Battery life issue - iTunes Wi-Fi sync???

parish

macrumors 65816
Original poster
Apr 14, 2009
1,082
1
Wilts., UK
For the first few weeks after getting my 4S my battery life was excellent, the suddenly it went bad...

Originally:

Charged to 100% at night, ~95% in the morning, and ~35% when I got home from work

Now:

Charged to 100% at night, ~80% in the morning, and ~20% when I got home from work

Been trying everything, and doing some serious head scratching. Then I realized that the daytime usage was the same - ~60% - for both scenarios so the big drain was only overnight :confused::confused:

At home I have W-Fi, but during the day at work only 2G cellular.

So, it seems to only be a problem when on Wi-Fi :confused:

Finally, I worked out that I didn't enable iTunes Wi-Fi Sync until I'd had the phone a few weeks (it's disabled by default) although I can't be certain that the change in battery drain coincided with enabling iTunes WiFi sync, but it was certainly around that time.

I'm now thinking that my phone is searching for my MBP (which is turned off) all night trying to sync to iTunes. This would explain the big overnight drain.

Tonight I'm going to disable Wi-Fi Sync (has to be done from iTunes) and see if the battery drain rate goes back to how it was.

Does anyone else with poor battery life have Wi-Fi Sync enabled?

I would guess that if you have any Wi-Fi connection then it will try to sync, even if it's not your own home W-Fi - which may explain why some people have really massive battery drain as they may have a Wi-Fi connection at work etc.
 

Thetonyk123

macrumors 68000
Aug 14, 2011
1,627
1
Earth
For the first few weeks after getting my 4S my battery life was excellent, the suddenly it went bad...

Originally:

Charged to 100% at night, ~95% in the morning, and ~35% when I got home from work

Now:

Charged to 100% at night, ~80% in the morning, and ~20% when I got home from work

Been trying everything, and doing some serious head scratching. Then I realized that the daytime usage was the same - ~60% - for both scenarios so the big drain was only overnight :confused::confused:

At home I have W-Fi, but during the day at work only 2G cellular.

So, it seems to only be a problem when on Wi-Fi :confused:

Finally, I worked out that I didn't enable iTunes Wi-Fi Sync until I'd had the phone a few weeks (it's disabled by default) although I can't be certain that the change in battery drain coincided with enabling iTunes WiFi sync, but it was certainly around that time.

I'm now thinking that my phone is searching for my MBP (which is turned off) all night trying to sync to iTunes. This would explain the big overnight drain.

Tonight I'm going to disable Wi-Fi Sync (has to be done from iTunes) and see if the battery drain rate goes back to how it was.

Does anyone else with poor battery life have Wi-Fi Sync enabled?

I would guess that if you have any Wi-Fi connection then it will try to sync, even if it's not your own home W-Fi - which may explain why some people have really massive battery drain as they may have a Wi-Fi connection at work etc.
I never had wifi sync on, because I heard it does drains battery, which I guess it does.
 

mikemj23

macrumors 6502
Jul 27, 2010
375
124
If you have the iTunes Wi-Fi Sync enabled, the only time your iphone tries to sync with iTunes while connected to a wi-fi network is when it is plugged in and charging so there shouldn't be an impact on battery life.
 

HazyCloud

macrumors 68030
Jun 30, 2010
2,749
13
If you have the iTunes Wi-Fi Sync enabled, the only time your iphone tries to sync with iTunes while connected to a wi-fi network is when it is plugged in and charging so there shouldn't be an impact on battery life.
I originally thought that as well until I realized iTunes has to be pinging your phone to make sure it's still available. Your phone may only look for iTunes when it hits power, but who's to say iTunes isn't constantly looking for your iPhone?
 

mikemj23

macrumors 6502
Jul 27, 2010
375
124
I originally thought that as well until I realized iTunes has to be pinging your phone to make sure it's still available. Your phone may only look for iTunes when it hits power, but who's to say iTunes isn't constantly looking for your iPhone?
Once your iPhone hits power it tries to connect to iTunes and sync. Plugging an iPhone into a power source while you are connected to Wi-Fi initiates the process. Seems to me that iTunes constantly pinging your iPhone wouldn't make much sense, but what do I know.

