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Will the inevitable nightly height calibration drain my battery? How is it supposed to work?

KrapfenKringel
over 3 years ago

So with firmware 20 your watch is always going to do a nightly height calibration (+actives or only nightly).

Of course I want my activities calibrated, so I have to live with a nightly calibration. But what does it actually do?

GPS? No, I do an odd thing that is sleeping surrounded by 4 walls with a concrete roof on top, there is no GPS reception. So that's a waste of battery, that will hopefully time-out and not run for ever.

Calibrate based on maps of last known location? Also stupid, I'm not at my last known location, and even if I would, then there is the odd thing of me not sleeping on the streets but in a multi-storey building 40 meters above what the map would define as height.

Talk to my phone for some magic information (same rules of the watch would apply to my phone, it also does not know or can find out at what height its located)? But no, I don't keep my phone in the room I sleep in, and even if BT range would be good enough, I don't keep it connected 24/7.

So how is this supposed to work? At best I get a wrong height every night that luckily is corrected when I start an activity. At worst its draining my battery trying to get information it can't get.

  • 0 over 3 years ago

    Good question. Also interested to know where the watch will get the value for nightly auto calibration.

    Just one comment though : I think that it was not mentioned before but nightly autocalibration was already there before 20.00. It was just a default setting.

  • 0 over 3 years ago in reply to drkglb

    It was there, but you didn't have to use it. Now it can't be turned off. Only if you turn of calibration completely.

  • 0 over 3 years ago in reply to KrapfenKringel

    So, you can turn off auto-calibration completely in v20.00, and only use manual calibration?

  • 0 over 3 years ago in reply to n.y.a.n

    But why would I do such an annoying thing? Probably would completely forget when it matters..

  • 0 over 3 years ago

    I guess [disclaimer: all theory - I may be totally wrong] retrieving the altitude information is a request from the watch via phone or wifi to retrieve the altitude for location X from a service at Garmin. If no wifi and no phone, it can't be done, and should leave the altimeter alone. The altimeter will then drift depending on ambient air pressure.

    I don't know how location is determined. Can be via the phones location services, Wifi, maybe last known GPS location or -least likely- information in Connect on where you live.

    This auto-calibration should not cause noticeable battery drain, it is not a lot of data if it succeeds, and if it fails maybe a few retries will be done, but all that is based on common network/communications handling, and that is solid. (Not saying it's impossible to mess it up, but quite unlikely.)

    As I wrote in the 20.00 thread, if I ever find the time, I'll check out the phone logs and see what it does. Finding the time is unlikely, anyone else want to volunteer?

    My main gripes with this method: it results in incorrect calibration for anyone living in a high building, and - at least for me- it calibrates to a very wrong altitude (not at all ground level) which messes up the baro graph. But as I don't have the phone on at night, that is no problem.

    Anyway, long story short: the baro calibration is working again in 20.00; you can enter altitude and sea level pressure. That's what I do a couple of times per day. I have used ABC watches for so long, it's become a habit anyway.

  • 0 over 3 years ago in reply to KrapfenKringel

    No, I did not say that you should do that. I understand your wanted use case.  It was rather a question if it is still possible to completely turn off automatic calibration in v20.0? Like in v19.20. So you only rely on manual calibration. I do that in alpine settings, where calibration to DEM and GPS may be way off. In these situations manual calibration is better.

  • 0 over 3 years ago in reply to n.y.a.n

    Ah right, there is no "off" anymore, I still struggle with that.

  • 0 over 3 years ago in reply to n.y.a.n

    If you set it to AutoCalibrate Nightly, it will prompt for the correct altitude before each activity. If you then prevent the nightly calibration (by putting the watch in airplane mode or otherwise), in theory it should never calibrate other than manual. But there is no Off.

  • 0 over 3 years ago in reply to KrapfenKringel

    Ok. Thanks for the answer. I will stay on 19.20 for this reason, until further. Like you and others the new method would give wrong altitude for me each night, as I live a few floors up.

  • 0 over 3 years ago in reply to Bit

    Thanks. Understood. I use the barometer and altimeter daily, especially at high altitude to keep an eye on shifts in weather and during activities with high ascents/descents, where I manually calibrates to known altitudes at start and during the activity. I rather trust the built in sensor, than GPS and/or DEM data in steep environments.