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Comment by aggronn | Hacker News Reader

I almost never use wi-fi on my phone. It drains the battery too much.

edit: I'm not familiar with cellular hardware tech. My observation is true for my phone, necessarily, because my 3G reciever is active 100% of the time, and turning on wifi is just turning on another component. If this isn't the case for you, do you turn off your 3/4G while you're in a wifi spot? Does it manager this all automatically?

Do you have your wifi on while you're outside of a wifi spot? If so, how does that not cause a loss in battery life over never having it on?

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Unfortunately I almost never use cellular data on my phone. It drains my bank account too much.

It seems to me to actually be the opposite. Having a working wifi connection will increase my battery-life by at least a factor of 2

The cost of charging an iPhone 3G for AN ENTIRE YEAR is about 25 cents.

(Source: Electric Power Research Institute http://bit.ly/NV287P).

Granted, they charged it every other day but with even the heaviest Wi-Fi use, you couldn't more than quadruple it, which still leaves you at an inconsequential $2 a year.

My problem isn't the cost, its that I have a battery so I can be mobile--which means I can't recharge it just because the battery gets low.

I wish the new 802.11 ac standard would've gone the "battery efficiency" route, rather than doubling the performance. Technically, they could choose either doubling the performance or cutting the power consumption in half, but I'm pretty sure they will go the performance route, which really isn't necessary on a mobile phone right now (500+ Mbps).

802.11ac improves range and performance, but the new Bluetooth specs improve range and battery power.

If you mean Bluetooth 4.0, its bandwidth is like 50kbps IIRC. It can't be used for anything other than heartbeat monitors and stuff like that.

I know absolutely nothing about Bluetooth, but I watched a WWDC 2012 video about it just for fun. It was an extremely well-done introduction to this technology.

Session 703, Core Bluetooth 101 - https://developer.apple.com/videos/wwdc/2012/ (requires a free developer account)

Bluetooth runs at ~2 Mbps which is not too shabby. And there's a new (as of BT 3.0) "high-speed" mode which actually sends bluetooth traffic over 802.11, so you can keep your wifi radio off until you actually need to send a lot of data.

edit: I haven't watched your video yet, but thanks for the link :)

Sorry, I thought you were talking about Bluetooth 4.0, which is very low-power and very slow.

These two slides are from the aforementioned talk. Note that 'Classic' means 3.0 and 'Low power' means 4.0:

http://d.pr/i/cRvm

http://d.pr/i/qCHB

Well 4.0 includes "classic" and the new low-power mode. But I see on Wikipedia that BT has a 3 Mbps mode (aside from the 802.11 "high-speed" mode), do you know what that would refer to?

That seems unlikely. WiFi should certainly drain your battery less than cellular. (I have yet to jump on the smartphone train but my iPad gets consistent 7 hours with 3G, 10 hours with WiFi.)

WiFi also kills my phone's battery.

It appears that for newer devices, wifi uses a lot less power.

There is, however, a cost in searching for WiFi networks every time you want to make a connection.

I imagine it becomes most apparent if your device is polling for email. On every interval it needs to wake up, turn on WiFi, look for any available networks, discover there are none and then finally revert to the cellular network. With WiFi disabled, it can go straight to cell.

The iPhones were famously bad for this in the early days, though they seem to improve later on; either through a hardware or software update, I'm not sure which.

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