Which is better for battery life? O have both good 3g and widow connection are work.
Will using wiring be better for battery or just 3g?
Sent from my SGH-T959 using Tapatalk
Yo.
3g = 3 - 5 MBits/s
WiFi = 10 - 120MBits/s
And yes we have WiFi N in our phone.
Do the math on how much longer 3g will last.
Sent from my GT-I9000M using XDA App
3G sucks down the most juice. It's just a fact. 2G will drain the battery less and if you have WiFi, your battery life will increase even more. I can leave my phone on overnight with WiFi on while sleeping and it will still have 80% when I wake up (5-6 hours)
Today was the first day I have ran wifi all day and I would say me battery use appears to be about the same as having 3g coverage all day. I would have figured wifi would drain more, but I haven't noticed a difference. Again this is just 1 day experimenting (I have my wifi set to never go to sleep with the screen off too). I have been connected to wifi 90% of the time. As a bonus wifi is a lot faster than the 3g speeds I get, so I think I'm going to leave wifi on all the time now.
Thanks for the opinions guys.
Sent from my SGH-T959 using Tapatalk
If I leave wifi on at night I lose about 8% or so in ~8hrs.
Sent from my SGH-T959 using XDA App
When I'm on wifi I normally turn all mobile data off. There's a widget that comes with Juice Defender that allows you to do that with one press. You can still get emails and texts, so the only thing you can't do is stuff that requires a cell connection, like Market. It really saves a ton of battery to turn off both 2G and 3G radios.
As others have said, Wifi is better for the battery. If you're connected for most of the day it'll also help to disable the Vibrant's wifi sleep policy.
Settings>Wireless and network>Wifi settings>Menu>Advanced>Wifi sleep policy>Never
vapotrini said:
As others have said, Wifi is better for the battery. If you're connected for most of the day it'll also help to disable the Vibrant's wifi sleep policy.
Settings>Wireless and network>Wifi settings>Menu>Advanced>Wifi sleep policy>Never
Click to expand...
Click to collapse
Stupid question but why? Wouldn't that eat battery? Or does it just male the phone stay on wifi rather than when it sleeps and comes back the wifi doesn't re-iniate?
Sent from my SGH-T959 using XDA App
fnakfhe said:
Yo.
3g = 3 - 5 MBits/s
WiFi = 10 - 120MBits/s
And yes we have WiFi N in our phone.
Do the math on how much longer 3g will last.
Sent from my GT-I9000M using XDA App
Click to expand...
Click to collapse
your logic is wrong.
3G actually uses more battery, so if you turn 3G off, wifi will save your battery.
Related
OK so I have read different way to save battery power on rooted nexus s but don't know what is best. I am currently using setcpu but can not tell a difference. If anyone has another way please share in great detail because I am new to rooted phones.
Sent from my Nexus S using XDA App
Turning off the mobile data connection will make an enormous difference you won't believe it.
Second is use WiFi when available, it will save tons of battery.
Why does there always have to be a funny guy.
Sent from my Nexus S using XDA App
He's not joking. That IS how you do it.
Sent from my Nexus S using XDA App
Man Im sorry dude read that wrong. I thought he said turn phone off LOL......
Sent from my Nexus S using XDA App
Not so sure about the wifi part. I've compared the phone idling on 3G vs. idling on wifi and with wifi there's definitely more power draw. Confirmed it with System Panel, the CPU is pegged at around 10% usage while idling with wifi vs. about 1% when idling on 3G.
This has been consistent with all my other android phones too (Nexus One, Vibrant, MT4G)
B3arfruit said:
OK so I have read different way to save battery power on rooted nexus s but don't know what is best. I am currently using setcpu but can not tell a difference. If anyone has another way please share in great detail because I am new to rooted phones.
Sent from my Nexus S using XDA App
Click to expand...
Click to collapse
can please post what your setcpu settings are? thx dude!
dinan said:
Not so sure about the wifi part. I've compared the phone idling on 3G vs. idling on wifi and with wifi there's definitely more power draw. Confirmed it with System Panel, the CPU is pegged at around 10% usage while idling with wifi vs. about 1% when idling on 3G.
This has been consistent with all my other android phones too (Nexus One, Vibrant, MT4G)
Click to expand...
