Fenix 6 very inaccurate for indoor sports

I am not interested in the distance. This will be a total random number. But hr data and the movement recording in general is totally wrong. Hr changes do not get recognized (also with hr strap) - instead to the vivoactive hr+- and in 2 hours playing single the Fenix told me I just moved for 5 minutes. This is totally wrong for sure.  I did not buy the watch for that, but if a connect iq app can record this (hr and movement) the watch just seems to delete this and this does not have to be I think.

And before anybody says I bought the wrong watch, I really like it and did not plan to have a reliable way to record badminton.

Correct, unfortunate that they delete data, but this is the way it is.... For outdoor sports and strength workout I love the watch, best I had so far. Just great. So I just use my old vivoactive for badminton, it is also lighter and smaller, which is also OK if you have to use a racket 

So you have to use another device or use the connect iq app to record this activity 

 I had a vivoactive and there was a distance quite accurate - it was based on steps maybe, I dont know

You don't know how accurate that distance was. Chances are it was just a number based on a distance assigned to the number of steps counted. Since distance per step will be constantly changing there can be no guarantees you actually achieved a meaningful number no matter how much you liked the number.

EnormoDerClown said:

Hr changes do not get recognized (also with hr strap)

That's physiological as much as anything else. The heart does not respond instantly to changes in intensity. It lags when going up and lags when coming down. Although you are likely get a better response from a strap than the optical heart rate, neither will be truly accurate.

Again. I am not interested in the distance at all and the number could not interest me less. It is just that the Fenix obviously loses data. 2 hours training and just 5 minutes moving is totally wrong. That I  only moved  100-200 meters is also just a joke and that my heart rate never ever got over 100 whether I was totally exhausted is also just wrong.

I know the vivoactive will not track it 100% (and I do not try that) correct, but I have 1,5 hours movement, my heart rate has a range of 80-170 and and I have way more distance than (maximum!) 200 meters. I think we can all agree that this sounds far more realistic. 

That doesn't sound right.  I have run inside with my Fenix on a hotel treadmill and heart rate is measured perfectly (with Polar H10 heart rate strap) using the run application.  Maybe your strap was not connected and/or your optical HRM is faulty?  If there is some bug in the tennis application you could just use the run application since all you really care about is time and HR.

If you are using a strap to record the heart rate then you need to check the strap is working correctly. Have you done that? How good is the battery? Was the strap wetted before you started? Is the strap securely fastened? The movements associated with racquet sports impose different muscular movements around the chest that are likely to disrupt the heart rate sensors much more than cycling and running.

And if you are using the optical heart rate, then you've got what is to be expected - poor results. Which arm is the watch on? If it's the same arm as your racquet arm then try switching it to the other arm.

What activity are you using for badminton? What settings do you have? There have been many, many complaints over the years about Garmin watches recording steps when users feel they shouldn't - swimming, cycling, driving in a car for example. It is not beyond the realms of possibility that what you are experiencing is a side effect of some desensitising that Garmin have done. I might be entirely wrong of course and there might be a problem. Have you taken this up with Garmin Support? 

Was thinking about this as I was running just now. I'm sure I read somewhere that you have to do at least 10 recordable steps before Garmin will begin counting. Of course that might well be an anecdotal post that someone else posted without reference but if it is true that might explain why you get so few steps counted when playing badminton. 

I wrote a pedometer module for my Ambit2/3 watches years ago because there wasn't such function at that time.

The only reliable data I could use came from the cadence which uses the accelerometer. It was pretty accurate as soon as I was walking/running which gave me proper, consistent cadence and yes, it took 5-10 seconds until the watch fixed the cadence and provided the data and also when I stopped there were approx. 5 more seconds until the cadence got adjusted.

I suppose Garmin uses the same method in which case there is a couple of seconds needed to get steady cadence which can be used for the step counting.

However, it will only give proper results if the cadence is consistent. Throughout the day it does not matter much as sometime it counts a little less, sometimes a little more, but for activities like tennis or badminton I think it won't provide accurate or even closely accurate data.

It was the same with my old forerunner. I tried it multiple times with the second watch now. Tried at least 6 different sport modes. Used the hr from the watch and from different straps. All the same, just sports + from connect iq is recording the data. No "normal" mode.

I run every day at the moment because I am training for marathon and the watch is working absolutely great there (also for hiking or riding my bike). I tried on both arms (with changed settings in my profile). It will just not save all data what the watch is recording, there seems to be a smoothing or something like that. 

Accuracy is fine for outdoor tennis where I usually get around 2.5 km in an hour. Indoor tennis only give around 0.6 km in an hour, so that is really useless.