Didja Know? WiFi Sleeping

[justbob]

Keeping the wifi on all the time shouldn't be a big drain on your battery as long as you have a reasonably good signal from your access point, because the phone doesn't have to turn up the transmitter power to reach out and touch it. We all know that it's the transmitter that chews-up your battery, not the receiver. When not actively using wifi, the only time your phone will transmit is to periodically renegotiate encryption keys or a DHCP lease and each of those transactions are very short (< 10 packets), so in the grand scheme of things the additional drain should be negligible.

Another thing is that the phone will not try and scan for new access points. It only listens for incoming transmissions and will try and associate with ones that it recognizes. It's completely opposite from the way the cellular radio works.

 

[CYBER DROIID]

See now this is why I completely love and loath this phone, I learn something new every day. I love learning something new about my phone every day BUT can all this NOT be written down some where geeeeeeeeeeezzzzzzzzzz

 

[Jonny Kansas]

@Justbob: Your bottom paragraph is a great point. That was my original question.

So far, after 2hrs 45mins unplugged with wifi set to not sleep and turned on, wifi battery percentage is at 17%. I've done some browsing/posting here, searched the market a bit, and downloaded one app so far. Also used bloo a couple times to check and post on facebook. I THINK that uses wifi when activated. Seems faster with wifi on.

Wifi % use peaked at 20% so far, then was at 19%, then the 17% I've already reported. (Before stating this post, I returned home to check it.)

So far, seems like allowing wifi to stay awake doesn't have much effect on battery!

 

[dtu]

I am curious what this really affects. Mine was set for off when Screen is off. I use my wifi all the time. I will listen to Pandora or podcasts chilling in bed. I will hit the power button to turn off the screen and wifi isn't affected

 

[640k]

I am curious what this really affects. Mine was set for off when Screen is off. I use my wifi all the time. I will listen to Pandora or podcasts chilling in bed. I will hit the power button to turn off the screen and wifi isn't affected

pandora buffers, so there's time to switch between networks. the same thing happens as you're driving and sweeping towers. keep your setting in off while sleep and turn off 3G and report back.

 

[mtbhk44]

In my "unprofessional opinion" (I slept at a Holiday Inn Express last night - booo, terrible I know), if you have a solid 3G connection at home and a solid WiFi connection at home, this will likely not make a difference. If you have a spotty 3G connection at home and your phone is constantly hunting for 3G service but a good WiFI connection, then this will most definitely SAVE battery life. If you don't have a solid WiFi connection at home, this will obviously cause battery drain if WiFi is always on, hunting for a signal.

I have found that at my mother in law's house where she has ZERO 3G service AND zero WiFi service, aside from a weak 3G signal in one room, I will burn through my battery in about 7 hours (if I am there that long) whether Wifi is on or not. At home, with WiFi on constantly, I can go 27 hours with moderate use and not burn through my battery.

So in conclusion, if you have solid 3G/WiFi signals, it will likely not make a difference other than the fact that if you don't have your WiFi set to "always on" the phone will look for that WiFi signal when you wake up the phone. That will take up a little bit of juice.

I leave my WiFi to "always on" but toggle it off with a Beautiful Widget when I leave my house or wherever I no longer have a solid WiFi connection. Make sense? Just my two cents.

 

[Jonny Kansas]

Ok. Had my phone unplugged for around 12 hours with my wifi sleep policy set to Never while plugged in. For 6 of those hours, I was awake browsing Droid forums occasionally, checking email, searching the market, downloading an app or two.

For the other six, I was asleep, so my phone sat idle.

Now, I've set the wifi sleep policy to never and plugged my phone back in for a little while to reset the battery usage %s.

I'll do my best to use the phone about the same way I did before.

Battery usage of wifi, toggle on, but allowed to sleep when the screen was off was listed at 14% after those 12 hours.

I have a feeling the biggest change will be in the idle time. Any other predictions?

Almost 4 hours in, and Wifi Battery use % is at 14. Seems to be the same either way [Sleep when screen is off OR Never sleep].

As stated above, I used my phone for 5 hours before, and in the last 4 hours, have actually done MORE web browsing and etc than I did in those 5 hours, so it seems as though:

If you're connected to a network and have a good signal, setting WiFi Sleep Policy to "Never" rather than the default "Sleep when screen is off" has no effect on battery

However, I'm sure it's safe to assume that you should DEFINITELY turn WiFi off when leaving your home, office, or wherever you're using WiFi, as I would imagine it will continuously send out information to search for new networks as opposed to only scanning when the screen is turned ON with the default setting. [Anyone who knows more about the frequency of network search on Android, please feel free to correct me or add to this statement, but I assume if it's set to sleep while the screen is off, it's not actively searching for a network when the screen is off and you're not connected to a network.]

 

[Jonny Kansas]

In my "unprofessional opinion" (I slept at a Holiday Inn Express last night - booo, terrible I know), if you have a solid 3G connection at home and a solid WiFi connection at home, this will likely not make a difference. If you have a spotty 3G connection at home and your phone is constantly hunting for 3G service but a good WiFI connection, then this will most definitely SAVE battery life. If you don't have a solid WiFi connection at home, this will obviously cause battery drain if WiFi is always on, hunting for a signal.

I have found that at my mother in law's house where she has ZERO 3G service AND zero WiFi service, aside from a weak 3G signal in one room, I will burn through my battery in about 7 hours (if I am there that long) whether Wifi is on or not. At home, with WiFi on constantly, I can go 27 hours with moderate use and not burn through my battery.

So in conclusion, if you have solid 3G/WiFi signals, it will likely not make a difference other than the fact that if you don't have your WiFi set to "always on" the phone will look for that WiFi signal when you wake up the phone. That will take up a little bit of juice.

