Help WiFi using battery when turned off?

[JBentleyR]

Hi. Can anyone tell my why, on my 'Battery - History Details', WiFi appears to be on all of the time?
The 'Mobile Network Signal' bar (incidentally, what do the variations in colour mean?) and the 'WiFi' bar run across the whole width of the screen, yet I turn WiFi off except for when I need it and only when the screen is on.
I am assuming that the WiFi bar indicates when a WiFi signal is being detected, even when I have turned WiFi off, yet whilst 'Screen' accounts for 28% of battery usage, 'WiFi' accounts for 26%.
Although I have not been using my phone much over the last day and a half, the battery has now discharged down to 19%.
I'd be very grateful for any advice.

 

[Hadron]

I can tell you that the colours indicate the strength of the mobile signal. It looks like you don't spend much time in strong signal areas (there's almost no green in that bar), which will reduce battery life.

One thought on the WiFi thing: in your Settings > WiFi > Advanced is the setting "Scanning always available" selected? That lets Google's location services (and possibly others) scan for networks even if WiFi is off - which of course means that WiFi isn't really off, just that it's not trying to connect. I always have this disabled, and indeed don't use wireless location at all, so don't know whether this would show up in the battery history, but it seems like a possibility.

 

[JBentleyR]

Thank you very much, Hadron.

Yes, 'Scanning always available' was selected; I have turned it off now, but presumably it will turn on if I turn on WiFi and turn off when I turn WiFi off.

Thanks for the information about the colour. Presumably, then, green is good signal, through yellow to red for poor or non-existent. I hadn't found that information anywhere else. To be honest, unless I'm going out Mobile signal is turned off as reception is not too good in my house (not that that matters as I use WiFi if I need a data connection at home). Although Mobile data is turned off whilst I'm at home, does the poor signal still affect battery life and, if so, what can I do about it?

Just incidentally, I have tried posting these questions here several times, but the site would not accept my post and I had no idea why not. I finally discovered that I needed to attach the screen shot as a thumbnail as full-sized picture failed to work. Again, I couldn't find any help topic along these lines on the site.

Thanks again for your help.

 

[Hadron]

There have been a few glitches with the site lately. I've generally found that just hitting the post button a second time has worked.

Yes, those are the colours, and a gap would mean exactly what it looks like. Poor signal will degrade battery life if data is off, as the phone will still be using more power maintaining the network connection. The very worst is if coverage is weak enough that it's constantly dropping the connection then trying to reconnect. Swapping bands also uses power, so if you are in a location with solid 2G but marginal 3G you would save power by switching to 2G only mode (of course that's one more thing to switch back later). Otherwise there's not a lot you can do about it, unless you can get a femtocell installed.

And yes, if you turn off the "scanning always available" it just means that it can't use WiFi for location when you think that WiFi is turned off - it will not stop it being used when WiFi is turned on.

And actually I can rarely remember how to attach plots as thumbnails, even though that would often be convenient!

 

[JBentleyR]

Thanks again.

I have 'preferred network type' selected as 4G, which says 'recommended', although there are not many areas around here that have 4G.

I've changed it to 3G. I wonder whether that might make a difference.

 

[Hadron]

It might. Fingers crossed.

 

[JBentleyR]

Well, since turning off 'scanning always available' there has been an enormous improvement in battery life. When I turn on WiFi, it still connects (to my home network) almost immediately, so no drawbacks there.

Also, since changing 'preferred network type' from 4G to 3G, the mobile network signal bar (in battery history) is a continuous greeny-yellow, whereas previously there was quite a broad variation in colour, so it's possible that may have helped a little with battery life too.

Thanks again for your 'Ace' advice, Hadron!

 

[DoktaBob]

For even better battery saving look at the app called LeanDroid... Besides all other apps, that promise battery life improvement this is the only app that really works... It has a clever Wifi/GPS/Data managment that deactivates unnecessary things while screen is turned off. The developer is very active and answers questions very fast.