Sunday, June 20, 2010

iOS4 vs iPod Touch Battery Life

With the release of iOS4, my iPod Touch (2G) gained the ability to remain connected to Wi-Fi even when locked or in sleep mode to receive push notifications (or VoIP calls in the background).  The implications for battery life however are not immediately apparent.

Having lived with iOS4 on my iPod Touch since WWDC, I was initially caught off guard by the significantly reduced battery life.  Previously my iPod Touch could go about a week without recharging, as I used it mostly for listening to audio an hour or so a day, and occasionally for looking up other information.  After installing iOS4, battery life dropped to a couple days, or even less depending on the application I was in.

It turns out the WWDC application needed to be updated for iOS4 to conserve battery life, but more importantly, it had enabled "Notifications", the 3rd item under Settings.  With notifications enabled, an iPod Touch will stay connected to a Wi-Fi network even while in sleep mode, thus burning through the battery much faster than I had previously experienced.

If you use an iPod Touch mostly as a music player and don't normally need notifications, be sure to leave this turned off in the Settings application, or select Airplane mode when you don't want the radios to remain active.


- Peter


Update 6/28/2010

Several users report their battery is still being drained while their iPod Touch 2G is sleeping.  I believe this means other applications are activating the radio.  Since the iPod Touch 2G doesn't officially get "multi-tasking" even with iOS4, this means one or more of Apple's built-in applications which are authorized to run in the background are implicated.  I see two solutions so far:

(1) Use Airplane mode to explicitly prevent the radios from powering on.

(2) Review your iPod Touch Settings and disable any background network access.

Settings -> Notifications = Off

Settings -> Mail, Contacts, Calendars -> Fetch New Data -> Push = Off

Settings -> Mail, Contacts, Calendars -> Calendars -> New Invitation Alerts = Off

Settings -> WiFi -> Ask to Join Networks = Off

I hope Apple adjusts the default settings or provides an option to restrict network access while the iPod Touch is locked so unsuspecting iPod Touch users are not left to resolve battery life issues on their own.


  1. I've noticed that my battery on the iPod touch has been lasting less than a day since the upgrade to ios4 so will try the notifications although think these were switched on before. I'll keep looking and trying

  2. I have a 2G Touch with iOS4 installed 3 days ago... battery life is now maybe a 3-4 times shorter than on 2.2.1 and there is no "Notifications" thing under Sattings. On 2.2.1 the device had the push mail enabled and was receiving mail every now and then.

  3. I am having the same problem -- I turned notifications off, but I had it on with the previous operating system with no problem. I think that there is a bug in this os.

  4. It is the same for me... I'm a bit surprised because I wouldn't think the new features result in such lower battery life. I hope there will be a patch for this soon... it is very strange at least for me..

  5. After upgrading my iPod Touch 2G from 3.1.3 to iOS4 my battery life has been plummeting over the course of a day with extremely minimal usage.
    When I went to bed it had a fully charged battery, and in the morning it was down to 20%.
    I've now disabled notifications and certainly hope this fixes it.

    I heard an iOS update is about to be released, so that may help too.

  6. Battery life is back to normal now, so turning notifications off fixed it for me.

  7. I've had similar problems with my iPod. Turning off notifications didn't fix the problem, but resetting the network settings did. I had the same great battery life I used to have, until a few days ago that is. It's starting to do the same thing again. The only differences is that I've added some wireless networks to the iPod for it to automatically connect to; this has got to be a bug.

  8. Disabled notifications and set mail and calendar updates from Push every 15 minutes to Fetch hourly. We'll see if my wife starts to experience better battery life on her 2G.

  9. I noticed battery life going from a week to a day like others here. I hope these fixes work and I must say, shame on Apple for these battery problems. I was looking at sending my iPod in for a new battery!

  10. Tried all the suggestions to turn off notifications, turn off push, etc. Finally, the setting that restored the battery life to the same as under 2.2.1 was turning on airplane mode. It's kind of sad, because now, the autosync via MobileMe will not be so automatic anymore. Life was better under 2.2.1.

  11. With my iPod 2G, I have to switch to airplane mode to get reasonable battery life. It seems like iOS4 really is the Vista of the iiDevice world. Sluggish, drains the battery, apps crash spontaneously. Yuck.

  12. After having tried the other earlier suggestions, with no noticable improvement, resetting the network settings fixed the problem for me. Thanks for the tip, Carl. I'm also using the airplane mode when only listening to music, just in case.

  13. And does anyone know if this is being addressed by Apple? Hmmm, this sounds suspiciously like some of the blogs and problems I've read about Microsoft... the same brother from another mother?

  14. As an iPod Touch 4g 64 user- I didn't have the option to downgrade to iOS2 or 3... iOS4.0/4.1 is native to 4g ipod touches- we cant downgrade- or the warranty is void....
    I'd gotten a replacement from the Apple Store- and the replacement was the same- battery charged up all night and dead by lunchtime- with the unit off!
    Returned it- and waiting now day 5 for my cash to be returned to me- they refused to give me cash for my return- when I gave them cash when I bought the thing.
    Apple is a bitter barrel of laughs for this new customer.
    I don't think I'll ever buy another product from them. They still have my $430.92 -iUnbelievable/iLame