Battery life equivelency

Discussion in 'iPhone' started by chinl, Jul 31, 2008.

  1. chinl macrumors member

    Jul 20, 2008
    Given the plethora of battery life related threads I thought I would post a somewhat mathematical explanation, or at least estimation of the issue.

    Apple claims 300 hours of standby on their website. There are other values for different activities. Based on their specs it would be the following conversion:

    1 hour edge phone = 30 hours standby
    1 hour 3g phone = 60 hours standby
    1 hour 3g data = 60 hours standby
    1 hour wifi data = 50 hours standby
    1 hour video = 42.9 hours standby
    1 hour audio = 12.5 hours standby

    So if you were to talk for an hour (3g), surf an hour on 3g, and another two hours on wifi after listening to 2 hours of music you should expect:

    300 - 60(1) - 60(1) - 50(2) - 12.5(2) = 55 hours of standby left, which is two days. But remember that your total 6 hours of usage need to be spread over the two days, so it is really about 3 hours of use per day of standby.

    Games may use significantly more power than any other application as well -- Apple has no way of predicting what an app uses in terms of resources.

    Downloading a video and then playing it will use more power than playing one stored locally. As will streaming music versus using the iPod.

    I don't know how they measure Internet usage, but the power use depends on how much gets downloaded. If you download plain text and read it for a long time it will last orders of magnitude longer than streaming video from Youtube constantly. Streaming online video might be more like 100+ hours of standby per hour equivalent as it is playing video and uses the internet constantly. Browsing average sites will fall in the middle (probably their estimate).

    Other factors like signal strength will affect the battery and are out of your control. Screen brightness sucks up power. High speaker volume uses more energy. Location services really doen't matter too much except for when they are in use. The device doesn't constantly hold a GPS fix unless asked by an app.
  2. andyblila macrumors 65816


    Jul 8, 2008
    On My iPhone, or my iPad?

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