Wi-Fi or 3G?

[jimfreeman]

When both a Wi-Fi and 3G network are available, does the Droid default to one or the other? Is this function user-selectable, other than turning off Wi-Fi? How can the user tell which network is being used?

[dfuser10332]

When both a Wi-Fi and 3G network are available, does the Droid default to one or the other? Is this function user-selectable, other than turning off Wi-Fi? How can the user tell which network is being used?

You should see a 3G symbol when not using wifi. Wifi will give you a "beacon" symble. If you have your phone set for wifi and leave the area it will default back to 3G. Wifi is user established.

[zero7404]

when wifi is on, that is the preferred connection. when you drop out of range from your wifi network, it switches to 3G. i just wish android had a solid connection for wpa2-aes encrypted networks....wifi is faster than 3G.....

[JRogers1978]

Any idea as to which one uses more battery?

[Merire]

Wifi uses way more battery.

[JRogers1978]

Wifi uses way more battery.

That's what I was afraid of. Thanks!

[dylanthecat]

Wifi uses way more battery.

I have to disagree. I have WIFI always on and in never sleep mode. When at home I am on WIFI and when I get to work it switches again to WIFI. I am only on 3G when in other places. Running this way uses less battery than without WIFI, and the speed is much faster.

[Fraxinus]

Wifi uses way more battery.

This is correct, there is just a little more to it than that. I've been watching bits and pieces of this video (Google I/O - Coding for Life -- Battery Life, That Is) on Google IO (very informative!). You can also download a PDF of the presentation from there. This is taken straight from Jeff Sharkey's slides:

What costs the most?
Bulk data transfer such as a 6MB song:

• EDGE (90kbps): 300mA * 9.1 min = 45 mAh
• 3G (300kbps): 210mA * 2.7 min = 9.5 mAh
• WiFi (1Mbps): 330mA * 48 sec = 4.4 mAh

So it really depends on what you are doing. For massive data transfer, your'e actually better off with WiFi. Even though it consumes more amperage to run, it won't operate as long to transfer the same amount of data, thus saving battery life.

[dylanthecat]

Interesting figures. I would also add that it depends on the strength of the signal, be it wifi or 3g. In my situation I have good wifi and 3g home and work. My download speed is around 6-7Mbps home and work on the droid, and 3G is about 1.5 to 1.7 Mbps. Therefore according to your numbers, for me wifi is even more of a battery savings.

[Fraxinus]

I would also add that it depends on the strength of the signal, be it wifi or 3g.

Great point. Cellphone wireless radios in general will ramp up their power output in the presence of a weak signal, consuming more power (and exposing you to more RADs too).