Today I started an indoor session with only 15% battery. At about 45 minutes in, I got a low battery warning which prompted if I wanted to switch to battery save mode. I selected yes and the screen dimmed, then almost immediately I got a count down saying sleeping in 3,2,1 and it went to sleep. A few minutes later it woke up, then almost immediately repeated the sleeping in 3,2,1 shutdown process. This happened several times. It seems that by the time the low battery alert occurred the battery was already way too low to keep the device running even in low power mode
FWIW I have general suspicions about the accuracy of the battery percentage display. I have finished a ride with it on 61% and started riding again the next day with it miraculously appearing as 73%. I then rode 30 miles over and it still said 73% to the point that I assumed it was stuck - before eventually starting to drop again 'normally'. I have also seen it drop from 100% to 93% within a mile of leaving the house - and then barely moving for hours. Based on this I have avoided letting it get below 20% as I feared exactly the scenario you have described happening (on the 800 I knew I could get at least another hour out of it after the first warning).
In fairness the battery life itself does seem excellent (although that seems to have been partially achieved by scaling back the colour contrast to such an extent that night time navigation is a frustrating experience if you prefer not to use turn by turn) - I'm just not totally convinced the displayed percentage is particularly reliable.
Today I started an indoor session with only 15% battery. At about 45 minutes in, I got a low battery warning which prompted if I wanted to switch to battery save mode. I selected yes and the screen dimmed, then almost immediately I got a count down saying sleeping in 3,2,1 and it went to sleep. A few minutes later it woke up, then almost immediately repeated the sleeping in 3,2,1 shutdown process. This happened several times. It seems that by the time the low battery alert occurred the battery was already way too low to keep the device running even in low power mode
Could be wrong because I haven't activated low power mode yet but I thought that was exactly what was supposed to happen, the screen turns off and turns back on when a sensor or you activate something.
I think he means the device literally went to sleep, meaning it was no longer recording/usable - at a point where it sounds like it should have theoretically still had 9% battery left. In battery save mode the display should dim (and remain dimmed until it's triggered by something like a turn notification or human intervention) but the device should still be usable until the battery actually dies - at which point it goes to sleep (as seems to have happened here)..
I have run mine down into battery save mode and it still worked normally - just with a totally unlit screen by default unless reactivated by me or a turn.
Good to know I will have to put mine in the power save mode tonight and see what happens, just off what I've read, I was always under the impression that the device would act like it was asleep until you or a sensor woke it up, even the manual says it turns off.
Turning On Battery Save Mode
Battery save mode adjusts the settings automatically to extend the battery life for longer rides. During an activity, the screen turns off. You can enable automatic alerts and tap the screen to wake it up. Battery save mode records GPS track points and sensor data less frequently. Speed, distance, and track data accuracy are reduced. NOTE: History is recorded in battery save mode when the timer is running.
Select > Battery Save Mode > Enable.
Select the alerts that wake up the screen during an activity.
Actually, ignore me, you are correct - there is indeed a sleep countdown after which it should still be recording. In which case you may also be correct that Dave misinterpreted this as the entire device going to sleep when actually it was still running in the background.
I think I have also seen where users have asked after waking the device up if there could be a setting to adjust how long it stays awake sounds like it’s pretty short. Even on my long rides I am pretty impressed with battery life so I haven’t needed to try the low power mode ????
Yes, it's pretty quick - and immediate after you first enable it (I actually remember now, it slightly terrified me also until I realised it was actually still 'on' after this - maybe the 820 is slightly different, as I can't really remember noticing it before that).
I think part of the confusion stems from the slightly ambiguous use of the word 'sleep' (which isn't mentioned in the instructions for this section) which would usually imply that the device isn't being used at all but will wake up quickly - when what the user is probably expecting is for the device to remain 'awake' but with the screen blank (or at least dimmed) unless tapped..
Actually, ignore me, you are correct - there is indeed a sleep countdown after which it should still be recording. In which case you may also be correct that Dave misinterpreted this as the entire device going to sleep when actually it was still running in the background.
It's possible, the weird thing was it kept going into sleep mode then coming out maybe a minute later, then going back in etc. I'll try and find the ride file and see if was still recording
You're right, it was still recording with the screen blank. Funny thing is it was still recording yesterday when I finally got around to putting it on charge. It then automatically uploaded to Strava :)
My device now wont exit power save mode even after charging to 100%. It still continues to blank the screen. I ended up turning power save mode off as that seemed to be the only way to reset it.