Click to collapse
You're right, wifi uses more power than 3G, and they both use more power than 2G. When idling I'd definitely want to sit on 2G if anything. When you actually need an internet connection though, wifi and 3G will be more efficient. They'll use more power but will download much faster to make up for it.
Saving power is the same for almost all android devices:
1) turn off mobile network when not in use
2) turn off wifi when not in use
3) turn off gps
4) turn off automatic syns( if you dont use them)
5) brightness set to low
6) turn off live wallpapers
7) use a black wallpaper
8) turn off haptic feedbacks
9) set screen time out to a smaller interval.
all these steps might help you but it kind of takes away the charm of the phone imho.
dinan said:
Not so sure about the wifi part. I've compared the phone idling on 3G vs. idling on wifi and with wifi there's definitely more power draw. Confirmed it with System Panel, the CPU is pegged at around 10% usage while idling with wifi vs. about 1% when idling on 3G.
This has been consistent with all my other android phones too (Nexus One, Vibrant, MT4G)
Click to expand...
Click to collapse
It's definitely the opposite of that, its counter intuitive but WiFi uses significantly less battery life over 3g. I can post some numbers when I get home tonight if anyone's interested. But a good test is leave your phone on WiFi all night, then repeat on 3g and see the enormous difference. Better yet just look at the official Google specs, web browsing time is always higher on WiFi.
I did some real nice graphing of current draw at 2 second sample rate comparing various tasks which is What I'll try to post later..
What's the best rom for battery life?
Sent from my Nexus S using Tapatalk
robstunner said:
What's the best rom for battery life?
Sent from my Nexus S using Tapatalk
Click to expand...
Click to collapse
Bionix 1.2 @ stock speed, not the OC-ed version
it's stable, fast, and battery good
i have my data on all the time sync-ing every 30min
and 1 battery can last me a full day without plugging it in
Wifi automatically sleeps if your phone is idle for so long, therefore saving battery. 3g absolutely kills my battery so I have mobile data disabled when not using it. Works well for me. Also screen brightness on 0% using an app works good.
Sent from my Nexus S using XDA App
deeren said:
Saving power is the same for almost all android devices:
1) turn off mobile network when not in use
2) turn off wifi when not in use
3) turn off gps
4) turn off automatic syns( if you dont use them)
5) brightness set to low
6) turn off live wallpapers
7) use a black wallpaper
8) turn off haptic feedbacks
9) set screen time out to a smaller interval.
all these steps might help you but it kind of takes away the charm of the phone imho.
Click to expand...
Click to collapse
I agree!!!!!!
AllGamer said:
Bionix 1.2 @ stock speed, not the OC-ed version
it's stable, fast, and battery good
i have my data on all the time sync-ing every 30min
and 1 battery can last me a full day without plugging it in
Click to expand...
Click to collapse
Should you use setcpu with this rom? Or is it better without it
Sent from my Nexus S using XDA App
B3arfruit said:
Should you use setcpu with this rom? Or is it better without it
Sent from my Nexus S using XDA App
Click to expand...
Click to collapse
i tried with and without setCPU, and the difference in power saving was marginal
so i removed it.
it probably gave me an extra hour, but there is a bug with setCPU when picking up calls, it gets staticky until the CPU is at 800 Mhz or more
so with all that i mind, i decided to remove it
leerobson99 said:
Wifi automatically sleeps if your phone is idle for so long, therefore saving battery. 3g absolutely kills my battery so I have mobile data disabled when not using it. Works well for me. Also screen brightness on 0% using an app works good.
Sent from my Nexus S using XDA App
Click to expand...
Click to collapse
True, change the WiFi sleep policy to "never" to avoid this and extra battery savings.
I've been getting the best with CM7 so far, but I think all the roms that are about the same as long as you don't overclock them.
Use a black static wallpaper, low brightness, and get the black-themed MMS and Gmail apps from the Themes/Applications forum.
I can get well through my work day. Usually have 2+ hours of display time on and about 16 hours off the charger by the time I plug in at night with still 20-30% left. Depends on my reception in the day as well, which is pretty bad at work, so I think I'd have 30-35% if my reception at work was good.
deeren said:
Saving power is the same for almost all android devices:
1) turn off mobile network when not in use
2) turn off wifi when not in use
3) turn off gps
4) turn off automatic syns( if you dont use them)
5) brightness set to low
6) turn off live wallpapers
7) use a black wallpaper
8) turn off haptic feedbacks
9) set screen time out to a smaller interval.
all these steps might help you but it kind of takes away the charm of the phone imho.
