3G vs wifi: battery life?

[Mahalo]

For those who asked, here is some good info regarding WiFi v 3g.

This first link is an excellent technical paper on Cellular Power Management and is in pdf format:

http://www.cs.umass.edu/~arun/papers/TailEnder.pdf

For the second (Far less technical) you will need Open Office or Powerpoint (or PPT viewer) to see it. Contrary to the title, it is not all about YouTube.

http://www.ece.udel.edu/~bohacek/SensorAndDataWirelessNets_2010/Energy/3GvsWiFIWithYouTube.ppt

WiFi is CLEARLY proven to be more power efficient.

 

[jayjay1122]

I'm not really sure what you mean. When I was in my apartment all day yesterday, I turned off 3G, turned on wifi, and connected to my wireless network. Wifi has definitely not kept my phone awake (40 hours up, 4 hours awake). What "stock setting for wifi usage" are you talking about? I just have it on. I don't see anything about it turning off after 15 minutes. Could you tell me specifically how I get to these settings?

Settings -> Wireless&Networks -> Wi-Fi Settings -> Menu -> Advanced
There you will see the WiFi Sleep Policy and the default setting is Never.

 

[Dream]

I always get much better battery life when connected to wi-fi. Hands down.

 

[Rdjr74]

there is a setting for 3g it's called "always on" which means it will turn off while the phone is alseep, saves a ton of battery for me.

Then answer me this. I was at my parents house out in the country were there is very limited tower signal. To get 3G I would have to go outside and keep my fingers crossed and hope to get a 3G signal. Aware of this, I fully charged my battery, went to bed at around 11pm and was waken up to a phone that had less then 15% battery life. So, if the phone sleeps after a certain period and turns off 3G as you stated above, then why did my phone drain so fast? Just looking for answers....

Thanks

 

[ChiTownJim]

Then answer me this. I was at my parents house out in the country were there is very limited tower signal. To get 3G I would have to go outside and keep my fingers crossed and hope to get a 3G signal. Aware of this, I fully charged my battery, went to bed at around 11pm and was waken up to a phone that had less then 15% battery life. So, if the phone sleeps after a certain period and turns off 3G as you stated above, then why did my phone drain so fast? Just looking for answers....

Thanks

Your phone was constantly looking for 3g signal or going in and out of signal area . I stayed with my parents for a couple days and slept in there basement where there is very little service and my phone would drain half the battery in 6hrs of sleep trying to keep a signal . It won't just turn of 3g when the screen is off that would defeat the purpose of a smartphone as you would not get any email notification or any data of any sort with 3g off and no wifi .

 

[bweave]

ChiTownJim - regarding your use of tasker. Can you detail more what you have Tasker do and HOW you do that?

I have been trying to do something similar but have not had the time to devote to learning Tasker.

Thanks.

 

[ChiTownJim]

ChiTownJim - regarding your use of tasker. Can you detail more what you have Tasker do and HOW you do that?

I have been trying to do something similar but have not had the time to devote to learning Tasker.

Thanks.

I gave up on learning all tasker could do about a week after I installed it but I did manage to create a profile that turns wifi off when there isn't one of my "perfered" wifi networks in range . It's the easiest thing to set up tasker to do . But honestly not worth the price of the program unless you're going to learn all its features I just didn't have the time or patience to work with it .


Ohh and a thing about how little power wifi uses is this ... I have a rooted droid eris as a backup phone but I leave it on and connected to wifi and carry it with me . I have it synced to all the same stuff as my incredible so if I'm on the phone and need to check my calender I use my Eris I also use it as my secondary alarm . Now it has no phone service what so ever and with the stock 1300 mah battery it will last 10-14 days . It's a great tool to have to accompany my phone. Main reason I haven't sold it , it's worth more to me then I could sell it for

 

[txrxio]

it's called "always on" which means it will turn off

I thought of so many witty lines about this sentence fragment, but none of them do justice to it.

 

[Rdjr74]

Your phone was constantly looking for 3g signal or going in and out of signal area . I stayed with my parents for a couple days and slept in there basement where there is very little service and my phone would drain half the battery in 6hrs of sleep trying to keep a signal . It won't just turn of 3g when the screen is off that would defeat the purpose of a smartphone as you would not get any email notification or any data of any sort with 3g off and no wifi .

I'm aware of that but I was looking for a response from the other dude I was quoting. According to his quote it shouldn't have been constant looking for a 3G signal if it was asleep, unless it needs a 3G signal first to fall asleep which really doesn't make much sense. Kind of like reading a bedtime story to a baby. Should I read to my phone so it can fall asleep. Just looking for some clarification from his quote, that's all.