Besides, I've had it enabled and disabled and have not seen any difference in battery consumption either way.
 

orpheus1120

macrumors 65816
Jan 23, 2008
1,318
10
Malaysia
I originally thought that as well until I realized iTunes has to be pinging your phone to make sure it's still available. Your phone may only look for iTunes when it hits power, but who's to say iTunes isn't constantly looking for your iPhone?
Well I can guarantee that iTunes isn't pinging your devices constantly. This is how you can verify for yourself.

Make sure you are using wifi sync and you are connected to your network. Ensure your device is showing up on iTunes. Now turn off wifi on your device. Now will you still see your device in iTunes? Yes of course. If iTunes is constantly pinging your devices, they should not show up in iTunes after awhile.

I have constantly left my home with my idevices, and returining only to find out all my devices are still listed in iTunes (wifi isn't turned on on my devices then, I turned off wifi for my devices when bringing them out.).

The only time iTunes "ping" your devices is when you initiate a sync ether from your devices or from iTunes.
 

mikemj23

macrumors 6502
Jul 27, 2010
375
124
My iPhone 4 is on wifi 99% of the time, and it doesn't drain battery any more than anything else for me.
OP is talking about having Wi-Fi Sync enabled between your iPhone and iTunes Library, not just having Wi-Fi on in general.

Was just clarifying.
 

phaggard

macrumors regular
Sep 28, 2007
139
0
I have come home from work and go into Itunes and there is a popup stating that Itunes tried to connect to an Iphone but could not indetify the phone. Reconnect with a cable to reconnect.
 

mikemj23

macrumors 6502
Jul 27, 2010
375
124
I have come home from work and go into Itunes and there is a popup stating that Itunes tried to connect to an Iphone but could not indetify the phone. Reconnect with a cable to reconnect.
could you be more specific? is it a 4s? do you have wi-fi sync enabled?

I've seen your pop up before and it can happen sometimes when updating to the newest version of iTunes.

Just trying to decipher if the pop up has anything to do specifically with wi-fi sync.

thanks.
 

orpheus1120

macrumors 65816
Jan 23, 2008
1,318
10
Malaysia
I have come home from work and go into Itunes and there is a popup stating that Itunes tried to connect to an Iphone but could not indetify the phone. Reconnect with a cable to reconnect.
You aren't being specific. Was your iPhone connected to wifi and you trying to wifi sync to your iPhone? There are several reasons why you are seeing the pop up.

1) Your iPhone isn't connected to wifi and you try to wifi sync to your iPhone via iTunes. iTunes will not be able to see your iPhone.

2) sometimes when your iPhone reconnects to your network after prolonged period of not connecting to your wifi (bringing out your iPhone outside etc, or simply turning wifi off etc), your iPhone is assigned to a different ip via DHCP when it connects back to your network. I suspect iTunes keeps a record of each device with wifi sync enabled AND their corresponding ip addresses. Hence when you try to wifi sync under this condition, it will sometimes fail if the current device ip address doesn't correspond to the one in iTunes' record.

3) iTunes tried to wifi sync that you initiated previously and it failed to detect your phone for some reasons. One would also see such a pop up. But if you aren't paying attention or not looking into your Mac you won't notice it.
 

parish

macrumors 65816
Original poster
Apr 14, 2009
1,082
1
Wilts., UK
the only time your iphone tries to sync with iTunes while connected to a wi-fi network is when it is plugged in and charging so there shouldn't be an impact on battery life.
Yes, I know that is how it's supposed to work. What I was wondering is if it's not working correctly, i.e. the phone is constantly trying to find my MBP even when it's not on charge. It's obvious that something in iOS5 isn't working correctly.

Like everyone else, I don't know what the problem is and I'm just trying to work out why mine went bad after ~3 weeks of no problems.

http://www.buxbusters.com has identified this as the, or at least a possible, cause.

Having said that, I disabled Wi-Fi Sync last night and this morning it was even worse - only 58% :confused:

Usage stats showed

Usage: 3h 3m
Standby: 6h 38m

even though the phone had not been used since taking it off charge.
 