I leave my WiFi to "always on" but toggle it off with a Beautiful Widget when I leave my house or wherever I no longer have a solid WiFi connection. Make sense? Just my two cents.

Makes perfect sense. Seems as though our statements agree. I don't have HORRIBLE 3G at home, but it's definitely not "solid." I don't seem to miss calls or anything, but I never have full bars.

 

[640k]

Ok. Had my phone unplugged for around 12 hours with my wifi sleep policy set to Never while plugged in. For 6 of those hours, I was awake browsing Droid forums occasionally, checking email, searching the market, downloading an app or two.

For the other six, I was asleep, so my phone sat idle.

Now, I've set the wifi sleep policy to never and plugged my phone back in for a little while to reset the battery usage %s.

I'll do my best to use the phone about the same way I did before.

Battery usage of wifi, toggle on, but allowed to sleep when the screen was off was listed at 14% after those 12 hours.

I have a feeling the biggest change will be in the idle time. Any other predictions?

Almost 4 hours in, and Wifi Battery use % is at 14. Seems to be the same either way [Sleep when screen is off OR Never sleep].

As stated above, I used my phone for 5 hours before, and in the last 4 hours, have actually done MORE web browsing and etc than I did in those 5 hours, so it seems as though:

If you're connected to a network and have a good signal, setting WiFi Sleep Policy to "Never" rather than the default "Sleep when screen is off" has no effect on battery

However, I'm sure it's safe to assume that you should DEFINITELY turn WiFi off when leaving your home, office, or wherever you're using WiFi, as I would imagine it will continuously send out information to search for new networks as opposed to only scanning when the screen is turned ON with the default setting. [Anyone who knows more about the frequency of network search on Android, please feel free to correct me or add to this statement, but I assume if it's set to sleep while the screen is off, it's not actively searching for a network when the screen is off and you're not connected to a network.]

new test. wifi never sleep, exist in a 3G only area, with spotty wifi coverage, but never connected. i get spotty 3G here, with a wifi spot, that isn't an internet connection. let's seee how long i can go without using my phone.

 

[Jonny Kansas]

new test. wifi never sleep, exist in a 3G only area, with spotty wifi coverage, but never connected. i get spotty 3G here, with a wifi spot, that isn't an internet connection. let's seee how long i can go without using my phone.

I like it. Looking forward to the results!

 

[Jonny Kansas]

Our suspicions confirmed...

So, I just left home to take my cousin/roommate to work and stop at the gas station [won $7 on the lotto!!! Haha!], and then stopped next door to drop of my grandma's mail. Gone MAYBE 30 minutes...between 20-30.

All the while, I still had WiFi enabled. [Remember, I set it to "Never Sleep"].

I had an update to my Battery Left Widget [just keeps getting better], and one of the new features is that you can now check usage and stats from the info screen that comes up when you click the widget.

Well, of course, I had to try it out...

WiFi battery usage %...31!

In the 5-10 minutes I've been home [and reconnected to my network] it's already dropped to 25%.

Just confirming what we already know really...If you're not connected, and are searching for networks, WiFi eats battery like a champ!

 

[640k]

battery usage meter is not a defnite indication of "eating battery liek a champ", it just shows that the wifi is the #1 item consuming the battery's resources. so if your phone was off (sleep) for the entire time, wifi would surely be #1.

but it just goes to show what the difference in on/off makes in the setting.

now try this, play a game for 2+ hrs, with wifi on, but not connected to a spot. does wifi beat out the display?

i think display will still edge out wifi as it consumes more resources than wifi does (see the relation).

 

[jsh1120]

Ok. Had my phone unplugged for around 12 hours with my wifi sleep policy set to Never while plugged in. For 6 of those hours, I was awake browsing Droid forums occasionally, checking email, searching the market, downloading an app or two.

For the other six, I was asleep, so my phone sat idle.

Now, I've set the wifi sleep policy to never and plugged my phone back in for a little while to reset the battery usage %s.

I'll do my best to use the phone about the same way I did before.

Battery usage of wifi, toggle on, but allowed to sleep when the screen was off was listed at 14% after those 12 hours.

I have a feeling the biggest change will be in the idle time. Any other predictions?

My God! Someone who is actually doing an experiment. I'm impressed. As an old professor of mine was fond of noting, "One thing about data is that it sure cuts the b******t."

 

[Jonny Kansas]

battery usage meter is not a defnite indication of "eating battery liek a champ", it just shows that the wifi is the #1 item consuming the battery's resources. so if your phone was off (sleep) for the entire time, wifi would surely be #1.

but it just goes to show what the difference in on/off makes in the setting.

now try this, play a game for 2+ hrs, with wifi on, but not connected to a spot. does wifi beat out the display?

i think display will still edge out wifi as it consumes more resources than wifi does (see the relation).

Right. Sorry. I meant comparatively speaking. Anyone know of an app that shows more detailed battery usage? Ie. How much power the things on the usage list ACTUALLY use, rather than how much they use compared to eachother?

My God! Someone who is actually doing an experiment. I'm impressed. As an old professor of mine was fond of noting, "One thing about data is that it sure cuts the b******t."

Haha! I wanted to know, so I checked it out. As I stated previously in this post, I'm basically ALWAYS connected to WiFi when I'm home, so I wanted to figure out what the impact was like while I had time to recharge my battery. Had last night off, so it worked out that I was able to check it out just a little bit. I'm sure more thorough experiments could be conducted.

 

[640k]

Right. Sorry. I meant comparatively speaking. Anyone know of an app that shows more detailed battery usage? Ie. How much power the things on the usage list ACTUALLY use, rather than how much they use compared to eachother?

nah, what you get is pretty accurate. it's like when your car tries to average your mpgs. you just have to realize that the usage is "in the moment" and that you won't get an accurate picture until the battery is almost drained.