 

[euph_22]

For anybody who's seeing alot of battery drain overnight while on wifi, you could try changing the wifi sleep policy. It's buried in the wifi settings page in the menu. Go to the Wifi Settings, hit menu->advanced.

I'm not promising anything, but it's something that might help. In sleep, it'll be less battery intensive to use a good 3G signal than a poor wifi (probably). (NOTE: if you unselect both Mobile Data Always on and Wifi always on, you will completely lose data connectivity after your phone is asleep for 15-20 minutes. Really more of an issue with the Mobile Data (since you don't always have wifi), but something to keep in mind).

Your mileage may vary...obviously, if you have great wifi versus crap 3G, this will actually hurt your battery life.

 

[euph_22]

Then answer me this. I was at my parents house out in the country were there is very limited tower signal. To get 3G I would have to go outside and keep my fingers crossed and hope to get a 3G signal. Aware of this, I fully charged my battery, went to bed at around 11pm and was waken up to a phone that had less then 15% battery life. So, if the phone sleeps after a certain period and turns off 3G as you stated above, then why did my phone drain so fast? Just looking for answers....

Thanks

There are a few possibilities. First off, the basics. Did you turn off Mobile Data always on? Because if you didn't than your 3G signal WON'T sleep. It will stay connected, which will burn through battery in horrible signal areas. The default setting is ON (that is Mobile Data Always On is selected).

Secondly, if your phone never actually reachs that level of sleep, it won't turn off the 3G. Let's say that the phone needs to be at the lowest level of activity for 20 before the 3G turns off. If something brings the phone (or keeps the phone) at a slightly higher level of awakeness, it would prevent the phone from turning off 3G.

Third, do you have something that's keeping the phone from sleeping at all? If you usually don't see massive drain overnight, that's PROBABLY not the case, but I want to cover all bases.

 

[1967ls2]

When I'm at work I connect to the wifi here, when I go home I connect to the wifi there.
I have tested it by leaving the 3G connection on when I am at those two places (work for 8 hours a day, then home for the rest of the day) and I feel very strongly that I get far superior battery life when I deactivate my 3G and stay connected to wifi ONLY.
When I am connected to wifi and leave my 3G connected also my battery drains at a quicker rate.
When only connected to wifi and 3G turned off, I can normally get about 7.5 hours of awake time, meaning actual use of the phone.
When connected to wife with the 3G turned on this time decreases by about an hour or more.
These are just my findings and thought I would share. I have the 3G toggle switch on my main screen and just toggle it on & off when I get to work and home.

 

[Rdjr74]

There are a few possibilities. First off, the basics. Did you turn off Mobile Data always on?
NO
Because if you didn't than your 3G signal WON'T sleep. It will stay connected, which will burn through battery in horrible signal areas. The default setting is ON (that is Mobile Data Always On is selected).
Secondly, if your phone never actually reachs that level of sleep, it won't turn off the 3G. Let's say that the phone needs to be at the lowest level of activity for 20 before the 3G turns off. If something brings the phone (or keeps the phone) at a slightly higher level of awakeness, it would prevent the phone from turning off 3G.

Third, do you have something that's keeping the phone from sleeping at all?
Definitely Not
If you usually don't see massive drain overnight, that's PROBABLY not the case, but I want to cover all bases.

-Thanks for the info. I actually never messed with any of these settings, amazingly! So do you recommend turning off the enable always on mobile networks?

-Also in that menu, should I keep the data roaming checked? I am assuming no because if you're roaming then typically aren't you in a lower signal area thus no 3G signal?

 

[euph_22]

-Thanks for the info. I actually never messed with any of these settings, amazingly! So do you recommend turning off the enable always on mobile networks?

-Also in that menu, should I keep the data roaming checked? I am assuming no because if you're roaming then typically aren't you in a lower signal area thus no 3G signal?

If you're having high drain in standby I'd deselect the always on option. You won't get email/etc then, but it's not a big deal waking the phone up to let it check that. When you're asleep you really don't need it updating stuff. (i kept mine on, but I'm usually in good signal areas).

The only reason to uncheck roaming is to avoid roaming charges. Unless you live right next to an international border, that's A nonissue

 

[jayochs]

did my own WIFI test yesterday, and just as i suspected, i definitely do NOT get better life with WIFI.

same use as usual, turned my wifi sleep policy from ALWAYS ON to 15 min, and i still had around 65% awake time in 9 hours, which is A LOT for my phone.

after 9 hours, it was at around 15% left.....usually i get to 15% left at around 15 hours with the same usage and wifi off. therefore, for me anyway, wifi drains battery more than it saves it.

to note, i always have full strength wifi connection, and my 3g is around 88 dbms in here.

