Wifi vs 3G

[WLF218]

I usually use wifi at home on my iPhone 4s. Sometimes, though, everything goes real slow over wifi (at certain times of the day something seems to interfere with our wifi - even on the computer). When that happens I switch my phone to 3G and everything goes much faster. I use my phone a lot and am always trying to conserve battery life. I can't seem to find an answer: does using 3G drain the battery faster than using wifi? Or does it make no difference? Thank you.

[Ads]

[Skull One]

Yes, 3G uses more battery than WiFi. While I can't say exactly how much on the iPhone because they don't expose enough information, when I ran my tests in Android 3G used 36% more power than WiFi.

[iHolophyte]

Yes, 3G uses more battery than WiFi. While I can't say exactly how much on the iPhone because they don't expose enough information, when I ran my tests in Android 3G used 36% more power than WiFi.

Does it really?
Whys that? Pulling in more power presumably for 3G services?


iHolophyte

[Skull One]

3G uses a radio that has to transmit between .25 and 1 watt depending on several factors such as line of sight, distance, frequency and materials being penetrated. That power is way above WiFi usage. WiFi can only broadcast to a range of a few thousand feet legally. 3G can transmit past 5 miles. Since most people have the WiFi station within a few hundred feet, you only need about 1/4th the power of 3G for sustained data transfer.

[maka]

wrong... remember that on the iphone 4s you do not have the option to turn off 3g. So when your connected to wifi your phone still have 3g service running in the background so your using twice as much battery consumption. I know for a fact because Im home most of the day and on wifi and my battery drains fast when im not even on it.

[Skull One]

wrong... remember that on the iphone 4s you do not have the option to turn off 3g. So when your connected to wifi your phone still have 3g service running in the background so your using twice as much battery consumption. I know for a fact because Im home most of the day and on wifi and my battery drains fast when im not even on it.

How to clear up your misconception and very bad information you have derived from your observed fact.

1) I specifically stated "sustained data transfer". Which is key to the persons question and makes my answer 100% spot on.

2) Your iPhone is probably in a bad reception area and is constantly upping the power needed to stay in contact with the cell tower. This has NOTHING to do with 3G data. This feature is in EVERY cell phone ever made. And is your culprit for battery drain. And you can look that fact up.

[prawns]

Estimated battery Life according to my Battery App on a iPhone4 (with a 100% charge)

Standby = 300hours

Internet Browsing
WIFI = 9hours 4minutes
3G = 8hours 9 minutes


Talk Time
2G = 14 hours
3G =7 hours

For other stuff if your curious
2d Games = 3hours 37mins
3d Games = 2hours 16mins
Reading = 13 hours 36mins
GPS navigating = 1hour 48mins
Video Chat = 2hours 51mins
Photo Takeing = 6hours 21mins
Video Recording =3hours 37mins

[Skull One]

Estimated battery Life according to my Battery App on a iPhone4 (with a 100% charge)

Standby = 300hours

Internet Browsing
WIFI = 9hours 4minutes
3G = 8hours 9 minutes


Talk Time
2G = 14 hours
3G =7 hours

For other stuff if your curious
2d Games = 3hours 37mins
3d Games = 2hours 16mins
Reading = 13 hours 36mins
GPS navigating = 1hour 48mins
Video Chat = 2hours 51mins
Photo Takeing = 6hours 21mins
Video Recording =3hours 37mins

Those numbers are from Apple's published data and are done under optimal conditions. IE their standby time is wrong if you compare it to 50% of the iPhone 4 users out there. Because standby is affected by several factors with the biggest being the dBm loss and subsequent power increase on the cell radio to maintain contact with the cell tower.

[prawns]

yep tell me about it - Im in a fringe reception area and my phone is constantly fighting for a cell signal which affects my battery life

From apple webpage on tips to save battery:
"Turn off Wi-Fi: If you rarely use Wi-Fi, you can turn it off to save power. Go to Settings > Wi-Fi and set Wi-Fi to Off. Note that if you frequently use your iPhone to browse the web, battery life may be improved by using Wi-Fi instead of cellular data networks."

Tends to agree with you mate - Cell signal uses more battery than a WIFI signal according to apple as well - and I definatly agree on your cell signal affecting battery life as well (mine keeps losing and reaquiring a cell signal at home and this seems to use alot more battery with it constantly struggling - i get better battery life at work where I have a good cell signal and its not dropping out intermittently)

Like you say - I aint getting nowhere near 300hours standby (thats a laughable stat I think for me at least - theoretical calculations based on optimal conditiions I bet)

[Skull One]

From apple webpage on tips to save battery:
"Turn off Wi-Fi: If you rarely use Wi-Fi, you can turn it off to save power.

The only reason they post that is due to one VERY SMALL reason. Every time you come out of standby, the very first thing the iPhone does is spin up the WiFi chip and search for any known routers. That power draw is measurable and if you come out of standby say 50 times in a day without hitting a known router it can add up for no payout in 3G savings later on.