice, Google Search or Speech function of the system, freezing or uninstalling them will optimize our system giving some battery juice.
Note: This is a dangerous thing if you don't understand what you're doing. Make always a Nandroid before Freezing or Uninstalling an essential function, just to be cautious.
According to the Apps we have to take in account the Background Syncing or Sync Interval, most of the time the apps don't need to be synced every 5 minutes, like weather, if we make longer updates we'll achieve a good saving battery related. (Great Savings if many apps with many connections).
Widgets, 5 homescreens full of widgets updating in real time could be detrimental to the battery live, take care when adding widgets and as said in the previous paragraph, change every widget preferences to update in longer times than usually they have by default. (Great Savings if many apps with many connections).
Bad Apps are the one's that not allow our device to deep sleep or wake up continuously our GNex. There are several on the market, Readability for example is a new one that wake up continuously our device attempting to download new articles, on the other part, some time ago Widgetlocker had some problems not letting deep sleep the GNexus (don't know now). (Great Savings if there is an apps giving deep sleep or wake ups problems).
Pointing on this, the best way to know if any app is not behaving well in the system is through 2 apps:
- BetterBatteryStats, that will look for any wake up of the device while sleep.
- CPU Spy, that will tell us if the device is deep sleeping ok or not.
Other things
There are other things that will help us in a great or minor manner to save battery life.
Sync Data usage (Google services like contacts, bookmarks, etc..) consumes battery, if you limit this usage, you´ll gain some juice. The new ROM's in the Powersaver tag will allow you to limit this sync usage. (Low Savings).
The Dial Pad Touch Tones and Vibration affects battery also (yepp it's true, and in a great way!), disabling this features will give you some extra battery juice. (Low to Medium Savings with combo sound plus vibration).
The Google Location services and Backup&Reset Data consumes great battery also, limiting this services will gave you some extra juice. (Medium Savings).
The last little thing that will help you save batt life will be the Automatic Date&Time option, disabling it will give you some extra juice also. (Lowest Savings, practical minimum).
Live Wallpapers, they are very nice but will drain your battery quickly. Static Wallpapers are preferred, and if posible, dark ones. (Medium to Great Savings).
Experimental
This are new tweaks that normally appear in new/advanced kernels, his use according to battery save is still not really tested or can have a detrimental on the physical conditions of the device/battery. Use them with caution or if you really know what you are doing.
[MOD][KERNEL]Battery Life eXtender (BLX), this is a tweak created by the popular Ezekeel and in his owns words: "Older types of rechargable batteries exhibited a 'memory effect' which made it neccessary to completely charge/discharge the battery when using to prevent degradation of the capacity. Modern Lithium-Ion batteries like in the Nexus S do not show this problem and thus it is not necessary to use the battery in complete (dis)charge cycles. In fact on the contrary, it is commonly accepted that both very low and very high charge states accelerate the degradation of the battery capacity (that is why you should store Li-Ion batteries at around 40% charge).
While a low charge state can be simply avoided by charging the device more often, the battery in the Nexus S by default is charged to around 95% capacity and I could not find any app or tweak to stop the charging at a lower capacity. Thus the only way was to use the manual override and pull the cable which is annoying since one had to monitor the charge state." (Unknown Savings).
Galaxy Nexus is charged by default to the 96% of this capacity, with this new tweak you can gain this 4% (don't know for sure if you can get the 101%) of battery life, in 4 hours screen time, more or less 10 minutes, but it can be detrimental on the long way to the battery physical life.
You can found this tweak in the last nightly of Franco's Kernel, and can be activated via his own app.
You can find more information in Ezekeel post here at XDA.
[MOD][KERNEL]Undervolt of IVA and CORE Voltage, new patches let undervolt the IVA (hardware media decoder) and CORE (GPU Voltage), I'vce been playing with this all the day and I've managed to undervolt a 15-20% de original frequencies. (Unknown Savings).
