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I've just shopped for a running watch, and while the AMOLED screen watches look nice, they claim to have ~50% the battery life in GPS mode compared to transflec

I've just shopped for a running watch, and while the AMOLED screen watches look nice, they claim to have ~50% the battery life in GPS mode compared to transflective LCD display watches. The article suggests a near-term 25% efficiency gain from this tech, so seems unlikely to translate to >2 day battery life.

jeffbee 3y ago
I have a Garmin with an OLED display and I usually have to charge it once a week or so. The GPS is by far the biggest power consumer. During activity tracking with the GPS turned on the battery lasts maybe 10 hours. It doesn't feel like a change in display technology would meaningfully change that situation.
- xur17 3y ago
  Do you use it with the display always on, or do you have it wake up whenever you look at the display? I have a Garmin watch with a transreflective display, and end up charging it ~once a week with 1-2 hours of activity tracking per day.
- FredPret 3y ago
  Why do these Garmins outlast Apple Watches by 5-10x? Is it because they're bigger? Or does the Apple Watch do more things?
- londons_explore 3y ago
  > GPS is by far the biggest power consumer. There are some cool research papers about delayed processing of GPS data in the cloud. The idea is you turn the GPS on for just a few milliseconds, record the raw radio data (without getting a GPS location fix), and do that every 10 seconds or so. Then later you upload all the collected data to a big cloud compute cluster which can figure out all the locations (and where battery life doesn't matter). People are using that technique to have GPS trackers with years of battery life - handy for things like tracking animals.
  - xur17 3y ago
    Do you have any idea what the storage requirements are for a solution like this?
    - londons_explore 3y ago
      Pretty high - each location sample is hundreds of kilobytes if I remember correctly, although it was possible to trim that down if you knew there was a strong signal or you were happy to have some probability of an incorrect location. Annoyingly I can't seem to find the paper now.
  - ska 3y ago
    Tracking animals would seem to be a different set of requirements than, say, turn-by-turn car navigation. I'd imagine that for a lot of research, longer lifetime would win over real-time ish data, and possible you don't care so much about precision and granularity either. You probably want to upload semi often or risk losing the whole thing, but otherwise minimize batter use.
    - jeffbee 3y ago
      GPS already isn't good enough for car navigation, which also integrates wheel rotation and steering angle sensors. Even on a bicycle the tracking is noticeably better when you add a wheel rotation sensor to a GPS head unit.
      - ska 3y ago
        Interesting! That doesn't really change the argument, does it? "Where am I right now", is a different requirement than "where have I been, roughly, over the last 6 mo"
        jeffbee 3y ago
        Yeah I was trying to agree.

jeffbee 3y ago

I have a Garmin with an OLED display and I usually have to charge it once a week or so. The GPS is by far the biggest power consumer. During activity tracking with the GPS turned on the battery lasts maybe 10 hours. It doesn't feel like a change in display technology would meaningfully change that situation.

xur17 3y ago
Do you use it with the display always on, or do you have it wake up whenever you look at the display? I have a Garmin watch with a transreflective display, and end up charging it ~once a week with 1-2 hours of activity tracking per day.
FredPret 3y ago
Why do these Garmins outlast Apple Watches by 5-10x? Is it because they're bigger? Or does the Apple Watch do more things?
londons_explore 3y ago
> GPS is by far the biggest power consumer. There are some cool research papers about delayed processing of GPS data in the cloud. The idea is you turn the GPS on for just a few milliseconds, record the raw radio data (without getting a GPS location fix), and do that every 10 seconds or so. Then later you upload all the collected data to a big cloud compute cluster which can figure out all the locations (and where battery life doesn't matter). People are using that technique to have GPS trackers with years of battery life - handy for things like tracking animals.
- xur17 3y ago
  Do you have any idea what the storage requirements are for a solution like this?
  - londons_explore 3y ago
    Pretty high - each location sample is hundreds of kilobytes if I remember correctly, although it was possible to trim that down if you knew there was a strong signal or you were happy to have some probability of an incorrect location. Annoyingly I can't seem to find the paper now.
- ska 3y ago
  Tracking animals would seem to be a different set of requirements than, say, turn-by-turn car navigation. I'd imagine that for a lot of research, longer lifetime would win over real-time ish data, and possible you don't care so much about precision and granularity either. You probably want to upload semi often or risk losing the whole thing, but otherwise minimize batter use.
  - jeffbee 3y ago
    GPS already isn't good enough for car navigation, which also integrates wheel rotation and steering angle sensors. Even on a bicycle the tracking is noticeably better when you add a wheel rotation sensor to a GPS head unit.
    - ska 3y ago
      Interesting! That doesn't really change the argument, does it? "Where am I right now", is a different requirement than "where have I been, roughly, over the last 6 mo"
      - jeffbee 3y ago
        Yeah I was trying to agree.