Click to expand...
Click to collapse
Agreed on all points except for GPS. Since it's an on-demand service, leaving it on makes little to no impact on battery life. The phone only utilizes the GPS connection when an app calls for it and saves you the time of having to toggle it every time you need it. Just leave it on.
RogerPodacter said:
It's definitely the opposite of that, its counter intuitive but WiFi uses significantly less battery life over 3g. I can post some numbers when I get home tonight if anyone's interested. But a good test is leave your phone on WiFi all night, then repeat on 3g and see the enormous difference. Better yet just look at the official Google specs, web browsing time is always higher on WiFi.
I did some real nice graphing of current draw at 2 second sample rate comparing various tasks which is What I'll try to post later..
Click to expand...
Click to collapse
An active WiFi connection uses a lot less than an active 3g connection because the connection already exists and the data transfers faster.
An idle 3g connection uses significantly less energy than an idle WiFi connection. If you aren't using or connected to WiFi, turn it off. Set the WiFi sleep mode to sleep when the screen is off.
Anyone think the Wifi version will have better battery life? I keep my 3G version on airplane mode and just use WiFi. The battery life is OK. I am wondering if it is searching for a wireless signal, but this seems impossible to me. The Wifi won;t do this.
THoughts?
What do you consider OK battery life?
Sent from my Xoom using XDA Premium App
How would the WiFi only version get any more/less battery than a 3G version in Airplane mode with just WiFi turned on?
martonikaj said:
How would the WiFi only version get any more/less battery than a 3G version in Airplane mode with just WiFi turned on?
Click to expand...
Click to collapse
No Idea, But some of the official specs said that battery-life was longer on 3g than wifi.
yeah I get well over 24 hours off of my xoom.
coldbeverage said:
Anyone think the Wifi version will have better battery life? I keep my 3G version on airplane mode and just use WiFi. The battery life is OK. I am wondering if it is searching for a wireless signal, but this seems impossible to me. The Wifi won;t do this.
THoughts?
Click to expand...
Click to collapse
If you didn't run it in airplane mode and it was searching for a signal you would loose battery life. As its in airplane mode, its no different then running the wifi only version.
Sent from my Xoom
agentpower said:
No Idea, But some of the official specs said that battery-life was longer on 3g than wifi.
Click to expand...
Click to collapse
That may be true for some reason, but the OP is asking if the 3G version in airplane mode using WiFi will have better battery life than the WiFi version. Which makes no sense.
The wifi version is the same hardware except it doesn't have the 3G chip so I'm going to take a wild stab and say they'll have the same battery life if using the same functions.
Just so you know, if you have wifi on all the time, it WILL poll for wireless access points which will eat battery. You should only turn on wifi if you're using wifi. Same with phones.
Thank you all.
Sent from my GT-I9000 using XDA App
I've had my sgs2 for a week now and I'm very satisfy with this phone. No problem what so ever. Anyway, I know the phone has this battery saving feature, the data 3g stays at 3g and only change to H only when we download data. So I was wondering if it is possible to get the phone to stay at 2g then goes to H when data is in use? Maybe 1 of the developers here can do this?
Sent from my GT-I9100 using XDA App
That b something id like to have.
Sent from my GT-I9100
Nurra said:
I've had my sgs2 for a week now and I'm very satisfy with this phone. No problem what so ever. Anyway, I know the phone has this battery saving feature, the data 3g stays at 3g and only change to H only when we download data. So I was wondering if it is possible to get the phone to stay at 2g then goes to H when data is in use? Maybe 1 of the developers here can do this?
Sent from my GT-I9100 using XDA App
Click to expand...
Click to collapse
There's an app for that. Maybe Juice Defender? Or something like that, it's one of those. You can set it to only use 3G when the screen is on, and then tell it to go back to 2G when the screen is off, so it isn't as power hungry, and slower data will come in, but it's worth it.
Last night I go to sleep around 1:00 and the battery was 94%. This morning in 10:00 the battery is 90%. I doubt, you can save more then 1% using such app. The only thing that I did is to disable wifi in sleep mode.
