Battery Life - 8 possible explanations

Discussion in 'iPhone' started by firewood, Jul 13, 2008.

  1. firewood macrumors 604

    Jul 29, 2003
    Silicon Valley
    1. Battery gauge accuracy out-of-the-box. Your battery gauge will not have been calibrated until you've done 2 or 3 complete charge/discharge cycles (100% to 0%). Until calibrated, it might be reporting 20% when there's a lot more run time left in the battery. (But don't deep cycle calibrate too often as this will shorten the battery life).

    2. Active Data and Voice usage. Apple engineers have said that this is the activity that drains the battery at the highest rate.

    3. Application use. One guess is that battery life under continuous (non-game, non-network) use is only about 6 to 8 hours. Games that use the graphics chip may drain the battery even faster. Applications that use the network will drain the battery even faster.

    4. 3G cell tower proximity. If you are far from a 3G tower, or don't get many bars, the iPhone transmitter power will get turned up. This can consume a lot of power, both in standby and when used for voice/data. Try testing in two different locations known to be near/far from a 3G cell phone tower. (How does one determine that?) Or if you are near an EDGE tower, try turning 3G off.

    5. Backlight Brightness (in Settings) : Please report your backlight brightness. This makes a big difference in battery life on other handheld devices.

    6. Push Data: (suspected) Has anyone actually measured the difference in standby battery life (after after calibration) of keeping Push data ON/OFF?

    7. Location Services: (suspected) Has anyone actually measured the difference in standby battery life (after battery calibration) of keeping the GPS chip ON/OFF?

    8. wifi: (suspected) Has anyone actually measured the difference in standby battery life (after battery calibration) of keeping wifi ON/OFF? Also, wifi power usage will vary with distance from the access point. Try turning wifi off if you aren't getting any usable wifi bars, else the iPhone will just waste power trying to connect.
  2. Pobtastic macrumors newbie

    Jul 15, 2008
    Okay I can debunk a few of these suggestions as I've upgraded my original 8Gb iPhone to the 2.0 firmware and whereas it used to hold a charge for several days, last night when left off the dock it had a flat battery in the morning... Therefore;

    1 is possibly incorrect - as it certainly is battery life that's being affected not just the gauge. If this was only a problem with new 3G phones then yes, perhaps it could possibly be a point, but I've had this iPhone since the first day they released them.

    2 is undoubtedly incorrect - I was asleep and well, I've slept before (trust me on this, I *do* sleep) and used perhaps only 5%-10% battery life overnight, never 98% before...

    3 again undoubtedly incorrect, I was asleep therefore no application use. However... I do have the AIM app installed and I didn't have the setting to 'auto-sign-out-on-exit' on, so perhaps this app is backgrounded and was perhaps on all night? I haven't run it since I first installed it though (no reason to) and the phone has crashed many times and restarted since then so I doubt the AIM app was actually running at all? In case you're wondering about the crashes, I keep forgetting that if you run 'Vicinity' whilst listening to music, the whole phone crashes quite spectacularly...

    4 this has affected my non-3g iPhone, so it's more a firmware update/ new features problem than specific to new model iPhones.

    5 I've not changed any brightness settings on my iPhone since I've had it and only now am I having battery life issues. This isn't relevant.

    6 I've turned PUSH off this morning, I suspect that an 'always-on' PUSH service is probably responsible for the rapid charge loss. Time will tell...

    7 Irrelevant - again this isn't specific to new model iPhones.

    8 Irrelevant - my iPhone *used* to be fine, I've changed nothing.

    So from all those points, you can deduce that's it's either PUSH or backgrounded apps. I'm suspecting PUSH, but you can't rule out backgrounded apps either...

  3. spinalman macrumors newbie

    Jun 21, 2008
    That all makes sense... good post. Certainly by my 4th day of use has seen improved battery life.
  4. marksman macrumors 603


    Jun 4, 2007
    I did notice the second day of heavy usage when I had it down to like 20% sooner then expected, I ran it for a very long time without it ever running out.

    I finally put it on a charge and went to bed.
  5. nomad01 macrumors 68000


    Aug 1, 2005
    Birmingham, England
    Although my battery life has increased immensely since the first charge. It was on charge overnight on Friday and then Saturday it died within about 7 hours most of which was on standby.

    Since then, it's lasting MUCH longer so the batteries gauge could be an issue.
  6. sadsack macrumors member

    Mar 6, 2008
    GPS and Battery Life

    Question for you all, if you leave location services on and then exit out of google maps does GPS stay on? My assumption is that it will stay on, however, i am hearing that if you exit the application it stops using it. Can anyone clarify?

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