Battery drain during cycling and no HR if exercuse is started on the phone

[larsoleruben]

Hi
Fitbit Charge 6 with Iphone 15 Pro:

I just started using the Fitbit Charge 6. During my cycling workouts I noticed that the bateray drained pretty quickly. It took abot 2 hours for it to drain it completely.
I tried to read the instructions and found "it could use the phone gps". However the device was already set to "dynamic", meaning it should use the phone if available. I had the phone in my back pocket of the jersey.
I tried to set it to "phone" only, but then it just did not record any GPS.
Then I tried to start the workout from the fitbit app. It did record the GPC, but now with no HR?
So my question is: Should the device not use the phone GPS, when set to "phone" or "dynamic" and why is it not doing that?

[Rich_Laue]

Entering the execise on the phone is to be used when the user left their tracker home. You will also notice that fitbit does look at the trackers steps. 

[larsoleruben]

Thanks for the info.
But what I don't understand. is that when I set the gps tracking to "dynamic", the tracker should use the phone GPS and save battery on the tracker. Or you can even set it to "phone" only. But when I use "phone" only, it does not track GPS at all, and when I use "dynamic", it only tracks using the tracker built in GPS, which in turn naturally leads to battery drain.

[larsoleruben · Accepted solution]

I think I found the problem: The app had “use my position” at “only when I use the app”. It has to be set to always, to allow the tracker to get the gps from the phone, even when the app is not in focus

[Rich_Laue]

Yes @larsoleruben you are correct, when you open the app, you are only seeing the User Interface section. The rest of the the app starts with a phone restart, and handles, background sync, notifications, GPS,