 

[Markus729]

I use Y5 to turn on WiFi whenever possible, (at home, work) and wherever you go that has wifi. It remembers the location and turns off 3G and switches to Wifi. Pretty nice app, and I have very good battery life.

 

[octoberdana]

I did download Y5 and notice that it will come up and ask me if I want to switch to available wifi networks. I like that at home, it switches to wifi automatically. My only dislike is that if I move outside of a wifi area I have to manually turn on mobile data and sometimes I forget to turn it back off.

 

[falltime]

There is a simple answer to this - you get better battery life when on Wifi then when on 3g. Any results to the contrary are = user testing failure

 

[ChiTownJim]

There is a simple answer to this - you get better battery life when on Wifi then when on 3g. Any results to the contrary are = user testing failure

This is the best put answer period

 

[howarmat]

ok so for everyone who says wifi uses less, please explain this to me...androids stock setting for wifi usage is to never let the phone sleep. meaning, if none of you changed the setting, you all have 100% awake time. if you changed the setting to turn off after 15 minutes, then after fifteen minutes your 3y radio turns back on and wifi turns off until you wake the phone up again. from what i've come to learn, 100% awake time=bad on the battery life...so what is all yours set to? 15 min or never turn off?

No this is not correct. You phone can be connected to wifi for 100% of the time and yet still sleep, that is not the same thing at all.

see here, phone is not on 100% of the time even though wifi is

did my own WIFI test yesterday, and just as i suspected, i definitely do NOT get better life with WIFI.

same use as usual, turned my wifi sleep policy from ALWAYS ON to 15 min, and i still had around 65% awake time in 9 hours, which is A LOT for my phone.

after 9 hours, it was at around 15% left.....usually i get to 15% left at around 15 hours with the same usage and wifi off. therefore, for me anyway, wifi drains battery more than it saves it.

to note, i always have full strength wifi connection, and my 3g is around 88 dbms in here.

this is why your test failed probably. You were switching from 3g to wifi all the time. Thus using power to swap the radios constantly and its also using the 3G network for the majority of the time.

If you are having awake issues its NOT because of the wifi. Its something else like an app or whatever

 

[howarmat]

I use Y5 to turn on WiFi whenever possible, (at home, work) and wherever you go that has wifi. It remembers the location and turns off 3G and switches to Wifi. Pretty nice app, and I have very good battery life.

i have been using this from day 1 pretty much and had teh same type of app on my BB. It is a great app and its free!

I did download Y5 and notice that it will come up and ask me if I want to switch to available wifi networks. I like that at home, it switches to wifi automatically. My only dislike is that if I move outside of a wifi area I have to manually turn on mobile data and sometimes I forget to turn it back off.

you are doing it wrong. The wifi comes on, 3G will automatically turn off. You leave the wifi area and the 3G should come right back on automatically. you do not have to do anything with the data connections at all. the app does it all for you.

 

[howarmat]

all of this comes down to how good your wifi signal is and how good your 3G is. If either is not a good connection it will not be good for the battery no matter what. Also your security settings and such CAN cause bad drain with wifi even. but the fact is the wifi radio will use less power than the 3G radio give the signal is good. thus you should have much better battery. my advice is use wifi as much as you can at home or work, as long as the settings are correct your battery life should be better than the 3G network unless you are standing next to the damn tower

 

[jayochs]

No this is not correct. You phone can be connected to wifi for 100% of the time and yet still sleep, that is not the same thing at all.

see here, phone is not on 100% of the time even though wifi is

this is why your test failed probably. You were switching from 3g to wifi all the time. Thus using power to swap the radios constantly and its also using the 3G network for the majority of the time.

If you are having awake issues its NOT because of the wifi. Its something else like an app or whatever

i appreciate the non-smug attitude in response to my reply, however i've got to tell you that your phone is clearly not the same as mine. when i set it to wifi always on, i get 100% awake time. when i turn wifi off, during the next reboot i'll get my normal 20-30% awake time. no task killer, no different apps running. please explain why this would occur?

to summarize, for me with wifi on ALWAYS ON, my phone WILL NOT sleep. it will remain at anywhere from 70-80-100% awake time.

 

[appleaj]

So for those of you who don't understand why Wi-Fi uses less battery than using only 3G, hopefully this will help. Think of it this way, if you're on Wi-Fi your phone is connecting to something which is relatively close to you, therefore it doesn't have to do as much searching compared to looking for a cell phone tower which is typically hundreds of feet away, if not several miles. This is a general idea anyways. If there is no Wi-Fi available, it's a different story.

 

[euph_22]

If there is no Wi-Fi available, it's a different story.

Or if there is a marginal Wifi connection.