This is a discussion on Keeping WIFI on all the time within the Nexus One forums, part of the Google Phones category; Originally Posted by Beer Goggles Originally Posted by Snickolaz One of the first things I did was change the WiFi to never sleep, that way ...
3G/Edge DOES NOT stay on for Data, only for voice. Since the official google forums weren't good enough, I thought, just for extra measure, maybe the good folks at XDA might satisfy your demand for credibility. There is plenty more anecdotal proof for the claim, just Google it.
Also check out the screens below, which illustrate the point better.
WI-FI sleep policy - Android Help
Holy crap. Change wifi sleep policy to never. BIG INCREASE IN BATTERY - xda-developers
Indeed, random people on the Internet are not automatically credible. No matter to which forum they are posting.
There seems to be a great deal of confusion due to imprecise or incorrect use of terms.
First, your phone always tries to stay "connected" to the cellular network in the sense that it needs to make itself known to the cellular network and maintain this "connection" in able to do anything at all within that network (voice or data). That "connection" is always ON unless you lose signal completely. The Wifi network is very similar. So there is always some transmit/receive going on just to keep on the cellular network.
Secondly, what really consumes power is transmitting data. The 3G transmitter definitely uses more power then the Wifi. It must typically transmit over a much greater distance, so that only makes sense.
Thirdly, in a digital network (cellular) voice is data (just not that much data).
So your phone never "disconnects" from the 3G/EDGE network just because you're using Wifi. But, it does not need to use 3G/EDGE for Internet traffic so there is very little transmit/receive going on over the cellular radio (saving power).
Now, if you have a TON of background processes that require Internet data, then leaving Wifi on all the time might help battery life. If you don't, then it will hurt battery life. This is why it's all very dependent on how you're using the phone.
By the way, WiFi stays up fine on my N1 using MoDaCo's Desire Rom. So its definitely not a hardware issue.
Ive read that your phone goes off 3g and into 2g, that may or may not be true but doens't matter.
Because some people live in an area where their phone will switch back and forth from whateverG to edge, while on edge your phone uses a considerable amount of battery looking for a 'g' signal instead.
Your phone will record this information to you under: settings -> about phone -> Battery Usage. Under cell standby or phone idle (i can't remember which) it will tell you how much you were 'out of network' and will tell you that drains battery.
Whether for the normal guy this helps or not I have no idea, but I will try it out and see.
Will this only affect it being on in 'sleep' when wifi is on? it wont affect anything with wifi turned off correct?
Nexus One and luvin it
Enomther 2.10.1 Froyo Release
Being on 2G is NOT "out of network". Out of Network is when you are connected to a tower that does not belong to your carrier. Out of Network is ROAMING.
This has had a significant effect for my phone.
I set WiFi to never sleep and switched preferred network to "GSM auto (PRL)" (items "A" and "B" in that first Google forums post that was linked) Everything seems to work well, and I still get 3G just fine when outside of a WiFi hotspot.
Admittedly, I'm a light user of my phone, but even then I'd typically be at ~75-80% at this point in the day (4:30pm here now, took the phone off the charger at 8:15am). I have WiFi both at home and at my workplace.
It's currently sitting at 94%.
I'm curious about exactly what the Android WiFi "sleep" is doing. From how my phone behaved before (not showing the WiFi icon at all if I unlocked it after a good while not being used, and then appearing and connecting 3-5 seconds after the unlock) I was assuming WiFi "sleep" meant it actually shut off the connection and fully removed power from the WiFi radio.
But, if you have WiFi "sleeping" like that and your phone wants to transmit data (say, syncing your Google account stuff), does it silently power the WiFi back up temporarily to do so, or would it just use 3G/EDGE? It seems the power savings from forcing WiFi to stay on would only be realized if this were the case (or if re-negotiating the WiFi connection each time really took a lot of power).
From what I understand most modern WiFi chips can idle at extremely low power draw if not transmitting data but while still maintaining their connection to the access point. If this is what is happening when you force it to never sleep, it seems reasonable that it might have an impact, particularly if you're most often in a hotspot.
Then again, I did change two settings at once, so I can't really say which is responsible, or how much each is contributing to the difference.
It'd be interesting to do a more controlled test of both the WiFi sleep setting, and the preferred network versus defaults. Seeing how they impact battery life both with and without a hotspot for the WiFi to connect to. Maybe I'll try that sometime (if I can find several days where I don't need to use my phone! )