Juice defender turn off 3g data when you put the phone to sleep. When you turn it back on, the phone stays at 3g. What I'm try to say is maybe some sort of app that force it to 2g then automatically turn 3g when data is in use. So lets say, I open a web page at 3g speed. after I've found an article I'd like to read, the phone automatically turn to 2g.
Sent from my GT-I9100 using XDA App
By the Way is it possible to only use H+ and to deactivate 3g completely ?
Come on dude 1% is a little right? My sgs2 also has this great battery life when put to sleep. But the problem with our android phones is when we use it continuously. Now obviously from what you are saying, I can tell that your gs2 is in sleep state most of there time. Imagine you spend 30mn reading some threads at xda, watching a movie our listen to music or sending emails..... how much battery life we can save if the phone was in 2g mode?
Sent from my GT-I9100 using XDA App
(•.•) said:
By the Way is it possible to only use H+ and to deactivate 3g completely ?
Click to expand...
Click to collapse
No, 1st it will suck your battery dry. 2nd you don't have H+ coverage everywhere.
Got my LTE upgrade done on my Xoom and now the battery is a joke. I went into settings and disabled the LTE connection, so that now 3g is only used. I also turn wifi on when at home. Currently my Xoom is draining 4ish% per hour while in standby. That means this damn thing won't last a day just sitting there, locked, with no screen on. In Honeycomb 3.0 and 3.1 I could get a days of use with 4-5 hours of screen on time and about 22-26 hours of total unplugged time. Now, under 3.2.2 my battery is totally dead after 18 hours of unplugged time with around 1-1.5 hours of screen use. This is virtually unuseable for taking notes in graduate school after work, when being close to an outlet is impossible.
Any ideas as to what's going on? Tried using Watch Dog and System Panel to see if any apps were going nuts with random CPU usage or RAM usage and everything seems to be in-check in terms of system resource usage. Considering I have 4g totally turned off and wifi enabled when I'm in range of wifi (most of the day) I don't have a clue where this power drain is coming from. Any assistance is highly appreciated given how much I rely on my Xoom for day-to-day use. 3.2.2 seems to have killed it for me.
Please help! Will try any suggestions.
Thanks.
Sent from my Xoom using xda premium
Have you tried disabling mobile data entirely? When I'm in wifi, I disable the cellular connection but haven't performed any in-depth trials on battery life.
"Settings" > "Wireless & networks" > "Mobile networks" > deselect "Data enabled"
Its not just you, mine is the same way it sucks big time. There really isn't anything that I've found to fix it.
I loved how I used to be able more than a day out of a charge...
Anybody have any ideas? Maybe undervolt kernel???
Sent from my Xoom using xda premium
I just received my zoom Lte upgrade and haven't had any battery issues.
PengLord said:
Have you tried disabling mobile data entirely? When I'm in wifi, I disable the cellular connection but haven't performed any in-depth trials on battery life.
"Settings" > "Wireless & networks" > "Mobile networks" > deselect "Data enabled"
Click to expand...
Click to collapse
I haven't but this isn't feasable. I use mobile internet for everything and even take notes and such on Google docs. Even though I'm near wifi for most of a given day, I shouldn't be bothered by manually turning mobile data on and off just to have power- mobile data should be mostly killed when wifi is active. That's how this Xoom worked before. A tablet without internet is nothing more than a paperweight to me. 2 classmates with LTE upgraded Xooms are having identical problems. No fixes found yet. Any other suggestions? This battery life is really, REALLY bad.
Tried going a factory reset and battery life is the same, horrid short, running nothing but stock apps.
Any other suggestions?
Sent from my Xoom using xda premium
wiredup said:
I just received my zoom Lte upgrade and haven't had any battery issues.
Click to expand...
Click to collapse
How long ago did you receive it? The degraded battery seems to have started shortly after the first initial charge after the LTE install.
Sent from my Xoom using xda premium
Same problem here, but I have the mobile network completely turned off and it still does this! Even with the switch to CDMA only!
I will keep reading this thread (only read the about half the posts before posting) so hopefully a solution will show up. But you're not alone in the horrible battery life post LTE upgrade!
I've had my Xoom back since last Wed.
No higher battery drain than previously.
I'm on wifi 90% of the time in home and office.
Yesterday I was all over north San Diego county using 4g. Got home with 60% charge which is about the same as for a prior trip with 3g.
