Wifi on lock responsible for dramatic battery drain

Discussion in 'iPod touch' started by GoodBoy, Sep 23, 2010.

  1. GoodBoy macrumors 6502

    Nov 17, 2007
    Ok, so there alre already a few threads about battery problem. Unfortunetley most of them misleading - some of them suggesting battery drains fast because of the multitasking. It is not true.

    First of all multitasking isn't responissible for battery drainage, as it is not real multitasking - apps doesn't run on background, so they can't drain battery). Second of all, wifi is to bo blame. On previous iOS firmwares wifi was automatically OFF whenever the device was locked. Since iOS 4.0 wifi stays ON all the time, even when you lock your iPod touch. This causes dramatic battery drain, as it is constantly communicating with servers. My iPod touch 3rd gen 32gb drains about 30-50% of battery overnight when locked with wifi ON. Yesterday I did some different test - set wifi to OFF for the whole night and guess what battery percentage didn't drop by even 1%! Regardless of how many apps were opened in multitasking.

    Concluion is - Apple neeeds to go back to shutting wifi OFF when device is locked - or at least give this as an option switch in the menu.
  2. burgundyyears macrumors 6502

    Sep 3, 2010
    You have an app keeping the wifi on in the background, like a VOIP service or something. I have no problems with the battery (last charge just lasted 4 days) and I don't turn the wifi off manually.
  3. GoodBoy thread starter macrumors 6502

    Nov 17, 2007
    Sorry, this isn't the case, since 1) multitasking in all iOS devices doen't technically work in background - apps are only saved in flash memory on it's last state of operation, 2) I had a test without any apps on hold in multitasking and battery drained either, when wifi set ON in lock.
  4. sracer macrumors 604


    Apr 9, 2010
    in exile
    That's not entirely true. Multitasking on iOS4 DOES allow some specific processes (APIs) with the app to run in the background. If an app doesn't use any of those particular APIs then it won't multitask at all. But some apps, like Skype use those APIs and so iOS will allow those particular elements of the app to run in the background.
  5. lanulos macrumors regular

    Jun 19, 2010
    Is there a Cydia app for jailbroken iPods that will turn WiFi off automatically on lock? That would be a good app for someone to write, if there isn't one already.
  6. burgundyyears macrumors 6502

    Sep 3, 2010
    In iOS4, apps using certain APIs do remain active and running in the background. Apps using the VOIP and background audio APIs are examples of this. The first day I had the touch, I kept Skype running and it drained my battery by the end of the day. I quit its process and have never had another battery issue.
  7. GoodBoy thread starter macrumors 6502

    Nov 17, 2007
    Ok, you're right guys I admit there are some apps that actually work in background, but like I said battery drains on lock (with wifi ON) even without a single app in multitasking. Don't know what's going on, maybe iPod is communicating with routers to maintain constant connection with Internet? I rememeber on 3.1.3 firmware whenever I unlocked my iPod wifi took a moment to reconnect with internet again. With 4.1 when unlocking, wifi is instantly ON, no waiting for connection. So maybe this is the casue for battery problems.

    An idea for Cydia app to shut wifi off when locked would be a good solution, but I think Apple should come out with it's own salvation for this.
  8. keigo macrumors regular

    Nov 6, 2006
    and then when apple turn the wifi off when lock we will hear the complain of..

    my skype wont work when the device auto lock...

    or my internet radio stop awhile later after the device auto lock...

    how can I keep the wifi on when device is lock etcs and we are back to square 1.
  9. dave1812dave macrumors 6502a

    May 15, 2009
    I have 4.1 on a 4g and 2G touch---NO problems with battery drains. It's only some people's devices that are having that issue. good luck.

    I also have a touch with 3.1.3. there's NO difference in battery life between the 3 devices/
  10. steve1711 macrumors newbie

    Nov 21, 2009
    No battery drain

    I have zero battery drain overnight if I leave wifi on. Doesn't matter how many apps are in the background. 100% charge at night and 100% charge 12 hours later. It must be a problem with only some machines.

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