wifi drains 5% of battery per hour in SLEEP MODE

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wifi drains 5% of battery per hour in SLEEP MODE

Last night I went to bed with 50% of battery on my iphone 4. Nothing was on except wifi, no app DLed from app store, autolock in every minute. This morning when i got up the phone was dead and i cant even turn it on. After some observation i found out that with my wifi on, it drains 5% of battery per hour. If i turn wifi off, the battery didn't drop anyting after one hour. Is that a common problem or just me? Do i need to go to apple store to change another one?

thx

iphone 4, iOS 4

Posted on Nov 9, 2010 12:07 PM

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Answer 1

wjosten

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Nov 9, 2010 1:27 PM in response to RiverCrab

What OS is on your phone? Persistent WiFi was removed with iOS 4.1, so if your phone is on iOS 4.0, update your phone.

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Answer 2

RiverCrab Author

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Nov 9, 2010 1:28 PM in response to wjosten

mine is OS 4.1. just bought it last Friday

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Answer 3

wjosten

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Nov 9, 2010 1:32 PM in response to RiverCrab

Possible that an app got stuck on your phone, it happens. Most likely culprit is your mail app. Is your battery life fine now? If so, don't worry about it. However if your battery life is still bad post back.

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Answer 4

Nov 9, 2010 1:38 PM in response to RiverCrab

I bought mine last Tuesday and notice that the battery does drain a little faster than what I thought it should. Please keep us informed.

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Answer 5

RiverCrab Author

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Nov 9, 2010 1:46 PM in response to wjosten

Hi, i've also reboot the program last night and there is no app running in the background. i also double clicked home key to make sure. sadly, wifi is still drains my battery around 5% per hour.

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Answer 6

wjosten

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Nov 9, 2010 1:52 PM in response to RiverCrab

Settings>Mail, Contacts, Calendars>Tap on your Account>For Mail(or anything else listed)>Switch to off. Then, launch your mail app, verify that your account is turned off. Then, reset your phone: Press the sleep/wake button & home button at the same time, keep pressing until you see the Apple logo, then release(ignore the slide to power off). I'm assuming here you're not using any apps that do run in the background, correct?

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Answer 7

RiverCrab Author

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Nov 9, 2010 2:01 PM in response to wjosten

actually i didn't add any accounts for my emails yet. but i'll try set one up and then turn it off and see if there is anything changed. thanks

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Answer 8

wjosten

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Nov 9, 2010 2:08 PM in response to RiverCrab

Your problem is not a stuck mail account, since you've never setup mail. Reset your phone though, this should stop anything running in the background. Turn WiFi off in settings. Monitor your battery usage. If things appear normal, turn WiFi back on. Again, monitor your battery usage.

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Answer 9

RiverCrab Author

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Nov 9, 2010 2:20 PM in response to wjosten

funny thing is that in the usage, the usage and standby shows "-". i've fully charged my iphone like 2 hours ago. even i didn't USE it, at least it should shows the standby time. But it shows nothing now.

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Answer 10

Nov 9, 2010 2:34 PM in response to RiverCrab

RiverCrab wrote:
funny thing is that in the usage, the usage and standby shows "-". i've fully charged my iphone like 2 hours ago. even i didn't USE it, at least it should shows the standby time. But it shows nothing now.

If you reboot the phone it will not show usage until it has been fully charged.

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Answer 11

RiverCrab Author

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Nov 9, 2010 2:40 PM in response to Lawrence Finch

for reboot i mean reinstall the system back to the factory mode

null

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Answer 12

Nov 9, 2010 2:37 PM in response to iPhoneMerc

If you are a moderate to heavy user you will need to charge the phone every night. That is normal. If you cannot get through a day of usage (unless you spend 5-10 hours using it during the day) that is not normal.

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Answer 13

Nov 9, 2010 2:40 PM in response to RiverCrab

RiverCrab wrote:

WiFi doesn't drain anything in Sleep mode because WiFi is turned off in sleep mode. Something else is causing the heavy battery drain.

As you said you don't have any email accounts it isn't email. Safari can drain the battery if left on a page that automatically refreshes.

Location Services can drain the battery - if you see an arrow in the top bar near the right then there is an app running in background and using location services.

Game Center can drain the battery even when it is closed.

Streaming apps, social networking apps (facebook, yahoo, skype, etc) can also drain the battery in sleep mode.

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Answer 14

RiverCrab Author

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Nov 9, 2010 2:43 PM in response to Lawrence Finch

Hi, im not a heavy-user. i just left my phone with wifi on before i went to bed with 50% of battery. then after a 10 hours sleep, my phone's battery is gone. during the time i didn't even touch my phone.

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Answer 15

RiverCrab Author

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Nov 9, 2010 2:46 PM in response to Lawrence Finch

but interesting thing is that when i turn off the wifi, the battery didn't changed even 1% after one hour. im pretty sure that i didn't do any change except turn off the wifi.

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