Put your xoom back the way it was. The new hardware sucks the battery a little more. Buy a thunderbolt and then say the xoom battery life sucks. Never charged it during the day before the upgrade. Oh well, that's the price if 4g.
Sent from my ADR6400L using xda premium
Err0xx said:
Got my LTE upgrade done on my Xoom and now the battery is a joke. I went into settings and disabled the LTE connection, so that now 3g is only used. I also turn wifi on when at home. Currently my Xoom is draining 4ish% per hour while in standby. That means this damn thing won't last a day just sitting there, locked, with no screen on. In Honeycomb 3.0 and 3.1 I could get a days of use with 4-5 hours of screen on time and about 22-26 hours of total unplugged time. Now, under 3.2.2 my battery is totally dead after 18 hours of unplugged time with around 1-1.5 hours of screen use. This is virtually unuseable for taking notes in graduate school after work, when being close to an outlet is impossible.
Any ideas as to what's going on? Tried using Watch Dog and System Panel to see if any apps were going nuts with random CPU usage or RAM usage and everything seems to be in-check in terms of system resource usage. Considering I have 4g totally turned off and wifi enabled when I'm in range of wifi (most of the day) I don't have a clue where this power drain is coming from. Any assistance is highly appreciated given how much I rely on my Xoom for day-to-day use. 3.2.2 seems to have killed it for me.
Please help! Will try any suggestions.
Thanks.
Sent from my Xoom using xda premium
Click to expand...
Click to collapse
Download Auto Airplane Mode by DON from the market. It will help BIG TIME!! It does just what the title states, it puts the Xoom into airplane mode automatically as soon as the screen goes off. When you turn the screen back it, the data comes right back in 3 -4 seconds and you're good to go!
Also, you don't have to uncheck any settings or turn 4G off.
Update: Mobile data completely turned off, on wifi only with Xoom sitting about 4 feet from router all morning, so wifi signal was strong. This is the first time I've used the device today. Unplugged at 330am my time, its now 130pm. Device battery is at 60%. 10 hours and 40% of battery gone. That's with mobile data 100% disabled, wifi only- can't even get the Xoom to standby for a full day now. At this current drain rate, it would go from 100% to 0% in one day with no mobile data usage, no screen on time and no usage other than syncing Gmail every 2 hours.
Brother who commented above: Thunderbolt will standby for a full day with no screen on time on wifi only and it has under 1/3 the Xooms battery capacity. I should know- my wife has one and it now outlasts my Xoom. That should not be the case.
From my understanding the Xoom has two 3225ish batteries set up in a sequence. My battery life actually seems to be about half of what it was before. Is it possible that one of the two was disconnected during the LTE radio installation and not properly reconnected? Wasn't sure of the details of how the batteries were set up, but if the Xoom could function with the second battery not working, seems like that would precisely half battery life. Anyone familiar with exactly what had to be done internally to upgrade the radio? Looking at the ifixit teardown of the Xoom, the batteries cover the whole backside- looks impossible to do any internal work on this thing without removing them. Any thoughts?
Cheers,
Landon
Sent from my Xoom using xda premium
Same here. Can't get a full day out of it. Hope a fix will be comming up.
Thunderbolt got the he-man battery and modded my otter box to fit. The xoom battery has entered the battery hog realm after the lte radio. As far as I can tell the radio is cdma/lte together. And it uses power even if wifi is on and data off. It's what I would call big brother watcher. Even if your not connected the radio is txing and rxing something. You know it's lojacked!
Sent from my ADR6400L using xda premium
Interestingly enough, removing the LTE SIM card and using wifi only made no improvement to battery life. I'm assuming the new radio is running at 100% all the time without throttling down, even if absolutely no connection exists or there is a string of faulty battery reinstalls in which only one battery is providing power. That might explain why some people seem to have greater battery issues than others.
Landon
Sent from my Cherryπ 0.8 Atrix. Get yo' slice on.
im glad im not the only one with this problem! its pathetic! im taking my charging cable from my dock with me to work so ill have at least some battery life when i take the train home in the evenings
i to am glad that I'm not alone with this either. I use to charge mine every 4 days with no wifi on and almost no use. Now I get about a day with no use. I mainly use it for web searching and dungeon defenders when I'm home. Horrid battery life for doing nothing. Luckly I mainly only use it at home and am almost always on the dock I got from motor from the upgrade. I use about 4% an hour also with nothing on. Mine is completely stock with no root.
