Charge 3 under-recording distance on GPS

[MattBirks]

Hello all,

I have read other users posting similar issues, but not seen any actual solution. For a bit of background, I've had my Charge 3 since Xmas having had a Charge 2 for a couple of years before that.

I wear the Charge 3 all the time and use it for step/sleep tracking etc, but primarily I track my (short) runs linked to the GPS on my android phone. The Charge 3 has worked perfectly well for all of these things until some time between Oct 3rd and Oct 5th, as I can see the 2 runs in Strava where the issue started happening.

Since Oct 5th the smooth line of my tracked run has regular short zig zags in it, like it's been folded back on itself, and the Charge 3 under-reports the distance run by some margin. For a 5km run it tends to now report about 3.7km. This is using the GPS from my phone, which I always ensure is connected before I start running.

I've checked the stride length and that's the same as it always was - although it makes no difference when using GPS anyway.

I've done multiple runs in different locations at different times and the same behaviour occurs. I've also recently upgraded my android phone. I have new phone hardware, new android version, and it's exactly the same,so is clearly not the phone.

I put up with it for a while assuming it was some glitch with the processing of the data at the FitBit end, but it's becoming really frustrating now - the primary purpose of my tracker (for me) isn't functioning.

Anyone have any helpful advice?

Matt

[MattBirks]

Been stuck in working for days now. Going to try and squeeze a run in tomorrow. Just going to clear the Fitbit app cache and see if that's as good without the reboot.

If so, I can live with that for now. Although I'll be having a chat with Fitbit support again if I can make the combination work by manipulating the Fitbit app.

[Vivianna]

How/where do you clear the cache?

Thank you

[Vivianna]

How/where do you clear the cache?

Thank you

[MattBirks]

On a Samsung Android phone, Settings, Apps, Select Fitbit app, Storage, Clear cache is at the bottom of the screen. Don't hit Clear data, that would not be useful.

Matt

[jamiecook89]

Having conducted a few more tests guys, I'm firmly now of the opinion that
the Fitbit calculates run distance by stride length and time, rather than
using the phone's GPS as it states.

This doesn't happen all of the time and it doesn't make it clear how or why
to alter this.

Ultimately, for a budget fitness tracker (that's now a few years old) it's
not going to be a perfect tracker. The new Charge 4 has integrated GPS and
tbh I was looking to treat myself to a new tracker anyway, so I think I'm
going to get and test out that.

Thanks everyone for your help!

[Vivianna]

Thank you so much Matt!

[MattBirks]

Jamie,

I don't agree, as my Charge 3 worked fine on connected GPS with my old Samsung phone and works fine now with my wife's iPhone. There's an issue with Charge 3 and Samsung S10e, at least in our cases. Not that I'm trying to stop you buying a Charge 4. I'd probably be tempted if I could afford it.

Just to update. I tried just clearing the Fitbit app cache before a run and didn't get good results. I also tried rebooting the phone and then clearing the Fitbit app cache just before starting a run, this seems to give a better results (102%, 102%, 106% compared to Garmin). Which makes me think it's not the Fitbit app cache, possibly it's some GPS cache. I might test just the phone reboot, see if that produces similar outcome.

I need to repeat the tests some more to get a significant number of results.

If I can show that it's not the Fitbit app, then I can start talking to Samsung.

Matt