Under advanced wifi settings one can change number of Wi-Fi channels to be used (11, 13, 14). Does anyone have a clue on how does this property affect battery drain? I know it should be configured depending on how your Wi-Fi router is set-up, but maybe one number of channels should be ("defaultly") preferred over another so battery would last longer?


It has nothing to do with battery life; the number of channels is a regulatory issue (for example, in the US, only 11 channels are allocated for 2.4GHz Wi-Fi).

Technically, Wi-Fi is frequency hopping, so the "channel" is a center frequency around which the actual transmit frequency skips. You can't disable that; it's part of the channel sharing arrangement (Wi-Fi would be unusable if every client on the channel transmitted on the same frequency). And beyond that, which channel your device uses is determined by what AP you're associated with, so you have no control over it.

  • a bit unrelated, but could it be that if lot of devices are connected to a wifi router, they congest the channels and than that is what in the end drains the battery more than it should because more packets have to be re-sent? – pootzko Jun 18 '11 at 15:30
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    @pootzko: that certainly happens, but (a) you still need to change the AP to accomplish anything and (b) adding channels means using someone else's spectrum which is (a) illegal and (b) quite possibly worse (consider what might already be using those addresses; they're not restricted just to annoy people, they're given to someone else). – geekosaur Jun 18 '11 at 16:03
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    Also note that there are additional tradeoffs: a closer AP may be more congested, requiring more transmissions, but may use less power overall than talking to a less congested but more distant AP. (Most WiFi cards do reduce their transmit power when they can; on Linux you can often determine the current transmit power using the wifi tools.) – geekosaur Jun 18 '11 at 16:07
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    @pootzko On a related note: channels 1, 6, and 11 provide the least interference. Wikipedia has a good explanation if you're interested in why. – Matthew Read Jun 18 '11 at 18:32

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