Friday, December 5, 2008

An Observation on iPhone Battery Life from the Bowels of the Earth

We're teching The Spy at Baruch college, at the Nagelberg Theatre which is on level B3, so somewhere in the earth's mantle, which I can only assume is why the A/C is always cranked so high.  Of course cell service is nonexistant, and since the internal walls are made of generous helpings of concrete, even getting wifi from our production office to the house (probably about 60ft, if crows flew underground through concrete) took two days and two routers to pass the signal so we can get it at the tech tables.  I never quite managed to get it to the booth.


Once I had established our lifeline to the outside world, I kept my iPhone with wifi on and the cell radio off all day (if you don't know how to do this, put it in airplane mode first, then turn wifi back on.) I was expecting that keeping an active wifi connection all day would kill the battery, so much so that I negotiated an electronics deal with Ian, that I would lend him my Macbook 2-prong power adapter if I could charge my phone from his tech table's power, since the power strip on mine was being taken up by frivolous things like the light board, sound computer, and LittleLites.  As it turns out I have never needed to charge it in the middle of the day.

During tech I've been underground for 12-15 hours a day, off the charger for 18 hours or more, and only once did I come home with the 20% battery warning.  Some days the battery was hardly drained at all.  On an average day above ground, using only 3G and maybe a little bit of wifi, I almost always am pushing the limits of the battery by the time I get home. Plus, my commute to Baruch is longer, so the phone spends more time per day playing music.

All of this just to say that I was surprised to find that the wifi radio uses so much less power than the cell radio.

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