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]

Another 5km measured parkrun this morning, which Fitbit recorded as 3.26km. getting worse!

Matt

[TAMAY]

Hi. I am having exactly the same issues... my hubby bought me a charge 3 for christmas to replace my broken charge 2. Every run i have done (about 6 now) has recorded inaccurately. I have done resets, noted wifi and gps recommendations etc, but still no joy. This morning a 10.3k run tracked as 8k, but annoyingly on the Map the splits showed 10.99k. Traced my route on Map My Run and it was 10.25km. Think im going to return the watch and research other brands

[MattBirks]

Yes, I know what you mean, the splits seem to record the right distance in that I seem to get medals for small parts of the run, but the overall distance is way out.

Sorry to hear you're having the same issue. Such a shame, as the charge 3 is just like the charge 2 but better. I'm sure the distance recording issue isn't the tracker itself, but that doesn't help.

Matt

[Vivianna]

My Charge 3 went from under recording in October to over recording in November onwards.  I have no idea how far the distance is but I always run the same route on a sunday morning and my fitbit has recorded the route from as low as 3.59k to as high as 6.8k.  My pace is therefore looking greatly improved!!  Im doing a half marathon in March and have bought bone conductors so I can listen to music and i was hopeful of using the fitbit voice cues for pace and distance.  Charge 3 is too unreliable to trust now.  

[TAMAY]

I exchanged mine yesterday for another one the same, in case it was a glitch with just this one. I'll try it for a couple of weeks and if this one is no better i will return it for a full refund and try a different brand - maybe a Garmin, but i need to do my research

[Vivianna]

I got my Charge3 as a freebie when we moved house and signed up with BT so I can't do much about mine.  I was  previously using a Charge 2 which I never had any problems  with.  I gave the Charge 2 to my son but I may do a swap with him  (he doesn't do any running to record 😁)

[MattBirks]

Been a while, but just to update. Borrowed a Garmin Forerunner to compare stats, and sure enough my Charge 3 with connected GPS is still way off.

I've tried manually setting the stride length to what the Garmin records, but still no better.

Had an online chat with a Fitbit support person today, and he was no use at all. In summary "GPS data comes from your phone, the tracker works fine as a fitness device". Ignoring the fact that the Charge 3 and phone worked totally fine until some random date in October and haven't worked since.

I'm going to try my Charge 3 tomorrow with my partner's phone, just to check that theory.

If the Garmin did more than just track runs, I'd probably switch.

Matt

[Rich_Laue]

But is either correct @MattBirks I can see many complaints on the Garmin forum about their accuracy. Some even are threatening to switch to Fitbit. 

We need to compare with a known standard, not an uncertified second device. 

Google pedometer would be better a choice for comparrison. 

Forget the cars odometer unless it has recently been checked against mile markers. 

[MattBirks]

Rich,

Thanks for the very valid points.

I was skipping some detail, I've also been recreating the routes on OS maps here in the UK and the distances are matching the Garmin distances, so I'm pretty comfortable that this Garmin tracker I've borrowed is good.

It's worth noting that I'm not looking for 100% accurate from the charge 3, but it's way short at the moment, which really screws my stats when I'm training. It adds around a minute per kilometre (and not in a consistent way) so I've no idea how well I'm running from one to the next.

I do agree, we need a good baseline to work from. I'm pretty confident the Garmin is close enough.

I'm going to try a run paired to my wife's iPhone today, see if that makes any difference.

[MattBirks]

So, installed the Fitbit app, paired my Charge 3 and ran with my wife's iPhone yesterday morning with the borrowed Garmin on my other wrist. What do you know, within metres of each other over about 4km (I was feeling lazy). 

So, it seems either my Samsung S10e GPS isn't working right, or the integration of that phone with the Charge 3 using Connected GPS isn't working right.

Time to start hunting the internet for any others with S10 series phones and Charge 3's having GPS issues....

