Inaccurate Distance Reading on Charge 2 Run

[benw31]

Hi everyone,

Completely new to FitBits so bear with me as I am no doubt asking a very obvious question...

I'm not new to running but new to wearable tech to measure my stats - I've always used mapmyrun and such to see my distances, etc. So I've done a couple of runs so far using the FitBit and was surprised at how poor my minute/km pace was at the end of it. The distance didn't seem right for the time I clocked.

Last night I did just under a 10km run according to my FitBit. Got the right hump at my time and so checked the distance according to mapmyrun and mapometer which both came out as 12.5km!

I think I might know why it isn't recording accurately but wanted to check beforehand... So I haven't been running with the FitBit connected to my iPhone 6 (I leave my phone at home - I know, not safe, but I hate running with it on me). So am I right in thinking that because it isn't linked to any form of GPS whilst I'm running it calculates the distance based on my 'stride length'? That would make sense to me and not surprising that it is off - I have different stride lengths depending on hill trajectory, etc.

So if I was to start carrying my iPhone with me during runs and have the FitBit linked to it would the distance come out accurately? And do I have to do anything special to pair the two or does it just automatically connect them when I start the run?

Thanks in advance - really appreciated! Apologies if these are stupid questions.

Ben

[Julia_G · Accepted solution]

Hi, @benw31, you are correct in thinking that if you run with your Charge 2 without your phone it will use your stride length to calculate distance, and this will obviously always be an estimate.  

Using "connected GPS" will give you a more accurate calculation of distance.  Here is an information post about connected GPS.

Basically you must start the activity on your Charge 2 and make sure it connects successfully to your phone.  Press the button until you come to the first of your "exercise shortcuts" then tap until you see "run". Press and hold the button to start.  You will see a phone icon on the screen indicating it is trying to connect.  When it is connected you will be ready to go.

I hope this helps.  Please post again with any further questions.  There is always someone here to help.  Welcome to the forums!

[benw31]

Thanks @Julia_G! Really helpful and informative.

I'll be sure to take the phone out with me and connect it to the GPS on my next run. Fingers crossed it will be accurate 🙂

[Julia_G]

Hi, @benw31, I'm really glad if this helps.  Let us know how it goes.

[benw31]

Hi @Julia_G, thanks for your help so far but I need further guidance I'm afraid.

I went for another run today and went to connect the fitbit to the gps (as per the instructions) but it came up with the message "check your fitbit app." I had the fitbit app open next to the watch, nothing came up on the app and when I dismissed the message on the watch it just had the phone symbol at the top with a line through it.

I tried it several times with no luck. The fitbit is definitely connected to my phone via the bluetooth and it shows up as being connected in the app. I tried switching the bluetooth off (which then came up with the message that my fitbit had been disconnected on my phone - so again, I know it is connected, I also checked in my Bluetooth settings and it has 'Charge 2' as connected) and reconnecting the fitbit and starting the Run process again but no luck.

So after half an hour of trying and getting very frustrated I decided to run without it connected and just let the fitbit record the data without it whilst running the Strava app on my phone. Have checked the distances by the way (map my run, Strava, etc) and the fitbit again said 10km but was this time 3km less than the actual distance.

Any guidance or help with why it won't connect would be great!!

Thanks, Ben

[benw31]

I've seen the below suggestion elsewhere for something similar but have tried it and it also does not solve the issue. It is showing as being connected to the app/iPhone just won't link with it for a run and comes up with the "Check Fitbit app. Press button to dismiss" prompt followed by the phone symbol crossed out.

Suggestion tried and not worked:

"Try restarting your phone's bluetooth and GPS then restart your tracker by doing the following:

Plug the charging cable to your computer or UL certified wall adapter. 
Align the contacts of the tracker with the charging cable and plug it in making sure it snaps securely.
Your tracker should start charging.
Press the button for 10 to 12 seconds.
You should see your tracker's firmware version and you can now unplug your tracker.

Now go to the bluetooth settings area and remove any devices listed there including your Fitbit Charge 2 then go to the app and retry syncing them to refresh the link between them. After this retry logging your run with GPS making sure your phone has good GPS and internet signal and turn off the wifi so it only uses mobile data."

[Julia_G]

Hi, @benw31, I am not sure that I can help with that one.  I have had similar issues with "connected GPS" -- I always assumed that it was my phone.  Some people find it works very well for them, but I usually had to re-start my exercise repeatedly before getting a good connection to the phone, and even then sometimes it would lose connection again after only a very few minutes.  I think that my phone's Bluetooth was not strong enough.  I am afraid that it was so hit or miss for me that I now don't use connected GPS for running any more (I now have the new Ionic, which has a built in GPS chip).  Sometimes connected GPS worked well, but it was frustratingly inconsistent for me.

The only tip that I can share is that you cannot make the initial connection unless your phone is connected to the internet (either by wifi or mobile data).  If you weren't connected to the internet at all, that would explain your difficulty.  If you were connected using your phone's mobile data, you might try starting a connected GPS run while your phone is connected to the internet via wifi (if you are starting from home or somewhere with wifi) to see if that helps.  Once your Charge 2 and phone has successfully started a connected GPS activity, you do not need data or wifi to maintain the connection, but you do need a robust Bluetooth connection the whole time.

Sorry not to be more help...

[benw31]

Thanks for your help @Julia_G. I have tried your suggestions to no avail. I have decided to make a new topic on this as I think people may overlook this topic as it is 'solved' - which technically is true as you did solve the original question, it's just that the solution isn't working on my Fitbit.

Hopefully I will be able to get the GPS to work otherwise I will have to ditch the product and find an alternative.

[FlanInTheFace]

What is margin of error when non-gps distance is measured based on average stride length? Does the estimated distance tend to be over or underestimated? Etc?