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Battery Never Lasts 24hrs with 1sec Recording

Cronus4
over 6 years ago
The past weekend I did a 120K and my 935 barely made it to 16.5 hours, previous to that I had run a 100 miler and it only made it to around 17 or so hours. How is anyone (if anyone) getting 24hrs of battery from their 935?? I thought for sure it would make it through my 120K.

My settings during the run:
Auto Lap on (1mi)
Backlight: only on during auto lap notifications (shortest setting)
Navigation: 'Doing' a course (following 120K course)
Vibration: on for notifications
Sound: OFF
GPS: 1sec
Wrist Heart Rate: OFF
Chest Heart Rate: external Garmin strap
Bluetooth: OFF
Wifi: OFF

I like the light weight of the 935 and Garmin in general so I don't want to get a Fenix 5 whatever or Suunto 9 to be able to have a watch that lasts for my ultramarathons....

Thoughts appreciated.
  • 0 over 6 years ago
    Switch to Smart Recording. You will not gain a better accuracy with 1sec recording.
  • 0 over 6 years ago
    I suspect the course would have more impact on battery than the 1sec recording. Did you have any CIQ data fields? That could also have a potential issue. If it's really important to have longer life, you would want to experiment with both of these. I know at least on the older edge devices, having the map displayed would reduce the battery life by over 50%.
  • Former Member
    0 Former Member over 6 years ago
    I definitely managed much more than that on my 120 km trail ultra. Even though I charged during the run, I estimate that without charging the watch would have lasted 20, maybe even 22, hours with OHR on. Details of my settings are in my race report here: https://forums.garmin.com/forum/into-sports/running/forerunner-935-aa/1410809-setting-up-the-935-for-a-24hr-race/page2
  • 0 over 6 years ago
    never run that long, but surely it must have bluetooth or Ant+ on to communicate with the HR strap?

    I can't help thinking having auto backlight on would drain it as well, especially as it's going to come on every mile.
  • 0 over 6 years ago
    Hi,

    today I had bike ride. In total 195 minutes. GPS only + 2 ANT+ sensors (HR chest strap + Tempe). Battery usage: 14%, so it means 4,31% per hour. It means more than 23 hours for recording activity in this conditions. Pretty well..
  • 0 over 6 years ago
    The past weekend I did a 120K and my 935 barely made it to 16.5 hours, previous to that I had run a 100 miler and it only made it to around 17 or so hours. How is anyone (if anyone) getting 24hrs of battery from their 935?? I thought for sure it would make it through my 120K.

    My settings during the run:
    Auto Lap on (1mi)
    Backlight: only on during auto lap notifications (shortest setting)
    Navigation: 'Doing' a course (following 120K course)
    Vibration: on for notifications
    Sound: OFF
    GPS: 1sec
    Wrist Heart Rate: OFF
    Chest Heart Rate: external Garmin strap
    Bluetooth: OFF
    Wifi: OFF

    I like the light weight of the 935 and Garmin in general so I don't want to get a Fenix 5 whatever or Suunto 9 to be able to have a watch that lasts for my ultramarathons....

    Thoughts appreciated.



    I think that navigation and HR belt drains the battery very quickly.

    If you turn off the navigation and disable the HR monitor (i don't see the point in a ultramarathon) i think that you can manage to get more than 22 hours.

    Last year i've made a 2 days run. In the first day i have the BT conexion with my phone ON, Wirst HR ON, GPS+Glonass enable and 1 second recording. The battery last for 14:53 hours.
    Next day i turn OFF Wirst HR, BT conexion and Glonass and after 10:40 hours i still have 55% battery remaining.

  • 0 over 6 years ago
    I sometime use 'battery up down' CIQ data field. This gives two fields in the FIT file - current battery %, and current %/hour slope.
    You can see this on my marathon from a couple of weeks ago:
    https://connect.garmin.com/modern/activity/3105536620
    https://apps.garmin.com/en-US/apps/84104c99-6ad2-4bcb-8537-8bfb6d141089
  • 0 over 6 years ago
    disable the HR monitor (i don't see the point in a ultramarathon) i think that you can manage to get more than 22 hours.



    When running hilly ultramarathons I personally want the HR function because it helps me to pace myself early on in the race, there are plenty of people that blow themselves up at mile 30 of an ultra because they 'feel' good. You can feel good in an ultra at mile 30 and your heart rate can be in the anaerobic zone...
  • 0 over 6 years ago
    I sometime use 'battery up down' CIQ data field. This gives two fields in the FIT file - current battery %, and current %/hour slope.


    Although I can obviously recommend that datafield I must point out that using it is likely to increase your battery usage.

    Nice result at Chelmsford btw. Judging by your HR you pushed it fairly hard at the finish. I did the Chelmsford marathon myself for the first 4 years but didn't make it this year due to other commitments.

  • 0 over 6 years ago
    Yes - it will increase the usage a little - but I cant imagine it increasing by anything noticeable.
    I did the first Chelmsford mara as my first ever, but this is my first return since that one in 2014. The 3:30 pacer was sniffing at my heels with about 4 miles to go, so I had to bury myself to keep him at bay! Goal was 3:30, so really chuffed to get in well under that - altho my HR did hit new heights in that last few hundred !