Apple Watch battery drain on iPhone?

Discussion in 'Apple Watch' started by shr631, Mar 28, 2015.

  1. shr631 macrumors regular

    Dec 13, 2013
    How significantly will the watch impact the battery of the iPhone due to Bluetooth/wifi?
  2. walshy1009 macrumors regular


    Dec 27, 2012
    Victoria, Australia
    Defiantly have your AW & iPhone paired via WiFi when you can to save battery life. Personally, I have Bluetooth turned off as much as possible as for me, it's a battery drainer (even on standby)

    When you're out and about, then pairing via Bluetooth will be your only option of course but if you're at home or even at school if you've managed to hack into your schools WiFi, turn Bluetooth off and pair on WiFi when possible.
  3. 8CoreWhore macrumors 68020


    Jan 17, 2008
    Big D
    The screen on the iPhone uses more battery than anything. So the fact that you'll be turning it on and off less, but instead, referring to the Watch for notifications, etc, will save battery life on the iPhone.
  4. FlatCable macrumors member

    Mar 17, 2015

    BT uses so little power it's ridiculous to disable it for just the sake.
  5. walshy1009 macrumors regular


    Dec 27, 2012
    Victoria, Australia
    I did my own test a while back with my iPhone 5S

    Test 1 (Day 1) was with Bluetooth On but Bluetooth wasn't connected to anything

    Test 2 (Day 2) was with Bluetooth Off

    On both days, I logged my battery life every few hours and when I finished all my testing, I found out that I had more battery life at the end of the day when Bluetooth was turned off.

    May vary from device to device but that's the results I gathered from my own tests.
  6. FlatCable macrumors member

    Mar 17, 2015
    So, you just turned bluetooth on/off, and that's it?

    That's completely ridiculous.

    There are hundreds of factors that can affect battery life.

    It's not a controlled test.
  7. NAYo2002 macrumors 6502

    Apr 16, 2011
    I have mine paired to my Fitbit Charge for past couple of months. No noticable difference. Trying to watch a video for a couple of minutes in a low signal area drains phone battery more than all day of Bluetooth usage.
  8. zacheryjensen macrumors 6502a


    May 11, 2009
    It's connecting with BT LE, it won't be much of a drain at all. I use a number BT LE items and they hardly use any power. They also have far shorter ranges, too. That is where the power is saved, primarily. Less radio amplification.

    I don't think it's going to be a significant drain on the iPhone.
  9. Runt888 macrumors 6502a

    Nov 17, 2008
    This is incorrect advice. Bluetooth uses less power than wifi. Also, the watch won't connect to a wireless network.
  10. Runt888 macrumors 6502a

    Nov 17, 2008
    It's very possible, based on usage, that you will get better battery life since you will be unlocking your phone and turning on the screen less often.
  11. Vundu macrumors 65816


    Jun 10, 2009
    Manchester, UK
    Has quite a hit on my battery life if I leave it on all day.


    Thought it can when the watch and phone are on the same network? They said something about it so you can leave your phone in one room of the house and still receive stuff on your watch.
  12. largefarrva macrumors 6502a

    Jun 30, 2012
    Even if it's possible to connect the two devices together via wifi like mentioned here...are you really going to want to bother with switching between a bluetooth and wifi connection multiple times a day every day you leave the house? It would get old in a hurry.

    As already stated, just leave bluetooth on because while it does drain the battery a's not all that much. I would venture to say that the difference between a full day of leaving it on and off might be 5% at most these days. Today's bluetooth isn't like bluetooth 10 years ago.

    There's plenty of days that my phone by the end of the day reads 85% and that's after pulling it off the charger at 4:30am. I've been using bluetooth on my phone and leaving it on for several years now (since 2011)...started when I bought a vehicle that I could connect to it's stereo system via bluetooth and I haven't looked back. I thought back then it would kill my battery too, until I actually tried it out and realized that it didn't make any noticeable difference.

    So to summarize....leave the bluetooth on. It's not going to kill your battery.
  13. Runt888 macrumors 6502a

    Nov 17, 2008
    The watch will connect directly to the phone using wifi. During the keynote he just used home as an example of one place you might not want to carry your phone with you. It will do the same thing at work, or the gym, or out in the middle of the woods - no wifi network required.
  14. Domino8282 macrumors 6502a


    Apr 22, 2010
    Southeast USA
    There seems to be a lot of confusion about this feature. I have seen it argued about in multiple threads, and so far the only source anyone has cited as evidence is 1-2 sentences from the keynote which were somewhat vague.

