Does WiFi drain your battery?

Jeremiah Bonds

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I'm just curious.

When I was with Sprint 4 years ago, WiFi used to extend my battery life, by a lot. Ever since I switch TMobile, it seems like when I use WiFi, my battery drains faster, maybe the T-Mobile network is just pretty good in my area?
 

RaRa85

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Wi-Fi does wonders and I'm on T-Mobile as well. This was from today. In the house all day on Wi-Fi.
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RaRa85

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Hard to tell much about the battery from just screen on time.
Screen brightness at 37%. No gaming. Light browsing between PhoneArena, the Verge and Instagram through the browser not the app. Watched a few YouTube videos. Back and forth between Tapatalk forums and Flickr app. Looking through my photos. In and out of NFL Mobile and ESPN apps. But the phone has been on and in use for 5 hours with 30% left without any kind of intentional battery saving methods. I can't complain.
 

Almeuit

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Screen brightness at 37%. No gaming. Light browsing between PhoneArena, the Verge and Instagram through the browser not the app. Watched a few YouTube videos. Back and forth between Tapatalk forums and Flickr app. Looking through my photos. In and out of NFL Mobile and ESPN apps. But the phone has been on and in use for 5 hours with 30% left without any kind of intentional battery saving methods. I can't complain.
Easier to just snap the pic of the screen before the screen on time ;).
 

natehoy

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I guess no one has worse battery when on WiFi, but me?

WiFi is usually more power-efficient because you are transmitting requests and acknowledgments (usually) at lower power and for less time to transfer the same amount of data, so you are using less power overall. WiFi access points are short-range and you are transmitting to them in the 30-milliWatt range. Cell is longer range and you are usually transmitting closer to the 250mW range to punch a signal through unless the tower is really close. There are other power draws involved than transmission, but basically WiFi will be ~8 times less "hungry" than cell data - all other things being equal (both being at the same number of bars, etc).

However, all other things are rarely equal. If you are on weak WiFi, you might be getting 1mbps and losing packets intermittently which requires a re-send, so effectively you may be getting half that. So you are transmitting at the full 30mW asking for retries all the time to get an effective throughput of 500kbps.

If at the same time you are on strong LTE (so your phone is transmitting a much weaker signal to reach the tower, so it might only need to transmit at 100mW) and it can provide you with 20mbps of reliable speed, then you are effectively receiving data up to 40 times faster than a weak WiFi signal at a cost of about three times the effective power consumed.

Plus, of course, you may have apps that are trying to sync only when connected to WiFi. Google Photos, for example - if you have that set to only sync when it is on WiFi, it doesn't matter how good your WiFi is - there are data-intensive activities going on only when WiFi is connected and they are gonna draw a lot of power to get 'er done. As soon as you turn off WiFi, those apps shut down and your battery holds up better because your phone is simply doing less work.
 

Ntchwaidumela

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I guess no one has worse battery when on WiFi, but me?

Are you sure it's on wifi the entire time? And that it didn't switch itself over to the network? I ask because I've come home from work and my phone was still on the network and didn't switch over to wifi automatically. I manually switched it. In that case, the battery use over the network might have been a little more, even though my network reception at home is 4-5 bars all the time.
 

Jeremiah Bonds

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yeah I'm pretty sure. I can see a drop in battery life as opposed to when I'm on my network.. Maybe the wifi at my office doesn't bode well with my phones?
 

B. Diddy

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I haven't done a rigidly controlled study, but I also have noticed that battery seems to run down a bit faster on my Nexus 6P when wi-fi is turned on. I'm on T-Mobile, and get decent signal at home.
 

recDNA

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yeah I'm pretty sure. I can see a drop in battery life as opposed to when I'm on my network.. Maybe the wifi at my office doesn't bode well with my phones?
Last night my wifi was off, in fact it was off all day, I went from 100 percent at bedtime to 98 percent when I got up but batter use said 1 percent of battery was used by wifi! I double checked. Wifi is off. Weird.
 

B. Diddy

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Last night my wifi was off, in fact it was off all day, I went from 100 percent at bedtime to 98 percent when I got up but batter use said 1 percent of battery was used by wifi! I double checked. Wifi is off. Weird.

Is wi-fi scanning turned on? That can be found in different locations depending on the phone On my Nexus 6P, it's in Settings>Location, then Menu>Scanning>Wi-Fi Scanning. On the Note5, it's in Settings>Privacy>Location>Improve Accuracy​. Not sure where it is on the V20.
 

recDNA

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Is wi-fi scanning turned on? That can be found in different locations depending on the phone On my Nexus 6P, it's in Settings>Location, then Menu>Scanning>Wi-Fi Scanning. On the Note5, it's in Settings>Privacy>Location>Improve Accuracy​. Not sure where it is on the V20.
Yes it is on. Perhaps. that explains it. Good catch. What do you think of using Qualcom lZat to improve location and save power. I use location every day in navigation​ so it isn't worth shutting it off just to turn scanning back on.
 

B. Diddy

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I've found that GPS without wi-fi scanning works just fine for precise location, so if you don't mind having Location set to High Accuracy all the time, you probably won't notice any difference in precision with wi-fi scanning off. Sorry, I don't know much about iZat -- here's an article, in case you want to know more: What is the Qualcomm iZat in Android's Location Settings
 

Brent Michael

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I just turned both WiFi scanning and Bluetooth scanning in location settings so that should help some. I always, well almost always, turn WiFi off when I'm not at home. I just hate it constantly searching for crap. I used to use the smart settings for it but it was so unreliable that I stopped.
 

TNCattleDog

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I use IFTT to manage my WiFi and it seems to make a difference turning it off when I'm not connected at work and at home. I also use "high accuracy" for location, but I have not turned off wifi and bluetooth scanning...which I will try today.

Part of my reasoning for turning it off when not at home or work, is that I don't want it to try to connect to all the open wifi networks along the way while I am driving...including the many hotspots in peoples cars that are set to open/available.

Funny thing is depending on which side of my office I am on, (poor wifi and good wifi) it does make a difference in my battery life.

That said, I am in a good 4G LTE area so I can usually finish out a busy day with about 3.5+ SOT and 15 hours of use with about 30% battery remaining.

David