BuxBuster

macrumors newbie
Dec 24, 2011
7
0
The Netherlands
Yes, I know that is how it's supposed to work. What I was wondering is if it's not working correctly, i.e. the phone is constantly trying to find my MBP even when it's not on charge. It's obvious that something in iOS5 isn't working correctly.

Like everyone else, I don't know what the problem is and I'm just trying to work out why mine went bad after ~3 weeks of no problems.

http://www.buxbusters.com has identified this as the, or at least a possible, cause.

Having said that, I disabled Wi-Fi Sync last night and this morning it was even worse - only 58% :confused:

Usage stats showed

Usage: 3h 3m
Standby: 6h 38m

even though the phone had not been used since taking it off charge.
Did you disable WiFi sync and press apply to propagate the changes? You can also try to logout of your home wifi network ( 'Forget network' in the wifi settings of your iPhone ). If that works for you you might have the wifi sync drainage bug.

I also update the site with new info, please check it : I found out there is something fishy going on when using wifi-sync and my router -> when using a different DNS entry inside my iPhone the battery drainage would disappear. At least one other user did benefit from this workaround at the moment of me writing this.

Other users reported their battery drain being gone after disabling their 3G data. It seems there are different classes of error behavior with regards to the iPhone 4S battery drainage.

Hope this helps.

Regards.
 

xraytech

macrumors 68030
Mar 24, 2010
2,518
212
For the first few weeks after getting my 4S my battery life was excellent, the suddenly it went bad...

Originally:

Charged to 100% at night, ~95% in the morning, and ~35% when I got home from work

Now:

Charged to 100% at night, ~80% in the morning, and ~20% when I got home from work

Been trying everything, and doing some serious head scratching. Then I realized that the daytime usage was the same - ~60% - for both scenarios so the big drain was only overnight :confused::confused:

At home I have W-Fi, but during the day at work only 2G cellular.

So, it seems to only be a problem when on Wi-Fi :confused:

Finally, I worked out that I didn't enable iTunes Wi-Fi Sync until I'd had the phone a few weeks (it's disabled by default) although I can't be certain that the change in battery drain coincided with enabling iTunes WiFi sync, but it was certainly around that time.

I'm now thinking that my phone is searching for my MBP (which is turned off) all night trying to sync to iTunes. This would explain the big overnight drain.

Tonight I'm going to disable Wi-Fi Sync (has to be done from iTunes) and see if the battery drain rate goes back to how it was.

Does anyone else with poor battery life have Wi-Fi Sync enabled?

I would guess that if you have any Wi-Fi connection then it will try to sync, even if it's not your own home W-Fi - which may explain why some people have really massive battery drain as they may have a Wi-Fi connection at work etc.
Why not just leaving it plugged in over night.
 

Arelunde

macrumors 6502a
Jul 6, 2011
980
28
CA Central Coast
Speaking of weird, sudden changes in battery life, I discovered that DropBox app is a major drain on the battery AND it seems to disrupt normal operations on iDevices and my PC (actually crashed it in conflict with a program) as it searches and checks on items needing sync.

I uninstalled DropBox on all my equipment and everything returned to normal. Go figure.
 

r.apocalypse

macrumors newbie
Nov 11, 2010
2
0
I have an iPhone 4, and I'm on a wifi network on home. I go to sleep and my iPhone have ~70% of battery. I wake up 8 hours after and my iPhone is shut down due no battery at all.

I'm not plugged on power.

If I open my Macbook I see on the itunes that my iPhone is connected, even if I'm not on power, the iPhone is only on the same network and is blocked. Just this could drain all my battery on one night?

My wife macbook and iphone are on the same networks and her Iphone don't drain the battery like mine, the difference is that her mbp is shotdown all night and mine is open and plugged.

There's a way to not connect the iPhone to itunes if it's not plugged or charging on power?
 

Gav2k

macrumors G3
Jul 24, 2009
9,217
1,606
Op have you got fb on your phone?? A lot of users are reporting this issue with the latest fb revision?
 

parish

macrumors 65816
Original poster
Apr 14, 2009
1,082
1
Wilts., UK
Holy thread resurrection Batman!

This thread is 6 months old, my problem was fixed in iOS5.1 :)
 
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