    Does anyone have a definitive explanation of how the WiFi pairing works?
  15. Mr.C macrumors 601

    Apr 3, 2011
    London, UK.
    There must be a fault with your 5S then. I use to have a 5S before I got my 6 Plus and I've had the Pebble since it launched. With both phones with the Bluetooth on all the time in order to communicate with the Pebble the reduction in charge has been no different then with the Bluetooth off. Bluetooth especially the latest version is inherently a low power connection and uses hardly and charge.
  16. hemolyzer macrumors member

    Mar 10, 2015
    BT barely uses any energy and you're not going to be turning your phone screen on dozens of times a day due to the watch so your phone battery life will actually be better.
  17. Mr.C macrumors 601

    Apr 3, 2011
    London, UK.
    True. If anything my phone battery life has been better because I have a Pebble. I turn my phone on a lot less because of it. If I get a notification I'm not interested in and want to dismiss it I just do it on my Pebble.
  18. Runt888 macrumors 6502a

    Nov 17, 2008
    There is nothing definitive yet, but it's based on several things:
    1. After the first unveiling, journalist were told that the watch had wifi, but it was only for connecting to the phone, not the Internet.
    2. The page at says it uses bluetooth and wifi for seamlessly connecting to an iPhone. There's absolutely no way to make the process absolutely seamless with all of the different router configurations out there (even if the watch gets login info from the phone).
    3. Apple already uses direct wifi connections for things like AirPlay and AirDrop.
    4. Apple has been very careful about how they talk about the wifi (ie, When Kevin Lynch was talking about it, he was very careful to only say that wifi is used to extend the range of bluetooth). If it could connect to a router than Apple would just say it has wifi and be done with it.
    5. My personal theory - there's no way to get full wifi on the watch without killing the battery, but by restricting it to communicating just to the iPhone they can use it sparingly and maintain decent battery life.
  19. ksuyen macrumors 6502a


    Jun 26, 2012
    Hi Runt

    Yes, we have discussed this at length. While nothing is conclusive, it is definitive that the Watch can connect to the iPhone via wifi. What does it mean to battery life, how extensive is the Wifi connection and how does it work, no one knows until the Watch release and someone does a test.
  20. technosix macrumors 6502a

    Jan 13, 2015
    West Coast USA
    As the launch arrives and watches are put into service I bet that the battery complaints will be very lively. Battery threads are always an element that gets a lot of attention.
  21. nathanjbrown macrumors 6502

    Apr 9, 2008
    Boston, MA
    There's absolutely no way the Watch will connect DIRECTLY to your iPhone via wifi. Why? Because your iPhone can only connect to a single wifi network at a time. Establishing an ad-hoc network with the Watch would then prevent the iPhone from connecting to any other wifi network and, thusly, disconnect it from the Internet.

    I know this has been debated, but it's really quite simple. The Apple Watch will follow the rules of wifi. It will connect to an iPhone via an established network (read: router) and it will NOT have direct access to the web because Apple wants to be sure Apple Watch customers are also Apple iPhone customers.

    And if you disagree, please stop to ponder how many times you've connected your iPhone to TWO wifi networks AT THE SAME TIME and transferred data across those two networks simultaneously.
  22. MeFromHere macrumors 6502

    Oct 11, 2012
    The WiFi hardware in the phone could set up a connection point for the Watch, and still maintain its connection to a regular WiFi network -- as long as Apple provides the software. I guess if Apple finds a compelling reason, they will provide the software.
  23. Esoom macrumors 6502


    Apr 30, 2010
    Been using a Pebble for a couple of months, since it cuts my phone screen time down, I get better battery life paired to and using the Pebble.
  24. Runt888 macrumors 6502a

    Nov 17, 2008
    Wrong - Apple already does peer to peer wifi while connected to a wifi network. See Just because you've never deliberately done it doesn't mean it can't be done. Please don't spread misinformation.
  25. FlatCable macrumors member

    Mar 17, 2015
    Apple Multipeer Framework.

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