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Wifi - Battery life

Interesting observation, perhaps the coding Guru's can take into account. I noticed that at home where I seem to have perfect 4g signal, my battery lasts nearly 20+ hours and seems great.
My wife, who works at a hospital also noticed that at work she barely gets 6 hours and has to swap batteries constantly. Her phone also seems to always been warm and the battery info reports the same data that it always does(Blaming the screen). She's been complaining to me for a while, threatening to want to go back to the iphones and I've been trying to look for a solution.
So fast forward some time, I notice that when I go to an area with spotty service(an Office in Delaware that I occasionally visit), I'm lucky to get 6 hours of life on my phone. It also was exhibiting the same luke warming heating that my wife had been complaining about. I disabled data and got it to straggle by, but then I also experimented with wifi.
The wifi in that office is super strong and when I connected to wifi with my phone instead of having it constantly search for Edge/3G/LTE, it would just sit on wifi and never bother searching for signal.
This boosted the life from the 6 hours to 14 hours. I also recommended the same to my wife and she went from 6 hours to 18 hours(Better Wifi signal and no 4 hour train ride with spotty signal searching)
So, perhaps the radio logic is way too aggressive on these phones and if there was a way to make them just calm down and not look for 5 minutes if it doesn't find signal, perhaps they wouldn't burn themselves out.
Is there a way to reduce the radio aggressiveness? Cause quite frankly, if I don't have signal the second I walk out of the subway, I could really care less. Polling every 5 minutes is totally fine by me and it would be even better if it was configurable.
Anyways, perhaps others who are suffering with terrible battery life could experiment and see if enabling wifi extends their battery longetivity.
Cheers!

Er...I think everyone knows that WiFi increases your battery life substantially. However, user defined polling times might not be a bad idea.
Sent from my Droid Charge running Humble 1.4

I know wifi increases battery life, and and on the flipside if you don't have a strong wifi signal it will keep trying to find one... But my question is how much drain?
I drove to work in Queens from central new jersey (about an hour and a half and the battery drained about 60% with the wifi switched on. Is this the fault or do I have another problem?
Running latest humble fe
Sent from my SCH-I510 using XDA Premium App

I want to say that it drained purely because it was trying to find any signal, even if Wifi was off, I'd be willing to wager that it would have still lost that much battery life on the drive in.
All this still makes me think that if the devs could find the logic that controls the radio probing and allow it to be set based upon configurable options, our battery lives would be tremendously better.

superslow said:
I want to say that it drained purely because it was trying to find any signal, even if Wifi was off, I'd be willing to wager that it would have still lost that much battery life on the drive in.
All this still makes me think that if the devs could find the logic that controls the radio probing and allow it to be set based upon configurable options, our battery lives would be tremendously better.
Click to expand...
Click to collapse
So it is reasonable to assume the wifi search drained it that much? I I doubt it was general lte/data searching -new york is pretty covered
Sent from my SCH-I510 using XDA Premium App

[Q] Low Signal

I have a huge battery drain, and i think that is because i have low signal (look at the picture).
I tried to recalibrate battery for two times, and use it for 2-3 days, but it's alway the same.
I get maybe 7h with normal use. 50% of the time with 3G/EDGE, 50% with WIFI. screen time 1h, and turned off Auto sync.
Can someone help me? I need my phone whole day, not 7h. :S
EDIT: I'm using stock 4.0.4 with matr1x kernel

Bump?

Can't really help you as cell reception is based on the quality of the carrier. I normally experience -95 dBm and I believe it is a cause for such high drain too.
The only thing I could recommend is try flashing a different radio and see if you get a better signal?
Sent from my Nexus S using XDA

BetterBatteryStats can let you know if it's not the radio. To test if it is the radio, try switching to 2G only.

Well, it was 3G-s fault. I switched to 2G and now there is no battery drain.
BUT, i still don't know why is there no 3G network in my house.
I have SGSII on my shelf, with the same carrier and it has 3G.

There is 3G at your house. It is just weak, much like me. A few too many concrete walls where i'm at.
Cell signals are done through waves which have to penetrate through walls and other solid objects, this vastly weakens the signal. Once you hit the ~-100dB mark your phone will start throwing more power into it's antenna to compensate, much further and it ditches 3G and goes to 2G assuming it has better coverage. Around the 100dB mark it tends to stay with 3G if data is on though which can start chewing through battery. It would be able to play around with the parameters but i don't see this happening anytime soon.
Compare the dB reading on your SGS2 and Nexus S. If it's much worse on the Nexus S, try flashing a different radio.

I have the same problem, i just switch back to 2g when i get back home and at night. for some reason, 2g networks tend to always have stronger reception

Is there a way to conserve battery when you have weak signal?

