Wifi vs 3G - which uses less power?

[DaveG]

While at home and at work I have Wifi available. Should I expect that turning on WiFi instead of 3G during those times should generally help with battery life?

 

[avengence]

Wifi should take a lot less power but I could be wrong.

 

[DeusInnomen]

Wifi uses significantly less power. Use it as much as you can.

 

[IPvFletch]

Also WiFi on idle uses almost no power at all (it had no real noticable effect on my battery consumption).

 

[Biggest Fro]

Wasn't there an App that switched Wifi on/off depending on your location?

Like, it would turn it on when I am home, but turn it off when I walked out the door

 

[Shawnz]

Wow that's unreal. On my winmo phones / BB wifi was a battery killer. Good to know!

 

[adseguy]

Wif sohuld be fine on when you use it, but experiment a little. When it constantly searches for wi-fi, but doesn't find it....that's bad.

I use Y5 battery saver:

Simply turn the wifi on manually when you are in a zone that you want wifi to be automatically turned on. It registers your cell towers around you so if you walk/drive/bike away from those towers it automatically turns wi-fi off. Pretty simple and smart.

 

[Dangerboy]

M

Wif sohuld be fine on when you use it, but experiment a little. When it constantly searches for wi-fi, but doesn't find it....that's bad.

I use Y5 battery saver:

Simply turn the wifi on manually when you are in a zone that you want wifi to be automatically turned on. It registers your cell towers around you so if you walk/drive/bike away from those towers it automatically turns wi-fi off. Pretty simple and smart.

You can turn off the option of having the evo scanning for networks

 

[adseguy]

Yeah, but it still scans around constantly to see if you have that network available. All that options does is prevent automatic joining to a network that is open.

 

[RiverOfIce]

It really depends on how you use it. Wifi can go into standby when not in use. Which means that battery life is improved. But wifi will suck more battery when in us because of the higher speeds. The one thing people do not understand. The 3g radio must tell the towers where it is so the towers can tell the radio what channel to use. Wifi locks the channel. Which means even in standby, 2 devices can not use the same channel. So 3g has a higher standby power. Bottom line, If you are just using it once in a while and do not need the phone to work, turning off the 3g radio, and using only the wifi wills save battery life. But if you are continuously using the wifi, it will drain more then the 3g radio. The one thing we have not figured out, how to get more speed with less power. The faster the connection, the more power it takes.

 

[DaveG]

Great responses, thanks!

 

[apocalypse_later]

I'm not wholly certain that's true.

In the US wifi is on the ISM channels and generally cannot go past 500mw due to FCC regulations. CDMA technology can go up to 1watt or perhaps even higher. There's a world of difference between CDMA and wifi. Wifi generally will use a fraction of the power for that and other reasons. I have personally verified this with both iPhone and EVO. The cellular modem is always going to draw quite a bit more power, not to mention generally be slower and have huge latencies. You should always use wifi when you can.