3G vs Wifi

[captpg]

I know (or at least I think I know) that wifi is supposed to use less power than 3G. But that's not what I'm seeing on my phone. Using Juiceplotter, with wifi on, I'm cruising through the battery at about 10% or more per hour. Turn off wifi, and it's maybe 2-3% per hour. Usage is about the same, light email and SMS with a little surfing and weather updates.

So I left the phone alone for an hour with wifi on. Mail (Gmail) is set to send/receive every 15 minutes. Battery dropped 10% in the hour. Shut off wifi and left the phone alone again for an hour. Battery dropped 2%. Tried again the next day. Same results.

Does this seem strange? Is there anything that would cause wifi to consume power even when not called to do so by a particular program. Could it (drat!) be a defect in my unit? Any thoughts appreciated!

 

[bigpetefox]

WiFi sends larger data packets than 3G, larger amounts of data= more power output.

 

[captpg]

I don't get it -- then wouldn't wifi generally use more power than 3G? And in my "test", the phone was just sitting there, unused. I can see the radio activity plotted every 15 minutes when just using the data network, but when I switch to wifi, it seems to be "on" full time.

 

[bigpetefox]

I don't get it -- then wouldn't wifi generally use more power than 3G? And in my "test", the phone was just sitting there, unused. I can see the radio activity plotted every 15 minutes when just using the data network, but when I switch to wifi, it seems to be "on" full time.

WiFi uses more power than 3G.

A better way of putting it, let's say you're connected to a 802.11g(54Mbps) wireless connection. If idle, power is constant until data is transferred. EV-DO(burst rate up to 3Mbps) runs with less data, so less data is pushed at once.

 

[rpfarrah]

Yeah, I keep my wifi off most of the time. Only turn it on when I think I need it.

 

[santinelli]

Well yeah think about the 802.11x wasn't written with cell phones in mind, but laptops with big batteries.

Constant polling just for keepalive....

I have NEVER seen wifi use less battery usage than 3g, ever. 3g/4g are 'tuned' for celluar phones and smaller size batteries and optimum battery life...

I was quite surprised when I saw people saying wifi would use less battery than 3g...

 

[novacellx]

Very unusual results. I have the complete opposite happen to me, 3G is a power hungry beast.

While streaming Pandora over 3G I lost 33% of my battery life in about two hours. Compare that to streaming Pandora over Wi-Fi for twelve hours using up ~80% battery life.

Excerpts from my posts earlier in Battery life not lasting? Your fix is in here.

Wi-Fi


13:37:42 Up Time
12:05:23 Awake Time

31% Cell Standby
26% Phone Idle
24% Wi-Fi
10% Mediaserver
07% Android System
02% Display

I estimate that Pandora used 80% of the battery with ~8% for boot, configuration and short periods for monitoring. My final check occurred at 13%, quit Pandora, checked the battery life stats (going down to 12%) and then turned it off.

3G

2:15:47 Up Time
2:15:47 Awake Time

37% Cell Standby
36% Phone Idle
13% Mediaserver
11% Android System
03% Display

Battery life went from 99% to 63% in this period of time. I found there is no need to go the long haul on this test. Under these circumstances, 3G uses up nearly 2.4 times the battery life of Wi-Fi.

I had nice results when the phone was idle for most of last weekend with Wi-Fi on and 3G off, approximately 47 hours up time and 4 hours awake before needing a charge. If I leave 3G on I am finding myself losing nearly 7% an hour, while idle.

 

[doogald]

I agree with others; in my experience, WiFi is less power hungry than 3G. Part of this is that I live in a location with a crappy Verizon Wireless signal, so I bought a Network Extender for phone calls and use WiFi while at home. My battery goes anywhere from 30 to 32 hours in normal use. When I wasn't using WiFi, the phone barely made it until bedtime - about half what I get with WiFi.

You may get different results.