dwill05 wrote:
The phone shuts off the WiFi radio when it goes to sleep to save battery life, not to rack up data charges. It's been going on for quite a while, maybe always, and definitely even during the time of unlimited data. If you want to stop if from dropping the Wifi, leave it on a charger. As long as it's getting external power, it will stay on WiFi, even when asleep.
Unfortunately, it's not really documented anywhere that I know of.
Slightly off-topic on my part, but...is power consumption of data being streamed over 3G significantly greater than over WiFi? I would venture to guess that 3G uses quite a bit of power consumption as well--otherwise there wouldn't be an iOS option that allows you to turn on/off 3G--heck, there is a disclaimer right below the setting that pretty much implies that enabling 3G may decrease battery life...thus implying that power consumption over 3G isn't insignificant by any means.
I reckon there must be some valid reason why Apple decided to make the WiFi radio go to sleep if inactive and the device is not connected to an external power source, but at the same time I would think that it may not be too much to consider providing an option setting to allow users to override it; I mean, the option to enable 3G is already (and still) there...and quite frankly, how many of you folks even use that option (to turn off 3G) at all?