I've rebooted my Samsung phone, cleared my whole cache partition, and turned off/on GPS. Will see if there's any improvement on my next run. 

Any advice out there?

[MattBirks]

Short run this morning, but after all the resets/cache clearing etc, my Charge 3 / Galaxy S10e combination actually over-recorded the distance this time compared to my "reference" Garmin Forerunner.

I'm going to set my stride length back to auto and do another run in a couple of days. At least I've achieved a change in outcome though. Always promising.

Matt 

[AdamH0]

I had this same problem for months before moving to garmin.

Regarding your observation on phone OS. My daughter and I had identical Charge 3s, but she has an iphone and I have a Pixel 2. We'd run side by side, and her distance, pace and route would be spot on. Mine would be all over the place. Zig-zags were common in my routes. (We could be running 6min/km pace on her fitbit, but mine would be reporting 5:20 min/km pace)

If the recording didn't have too many zig-zags it was correctable in Strava ('correct distance') later, but this doesn't help your pacing during the actual run.

The actual recording had all the right points, and times, but the cumulative distance figure (in the downloaded tcx file) is wrong by 10-20%.

[MattBirks]

Adam,

Yep, that's exactly the experience I'm getting. Thanks for the feedback.

I get the impression from your comments that you didn't find a fix then? Just bailed and got a Garmin?

Matt

[jamiecook89]

Hi Matt - I'm so glad I found this thread. I'm having the exact same issue with my Charge 2 and Samsung Galaxy S10+!

Did you ever get a resolution here? I've read all of your posts here, following intently in the hope you got to a solution! 

Any help you can offer would be greatly appreciated!!! 

[jamiecook89]

Hi Matt - I'm so glad I found this thread. I'm having the exact same issue with my Charge 2 and Samsung Galaxy S10+!

Did you ever get a resolution here? I've read all of your posts here, following intently in the hope you got to a solution! 

Any help you can offer would be greatly appreciated!!! 

[jamiecook89]

Double posted sorry 👍

[AdamH0]

Hi Matt,

Yes I've moved to Garmin forerunner 245 And am very happy with the running experience. It doesn't track sleep as well as the charge did though.

My daughter still uses her charge 3 and iPhone for running and gets good distance measurements. (This is why I took it to be an Android issue)

Adam

[MattBirks]

Adam,

I've had a similar experience. Works perfectly with my missus iPhone. And my Charge 3 worked fine with my old Galaxy S7. I've been tempted to talk to Samsung, but I can imagine how that conversation would go.

Jamie,

I've not been updating this thread, but I have been collecting lots of info. The summary is that if I leave the phone and FitBit to their own devices, the auto stride length wanders all over the place and I never get a good outcome. I've fixed the stride length to what I believe is correct and sometimes I get a good track, but not always.

I had some success clearing the phone cache in recovery mode and rebooting the phone before a run, but I need to experiment with that more, as I haven't tried it enough to prove anything. I was also going to test out just a reboot and just clearing the FitBit app cache. Just keep forgetting before runs.

Hope that helps? Please do try the same and report back.

Matt

[MattBirks]

I've been for two short runs today. I rebooted the phone before starting the first one and also cleared the cache for just the Fitbit app. Note, got I've still got a fixed stride length.

In both runs the Fitbit recorded 102% of the distance of the Garmin I've borrowed. Which is close enough for me.

Oddly I had to enable locations services for the Fitbit app when I opened it after the cache clear, so not sure if that setting was cached or something else is going on.

I'm going to just try clearing the Fitbit app cache before the next run and see how that works out.

Matt

[jamiecook89]

Hi Matt,

Thanks for getting back to me and for the update. I took your advice and tried a system cache clear, along with reboot of both devices. While that did seem to work and give me a much more accurate reading, by run number 2 or 3 the same problem recurred.

I'm going to try following those steps before every run to see if that's the best way around it. Complete pain and has really put me off of FitBit if I'm honest, especially if you're saying that other devices (e.g. Garmin) actually work OK with the Galaxy!