I understand that with this we are limiting the maximum voltage they can use, letting them to use lower ones according to GPU load. I'm not sure at this (GPU uses smartflex also ¿?) but with a descent of 20% on the voltage could result in longer battery life while playing games or seeing movies.
I'll try further undervolts, but this are my actuals on a stable system.
You can play with this voltages via the last nightly of Franco's Kernel, and via his own app.
Take care playing with this, could result in system instabilities, reboots, freezes, etc.
Links of interest
- BetterBatteryStats, A high battery drain is often a limiting factor for a great user experience.
With BetterBatteryStats you can analyse the behavior of your phone, find applications causing the phone to drain battery while it is supposed to be asleep and measure the effect of corrective action.
- CPU Spy, This is a simple app to display the time the CPU spends in each frequency state. This can be a useful tool in diagnosing battery problems or tweaking your over-clock settings.
It also displays the current kernel information.
- StabilityTest, StabilityTest is a stress-testing tool for android devices with error reporting.
StabilityTest is a CPU, GPU, RAM/memory stress-testing tool for your device, whether stock and unrooted (limited functionality) or rooted and overclocked with SetCPU, SetVsel or similar tools.
Extended Battery
At the end, the best way to extend the battery life is with an Extended Battery, they are not very expensive and only increase a little bit the thickness of the device. They can be bought at several places through the typical places as Ebay, Expansys or Amazon.
Important: Take in account that the CDMA and GSM versions have different batteries and they are not compatible, normally the GSM one is longer and black and the CDMA is wider and blue.
Borrowed from Buddy Revell
Calibration
Once a month we´ll have to calibrate our battery so that the information to be shown on screen is accurate and true. The steps are as follows.
1. Charge the Nexus until the indicator shows us is 100%.
2. Disconnect it and let it discharge until it turns off by herself.
3. Then load up fully charged. Note that this state is reached after one hour approx. since it shows that is already loaded.
Note: There are several apps in the Market that help calibrate the battery, although I have heard that in ICS Google has changed the file location does. Log of our battery so many of them may not work well if they are not updated.
great post especially for a new gnex user. will look through these options thoroughly.
Very nice. Thank you! Took a few suggestions.
Looks like I've got some work to do =D
Sent from my Galaxy Nexus using XDA
edited out
Cool story bro! Lots of good tweaks to maximize battery.
Sent from my Galaxy Nexus using xda premium
What rom is that? You should state that ...
Awesome. Those custom backlight levels are going to save a good amount of battery. I tried using a filter, but it made using the phone in sunlight impossible.
It's working inside well and based on what I see from the custom levels, it should have no issues once I take it outside.
As for the underclocking, comparing iOS and Android isn't fair. iOS has an advantage with its closed ecosystem. I personally overclock the GNex to achieve the same snappiness I had on my iPhone 4S. Sure the underclocking will save battery, but I might as well be using an older phone if I'm going to underclock.
When it comes down to it, everyone's battery is >50% screen consumption. Your custom levels are going to tremendously increase battery life.
gogol said:
What rom is that? You should state that ...
Click to expand...
Click to collapse
It's in my signature, Liquidsmooth v1.25.
myrdog said:
Awesome. Those custom backlight levels are going to save a good amount of battery. I tried using a filter, but it made using the phone in sunlight impossible.
It's working inside well and based on what I see from the custom levels, it should have no issues once I take it outside.
As for the underclocking, comparing iOS and Android isn't fair. iOS has an advantage with its closed ecosystem. I personally overclock the GNex to achieve the same snappiness I had on my iPhone 4S. Sure the underclocking will save battery, but I might as well be using an older phone if I'm going to underclock.
When it comes down to it, everyone's battery is >50% screen consumption. Your custom levels are going to tremendously increase battery life.
Click to expand...
Click to collapse
Thanks
With the iPhone comparison I just tried to emphasize that sometimes underclocking results in the same snappiest system, but yes, is a little unfair though (but I can assure that with the latest Kernels and ROMs that have been released, I have a totally fast and smooth system with only 1000Mhz).
Well done good job
Good guide. Rather than seeing multiple thread's about awful battery life its nice to see people talk about how to maximize their battery life