I stay in a hotel room often without free wifi. Most of the rooms I get 1-2 bars, occasionally 3. A decent amount of the time I get no 4g and sometimes signal is so weak no internet at all. I notice this destroys my battery life. Is there someway to lower the extra strain on the battery when I know I will have a weak signal anyway without using airplane mode? I wanna lower the power being used by my phone to search for stronger signal while still being able to receive texts and calls. Would prefer to keep 3G on as well when it works.
On a related note, are there any products I can buy to boost my signal that work? And is there a rom or roms that are known to have great signal strength compared to the rest out right now? Thanks for any help.

sfetaz said:
I stay in a hotel room often without free wifi. Most of the rooms I get 1-2 bars, occasionally 3. A decent amount of the time I get no 4g and sometimes signal is so weak no internet at all. I notice this destroys my battery life. Is there someway to lower the extra strain on the battery when I know I will have a weak signal anyway without using airplane mode? I wanna lower the power being used by my phone to search for stronger signal while still being able to receive texts and calls. Would prefer to keep 3G on as well when it works.
On a related note, are there any products I can buy to boost my signal that work? And is there a rom or roms that are known to have great signal strength compared to the rest out right now? Thanks for any help.
Click to expand...
Click to collapse
You should be fine disabling Mobile Data... You should get texts just fine and use the WiFi for all data purposes.

Im not using the wifi ever unless really important to get it, $15 everyday is too much. So i am trying to rely on mobile data.

Go download the free app "Phone Info", it will allow you to shut off 4G, shutting off 4G stops it from searching and draining your battery.
Once installed, click "Device Information" and scroll about half way down and change the drop box from "LTE/CDMA/EvDo" to "CDMA only"
Hope this helps!

I use phone info already, 3g over 4g definitely helps, but am I wrong in assuming that the phone is still destroying battery when the signal is weak even with 4g off?

Battery Drain when no(low) signal

Hey guys,
I notice that my S3 battery is drained when I'm at work, when my network signal is limited. It only drains when I'm in the part of the building that has poor signal reception, or if I'm at a certain restaurant I frequent where reception is spotty. I assume it is because the phone is fighting to hang on to the little signal it has... but I'd prefer to keep my battery until I actually can use the phone.
Is there a way to help alleviate this without having to turn the network off? Like increase the amount of time between network scans?
I have root.
Thanks

Here you go, try these suggestions
http://forum.xda-developers.com/showthread.php?p=33104512
Sent from my white sgs3 running Eclipse 2.1

SOT - how to measure, is this reasonable?

Hello,
I recently picked up a OP6 and I'm really pleased with it overall but SOT has been a little disappointing. At least I think it has depending which battery app I consult!
Accubattery Pro thinks I'm getting an average 8h 16m of SOT (this is definitely not correct!).
GSM Battery Monitor PRO reckons 4h 46m of SOT (which still seems a bit high).
In the battery tab of the Settings menu it reckons having used 65% of my battery I've had 2h 50m SOT (ie. from 100% after 2hr 50m of SOT I'm now sitting on 35%). I think this equates to about 4h 30m of SOT if I continued at the same pace. I guess this tallies pretty closely to the GSM Battery Monitor PRO so maybe this is about accurate.
I've followed the guide here to get the most SOT but 4h 30m seems on the low given that I don't game or stream, don't have FB installed etc. This is purely webbrowsing, a bit of YT and a podcast app (listening to downloaded podcasts rather than streamed if that makes a difference).
Nothing in the battery stats seems that unusual (please see attached). What does seem a little odd is that I'm not in a great spot for mobile reception but looking at the stats it doesn't look like the radio is draining the battery.
Any advice on how to delve deeper? I'm 100% stock and not rooted.
Any advice for a OP newbie is much appreciated

Hmmmm Better Battery Stats seems to tell a rather different story especially around the radio reception.
Again any advice much appreciated!

The poor signal is killing you. When the signal is poor it pumps out more juice trying to stay connected. If you will be in an area with poor signal and won't be using your phone I suggest putting it in airplane mode or maybe setting it to 3G as a proof of concept. If your battery is much better then you found your issue

Also wifi scanning is turned on,which is a battery killer. Turn it off and you can see a great difference

spartan268 said:
The poor signal is killing you. When the signal is poor it pumps out more juice trying to stay connected. If you will be in an area with poor signal and won't be using your phone I suggest putting it in airplane mode or maybe setting it to 3G as a proof of concept. If your battery is much better then you found your issue
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Click to collapse
Thanks Spartan! The problem is poor indoor reception with the signal constantly cutting in and out. As such airplane mode may be the ultimate option but obviously it's a bit of a bummer as a long term solution! I'm going to try another provider which claims to have better indoor coverage in my area.
Question #1 - you mention trying setting to 3G as a proof of concept. Is that because a 2G/3G uses less power to connect than searching for a 4G connection? Should I try the 2G only option before the 3G one?
Question #2 - if I do try 2G/3G (before trying airplane mode) should I turn off mobile data too or does that make a difference?
Question #3 - I'm guessing having 2 sims installed makes the problem even worse as both are constantly calling for signal? I typically use one for data and one for voice.
Question #4 - when some folks post their battery graphs they have a picture which shows the mobile and wifi signal (see attached as an example). I don't seem to be able to find this. Was it removed from the latest update as the battery section seems to have changed a bit.
Thanks again!

hasan4791 said:
Also wifi scanning is turned on,which is a battery killer. Turn it off and you can see a great difference
Click to expand...
Click to collapse
Thanks for taking the time to reply!
Strangely I don't think I do have wifi scanning on (please see attached screenshots)! Location services are also off.
Are you thinking I do because the wifi is on 100% of the time?
Could this be because an app is somehow keeping it awake?
Hmmm can't see an option to check if "keep wifi on during sleep" is enabled. Has this been removed from 9.0.2?