General Difference between "blue" and "grey" WiFi/Bluetooth - battery life

Discussion in 'iOS 11' started by f0ku5, Apr 24, 2018.

  1. f0ku5 macrumors member

    Jul 15, 2014
    Hello MacRumors, I have one question that keeps bothering me :)
    Generally I fully understand how the WiFi and Bluetooth buttons are working in control center, but I don't know how it all affects battery life.

    When I'm leaving my home I'm "disabling" WiFi by clicking on icon in control center and this makes my iPhone to disconnect from my home WiFi. I know that WiFi radio is still functional, but does the battery life is better when in "blue" state?

    TL;DR - do I need to disconnect from my WiFi when leaving house by clicking on WiFi button in control center or I should leave it as it is (blue icon)? Is battery life better in one state or another?

    I know that my post is probably a big mess in terms of grammar, but english isn't my native language, please take my apologies :)
  2. C DM macrumors Sandy Bridge

    Oct 17, 2011
    You don't need to disconnect, as you leave the area where the WiFi network works your device will automatically disconnect. Unless you are having some sort of unusual issues with something, you shouldn't really see meaningful battery life difference one way or another.
  3. f0ku5 thread starter macrumors member

    Jul 15, 2014
    Thanks for your reply! I thought that in "blue" state the iPhone is constantly searching for available WiFi networks to join and in "grey" state there's no searching. It isn't true?
  4. Shadow Jolteon macrumors regular

    Shadow Jolteon

    Feb 1, 2018
    United States
    When it is blue, that just means Wifi is enabled. Greyed out means it is disabled. Your phone will always try to connect to any known networks when Wifi is enabled, but won't be trying to find and connect to just any network. It'll search for new nearby networks to connect to while you're in Settings » Wi-Fi. This all likely has an unnoticeable impact on your battery life, in fact, your phone connecting to Wifi could impact it positively, as cellular usually takes more battery life.

    To keep it from searching for new networks constantly when disconnected, you can go to Settings » Wi-Fi and disable the option for "Ask to Join Networks" if it is on. I believe this is disabled by default now, though.
  5. f0ku5 thread starter macrumors member

    Jul 15, 2014
    So there's no need to manually "disable" WiFi when leaving home or Bluetooth after finishing listening via bluetooth headphones and I can just leave them both at blue with no significant drop in battery life when compared to "grey"?
  6. C DM macrumors Sandy Bridge

    Oct 17, 2011
    Not really. That said, if you want, you can use it all for a few days the way you've been doing (where you are disabling things when you want), and then use it for a few days where you just leave them enabled, and then compare to see if there are any noticeable/meaningful differences as far as battery life goes.
  7. f0ku5 thread starter macrumors member

    Jul 15, 2014
    Well, generally I want to just leave them both enabled (blue) 24/7 because WiFi state keeps changing from grey to blue through the day when I'm travelling around city. That really makes me mad :)
  8. Mr_Brightside_@ macrumors 68030


    Sep 23, 2005
    That's because you're leaving Wi-Fi networks.
  9. Chazzle macrumors 68000


    Jul 17, 2015
    No, it’s because Wifi starts allowing new connections (blue) when you travel to a new location. This started with iOS 11.
  10. f0ku5 thread starter macrumors member

    Jul 15, 2014
    Exactly! :)

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