Sent from my Galaxy Nexus using xda premium
Good guide—thanks for taking the time to make it—but along with it’s very good parts, it has quite a few inaccuracies, is misleading in some places, doesn’t fully explain the ramification of making many of the changes that are proposed and makes questionable changes for very little gain. Amongst other things, my major issues with it are:
You wrongly assume a device that does not get four hours of screen time is not optimized—this would be incorrect as one can get four hours of screen time with the stock ROM and default configuration.
The stock ROM does not allow you to customize the backlight and CPU—so you should point this out.
It’s condescending to the iPhone (while the GN might be better in many ways, patronizing another device has no place in a “guide”).
BinkXDA said:
Good guide—thanks for taking the time to make it—but along with it’s very good parts, it has quite a few inaccuracies, is misleading in some places, doesn’t fully explain the ramification of making many of the changes that are proposed and makes questionable changes for very little gain. Amongst other things, my major issues with it are:
You wrongly assume a device that does not get four hours of screen time is not optimized—this would be incorrect as one can get four hours of screen time with the stock ROM and default configuration.
The stock ROM does not allow you to customize the backlight and CPU—so you should point this out.
It’s condescending to the iPhone (while the GN might be better in many ways, patronizing another device has no place in a “guide”).
Click to expand...
Click to collapse
Thanks, but the guide tried to be a compilation of many procedures that would give you a longer batt life. Some of the recommendations give you maybe 4-5% more autonomy, some of them 0,5%, don't know because I'm not an engineer and don't have the tools and time to measure the actual rate of discharge of the device, I'm only a user that took some time in share his personal experience in the last 4 and a half months with the device.
1. It was a way of talking, did not tried to assume anything because was not thinking in anithing out of the people that are not having more that 3 hours batt time, was a simple way of selling something (a well/bad introduction depending on the eyes or mentality of the reader)
2. We are at XDA and this is a developer device, I asume a minimal technological base, I was assuming this. But I point this out because I also think that will help some people.
3. Tried to emphasize that while the over sold as an ultra-quick device is only 1Ghz Dual-Core, the GNex can be as fast and reliable as the iPhone 4S with the same speed, and also saving batt (and in addition you have 450 more Megaherzs if you want to use them.. if you root). It’s not condescending cause if I would have liked to buy an iPhone I would bought one as the 99% of the people here.
I am a simple user, as everyone here, trying to help people as people has helped me developing great ROMs and Kernels I like positive and concrete recommendations over vague and negative ones.
hey op,
SrTapir said:
If we take in account that the Mega-Ultra-Cool-Fashion-Posh and "Ultra Quick" iPhone 4S has a only Dual Core 1Ghz processor, we can assume that with the same speed we can achieved a very good optimized and well balanced performance-battery friendly system.. and yes, with the last advances in kernels and ROMs, we can have a perfectly smooth system with a top speed of 1000Mhz.
Click to expand...
Click to collapse
i think the iphone is clocked at 800mhz even it has 1ghz
king23adrianc said:
hey op,
i think the iphone is clocked at 800mhz even it has 1ghz
Click to expand...
Click to collapse
Ups!
SrTapir said:
Ups!
Click to expand...
Click to collapse
First of all thanks to all the people for your comments!
I've updated the first post with your recommendations, and added a couple little things.
SrTapir said:
First of all thanks to all the people for your comments!
I've updated the first post with your recommendations, and added a couple little things.
Click to expand...
Click to collapse
The Calibration section is a little confusing. It only takes 1 hour to go from 0% to 100%?
Also, do you know anything about calibration with ROMs that only allow you to charge to 99%?
myrdog said:
The Calibration section is a little confusing. It only takes 1 hour to go from 0% to 100%?
Also, do you know anything about calibration with ROMs that only allow you to charge to 99%?
Click to expand...
Click to collapse
No, it takes 1 hour after the GNex indicates is fully charged. I'll try to change it in order to clarify.
No, sorry, maybe you can "delete battery logs" via recovery. (I never did it, and don't know if can be detrimental).

