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Battery Life in Smartwatch Mode

Former Member
Former Member over 5 years ago
Hi, I just bought the Forerunner 945 and used it over the last couple of days. While it is a great watch, I am a bit underwhelmed about the battery life. It should last up to two weeks in Smartwatch Mode but it seems to use 12-14% per day with little usage which would just give me half of that (this is without doing exercises...as said, minimal usage, which is checking pulse from time to time or reading an incoming msg). I have mostly just factory settings on. I also already checked the tipps on the garmin side of how to optimize battery life (but not going to switch off pulse measurement as this should be part of a Smartwatch Mode). I have it paired with an iPhone Xr. Any views or similar experiences?

Many thanks,
Marc
  • 0 over 5 years ago
    Usually the advertised time is best case...

    I can make 2 weeks with my 935 but don't have it paired to my smartphone, another thing is to check the brightness setting and set it as low as possible (and workable for you). In my case I think I have it set to 5% or so and only when moving my wrist between sunset-sunrise or something.

    You might not use it much, but if it continuously has a connection and is transmitting msgs from your phone that'll impact battery (vibration settings are also interesting, all that stuff has an impact).
  • 0 over 5 years ago
    Is Pulse Ox monitoring on? That apparently seems to drain the battery quite a lot.

    I imagine if you turned everything off and left it on the clock screen for 2 weeks it might last that long. Not something would ever need as would be too keen to go and do a run or something.
  • 0 over 5 years ago
    Usually the advertised time is best case...
    In my case I think I have it set to 5% or so and only when moving my wrist between sunset-sunrise or something.


    Hate to tell you, but on 945 even on the latest software it is not possible to use that option to set backlight after sunset to save the battery. I hope it is a bug that will be corrected. So far I have not received any comments from Garmin regarding this.
  • 0 over 5 years ago
    are you using spotify or listening to music over bluetooth? That seems to have a big hit on battery. I charged mine up Fri (I think) and wear it 24x7. I've done 1 hour indoor cycling with it linked to pedals and external HR + 30min outside GPS, always linked to my phone and am on 48% battery. Walk >= 1hour a day but don't track GPS for those walks.
  • Former Member
    0 Former Member over 5 years ago
    Thank you for the responses so far. I switched off Pulse Ox and set the backlight to 5% as recommended - I keep it paired to the phone as that’s what Smartwatch mode is supposed to do. Thank you for sharing your experiences.
  • 0 over 5 years ago
    Is Pulse Ox monitoring on? That apparently seems to drain the battery quite a lot.

    I imagine if you turned everything off and left it on the clock screen for 2 weeks it might last that long. Not something would ever need as would be too keen to go and do a run or something.


    Meh, as mentioned... The forerunner 935 I have lasts about 2 weeks and that's with 3 activities a week (say about 3hrs total a week). The advertised stuff simply is an 'up to xxx days/hrs' and the more functionality you actually use the worse it gets. I don't really care about tons of notifications on my watch and all, so that helps..

    Still, even if you have everything on you'll still get decent battery life, just not the max.

    Hate to tell you, but on 945 even on the latest software it is not possible to use that option to set backlight after sunset to save the battery. I hope it is a bug that will be corrected. So far I have not received any comments from Garmin regarding this.


    I know, read about it... don't care too much to be honest. Guess it'll be added later on afterall... and if not, we'll manage.
  • 0 over 5 years ago
    Check out this one....

    Rode 3 hours roadbike yesterday. Took 17% battery w. power, cadence, speed. Startet from a full charge.

    Turned OFF PulseOX straight after training - read here in forum it does eat a lot of battery...

    Today - 23,5 hours later - with 24/7 OHR and smartwatch mode and wrist backligt 20% - battery is down to 77%

    That is 6% battery on almost 24 hours....! That should do for 16,5 day in standby!

    BTW - checked battey this morning too. From 2230 to 600 - 1% battery drop.

    #ILOVE945 ;)
  • 0 over 5 years ago
    I did an ultramarathon at the weekend that took 4:48 - that consumed 29% battery life on my Fenix 5+ which I think is not bad. Interesting to see the 945 figures.


    Based on your ride and my run, the 945 would last for 17:38 and the F5+ for 17:15! Not far off each other at all! I know there are loads of variables and our setting wouldn't be the same but so much for the amazing battery life of the 945! I was expecting 3 hours on the bike to take <10% battery on the 945
  • 0 over 5 years ago

    I have had a similar experience so far. I've had the watch for one week today and find that the battery is disappointing.  My 935 held a charge much better.  I feel that something isn't right.  i don't know if one of the smart functions is hung up.  I have optimized it in all the same ways I had my 935 set.  I seem to consistently loose 7-8% while sleeping. 1% per hour is unacceptable in my opinion. 

  • 0 over 5 years ago

    I have mine setup with only a few things changed from the default settings. Pulse Ox from 24/7 to sleeping only and backlight brightness set to 10%.

    I charged it to 100% Monday evening and have worn it 24/7, except when when showering, since with 2 50-53 minute outdoor runs and now on Friday morning it’s at 65.5% averaging 0.424% per hour.

    If you take the claimed battery life of 14 days in smart watch mode and do the math the draw per hour should be just under 0.3% so I’m okay with what I’m seeing.