Yahoo mine is stock with absolutely no root or other mods. I guess they knew about the pissy battery life and that's why they gave a free dock. Lol. Still trying to find exactly what's killing the battery. LTE does drain a lot of juice but as I've stated before my wife has a Thunderbolt and per mW of battery power, the thunderbolt is more efficient and that's not saying much. It can standby for over a day with no use fine and it has roughly a little less than 1/3 the Xoom battery capacity. Something isn't right. Its not supposed to be this bad. Anyone filed a complaint/tech request with moto/Verizon? I think its something that we should all do and report what they say here. I have a feeling more and more people are gonna have this issue if they do the upgrade. Maybe if enough of us make some noise, something will be done.
Landon
Sent from my Xoom using xda premium
Maybe it's not the radio.
3.2.2 may have some kind of interaction with something you guys were running that's causing wake locks to get stuck
Did you look at Settings:About Tablet: Battery Use ?
(tap on the histogram at the top for another, see if the time spent awake is solid or different from screen on)
I tested this on mine, with the mobile data disabled and lost about 1% battery every hour, this is on par with the performance I had pre-upgrade.
Rooted, stock kernel
I realize it does not help you but you might look somewhere other than the wireless radio for the problem. I unplugged my upgraded Xoom yesterday morning around 8:30 AM. It is now 8:20 AM and my battery is at 66%. I was on 4G for about 2-3 hours yesterday, the rest of the time on wifi. I check and respond to my mail on the Xoom so it saw some use yesterday, though not as much as I normally do.
I'm on ec05 un rooted.
I've noticed a problem that started a few months ago. Before I get into that...some things to know:
I have 5 batteries. 1 stock and 4 aftermarket.
One issue I have is battery drain. If I'm not on wifi then I get between 2-4 hours. With wifi it is 5-7.
Whenever I change the battery it is a toss up as to whether all of my apps will load. I have rebooted 5 times today within a 30 min period. All the apps still haven't loaded and battery life dropped 20%. I have tried using the keys to reboot and also taking the battery out.
The phone will also get hot when not on wifi.
Any suggestions on how to fix? I have tried factory reset and it doesn't fix it.
Sent from my SPH-D700 using XDA App
If you're already willing to factory reset, you might as well Odin back fresh and see if it helps. Unfortunately root is needed to calibrate the battery in traditional ways.
If you have 5 batteries and have to swap out every 5 hours then your probably on your phone all day.
Are you just pulling the battery or letting it power down? I know stock has journaling on which protects you from if the battery gets pulled but after o long it ill catch up and do it mine has but I get why better battery life then that. My wifi on I will get about 15 hour with little bit of use but I will get about 6 to 7. When running pandora at work the whole time and maybe mess around with it for 30 mins. Also make sure you back out of everything
Sent from my SPH-D700 using xda premium
I would bet you've got some app installed that is constantly running in the background, constantly connecting and downloading data and killing the battery. Since WiFi uses less power than 3G you get better battery life on Wifi, but if you are constantly syncing and downloading you are going to kill the battery.
If you go into settings>accounts and sync and look at what's syncing it may give you a start. You could also go int settings>about phone>battery use and see what's using the most power.
The only thing that is set to sync is gmail.
The display is using 91% of the battery. Even if I don't use my phone much during the day, the display still shows 90% or higher.
Sent from my SPH-D700 using XDA App
jmb521 said:
The only thing that is set to sync is gmail.
The display is using 91% of the battery. Even if I don't use my phone much during the day, the display still shows 90% or higher.
Sent from my SPH-D700 using XDA App
Click to expand...
Click to collapse
The display is always the biggest drain. That is based on 100% of what you have used. If your battery is warm while not on wifi you are losing 3G and your phone is constantly trying to connect to sync. Put it in airplane mode for an hour and see how the drain is. My guess is a tower is down near you or under maintenance.
Sent from my SPH-D700 using XDA App
When wifi is on means 3g is off. And cdma 3g uses ALOT of battery because is has no type of "sleep mode" meaning it is on 24/7 and when you do use it it is a battery hog because it also uses a lot to power the cdma bands. Just another cheap flaw in the life of sprint.
So when you are not on wifi turn off 3g.
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