NFC vs Tasker

I am aware I can combine both, but since I am new to NFC I would ask the question, which is as follows:
Which is better for battery life Tasker on all the time or NFC on all the time?
Right now I have the NFC component on and Tasker running 24/7 and I never saw any of them in the battery report. So they're using insignificant amounts of energy.
Personally I thing that if you're not patching your phone to read NFC tags with screen off, NFC is closer to being useless. It will take you about the same amount of time to reach for a shortcut on your screen.
Use NFC Task Launcher and Tasker together. Makes an amazing combo!

[Q] excessive battery consumption

Hello guys,
a few days ago I bought the notes 8.0 wifi and after a few hours they already had administrator permissions.
I left the tablet that becomes exhausted and completely after a night in office, in the morning I started to make some changes: new rom and kernel immediately immediately!
I state that in Italy are the CEO of an interesting blog where we treat only Google Experience products novel that I'm not really, but ...
Turning now from the Nexus 7 (I still have it) the difference for the better I feel about this tablet but I have noticed, however, an excessive drain on the battery, then not doing anything so important: the hours of active screen only 3/4 albeit with wifi always on!
I tried to set all the Governor also present with heavy undervolt but I have not noticed noteworthy improvements ...
nb. Rom and kernel belong to @civato
Tell me your experience, thanks guys
I didn't understand all of your post, but wanted to share my experience:
Leaving the screen brightness on auto is essential to get reasonable battery life. On full brightness my tablet battery runs out way too fast. I do think this device has the shortest battery life of 7 other tablet/phone devices I have previously used for multiple full days (I cannot judge with less usage). But as long as you leave it on auto brightness most of the time, it has managed to get me through each business day since it was released.
Sent from my GT-N5110 using xda app-developers app
reply
thanks for your expertise ...
you are absolutely right but also the tablet in standby consumes a small percentage of the battery, that's not good, at least to me.
I'll talk with the developers for the right settings in the kernel ... hopefully
I found that I only use a few percent when its in stand by. Heres what I have my settings as and why
Brightness - either auto +5 or 50% switching between the 2 as required.
Sync off.
Power saving mode - on unless I want to play resource heavy games.
GPS off. only turn it on if an app specifically requires it (navfree)
Bluetooth off.
spen battery saving mode on. the spen layer uses charge so no point having it on unless i need it. if im using my 8pi pen i just leave the spen out a little, using it like a switch.
Other battery saving things.
Auto airplane mode - app that turns all the signals off when the screen is off.
trickster mod - under volted by 75 on the CPU accross the board (had a few crashes on 100). also undervolted the GPU and changed the ramping threasholds.
- govner set to lulzactiveq which is a modified interactive but also with the benefit of limiting the cpu when the screen is off.
- set ignore_nice_load to 1. so that nice to have processes are now no longer run. only the higher priority ones are.
greenify - set various apps to hibernate stopping them from taking the tablet out of sleep.
Think thats everything.
The primary settings you listed @hertsjoatmon, are standard on Android (and better on Samsung devices) say: I will use them for years.
The second part is more interesting, in fact undervolt to -75 they had not yet tested on this note 8 but if you tell me that the tension holds well-being.
Also on the GPU did you apply the undervolt?? mmmm
The Governor me most is satisfying, at least in terms of battery life - albeit with some lag micro - is "ondemand" (100 -> 1200) with frequency freeze (of 4 cores), thanks to kernel @civato :good:
Standby does not consume almost nothing but if you use the goodness of the screen, wifi and all notifications accesse lead to excessive battery consumption that even my Nexus 4 behaves this way (having then 2100m)
Piè_Nexus said:
The primary settings you listed @hertsjoatmon, are standard on Android (and better on Samsung devices) say: I will use them for years.
The second part is more interesting, in fact undervolt to -75 they had not yet tested on this note 8 but if you tell me that the tension holds well-being.
Also on the GPU did you apply the undervolt?? mmmm
The Governor me most is satisfying, at least in terms of battery life - albeit with some lag micro - is "ondemand" (100 -> 1200) with frequency freeze (of 4 cores), thanks to kernel @civato :good:
Standby does not consume almost nothing but if you use the goodness of the screen, wifi and all notifications accesse lead to excessive battery consumption that even my Nexus 4 behaves this way (having then 2100m)
Click to expand...
Click to collapse
my clock and voltage settings are discussed here... http://forum.xda-developers.com/showthread.php?t=2319953
I've not really updated any of my threads since coming back from holiday. I will do at some point but im pretty happy with my set up at the moment and have only been lurking on here rather than actively contributing these last few weeks.
the situation seems to have improved a bit, with cuts of volts everywhere: P
let's see if over time more kernels will do miracles ...

NFC Field Strength

Hi all,
I have developed a circuit board which is powered purely on the magnetic field generated by my phones NFC antenna. Using this method I am storing the energy from the magnetic field in a capacitor and I am able to achieve up to 3.3V. However I have found that when active the NFC in my phone generally only chargers the circuit after it has first detected it as a tag. From what i can tell the field strength is very weak when polling for a tag and is only strong for a short time after it detects a tag and is in the process of reading the tag. Is this a correct analysis of how the NFC behaves in android phones (i assume this is to conserve power when polling g for tags) and is there a way to hack the phone to always have the feild strength operating at max capacity?
My understanding of the NFC behavior is based on experimenting with the my NFC phone and circuit board. I find after the phone has detected the circuit board as a tag the voltage across my circuit will increase fro about 1 second and stop increasing even though its in the same position. Then moving the board away and placing in the field again charges the voltage up further, reporting this several time eventually gets the voltage to 3.3V.
For my application the phone is only active as an NFC reader for a product, as such the battery consumption and effect on other features of the phone is irrelevant.

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