What actually uses more battery power - WiFi or 3G ?

In my experience with everything being equal - full or a strong wi-fi connection/reception and full or strong 3G reception, actively accessing the internet via 3G will consume more battery than actively accessing the internet via wi-fi. When 3G reception is low or lower, more battery will be used.

I rarely turn wi-fi access off.

without a doubt 3g burns more battery than wifi

If you try something like "Battery Magic" or any one of the dozen or so battery tracking apps in the app store, they will predict about twice as much wifi internet time as 3g internet time for any given charge remaining.

I've had the same experience (3g using more battery than wifi) I've noticed that persistent programs, such as instant messaging programs, tend to use about equally regardless of connection type, but maybe this has to do with the bulk of said battery usage being program and not internet.

Be nice if an engineering type would give some specific figures. But I seem to remember that a wifi transceiver is running in the couple-of-hundred milliwatt power range, while a 3G cell phone is something like 0.5-1.0 watts, so it only makes sense that using the cell phone radio would drain the battery much faster.

Actively accessing the internet via 3G will consume more battery than when actively accessing the internet via wi-fi - in my experience anyway using a 3G for over a year now.

Yes, I know. Googlin' for it, I found reports that a typical wifi transceiver is in the 100-200 millliwatt range, and a cell phone radio can be up to 1.0 watts (500 to 1000 milliwatts), so the 3g radio is using 2.5x - 5x as much power as the wifi.

it's the opposite.. WiFi uses LESS power.. as the above posts suggest..

Quoted from http://www.apple.com/iphone/specs.html


+Internet use:+
+* Up to 5 hours on 3G+
+* Up to 9 hours on Wi-Fi+