Configuring a Garmin Edge 800 for an emtb

[Injidup]

My Edge 800 bike computer calculates calories burned on a ride. I assume it uses the values I’ve entered (my weight, bike weight) plus altitude and speed. Does anyone know if it’s possible to allow for an emtb in these calculations?
I know the new Edge has/will have a connection to the Steps module, but I don’t want to buy a new computer when the 800 works well.

 

[Gary]

The calorie consumption data isn't actually very accurate from a garmin Edge 800 when it records a regular mtb activity. There's absolutely no chance it'll be accurate for Emtb rides. But I wouldn't rush out and buy a new Garmin if calorific data is your only reason. Even the latest most expensive cycling GPS garmin sell won't give a very accurate calorific burn value when riding an Ebike. All of their GPS units calculate calorie usage based on algorithms and with mtb riding there are simply far too many variables for the algorithm it to be accurate ad a variable assistance motor assist and there's absolutely no chance of accuracy..
If you have the HR strap for your garmin 800 and start recording in the same way you would to record an indoor trainer sassion it'll be calculating calories from HR zones and duration alone. it still won't be hugely accurate but it'll be a lot closer than recording the GPS route will. You'll need to turn GPS off to do this so you'll basically just be using the garmin as a HR monitor.

If you want anything close to accurate calorie count results from a garmin that's tracking your route while riding an Emtb, enter your weight and the bike's weight accurately in your profile, fit slicks to it, leave the motor off the entire ride and do not venture off road. Basically turning your Emtb into a very heavy roadbike. But even road riding calorie values aren't super accurate with these things. This explains the main methods of obtaining calorie data and why some methods are less accurate than others.

How calorie measurement works on Garmin fitness devices

Also. not a test of Garmin's algorithms but you should get my point

Fitness trackers accurately measure heart rate but not calories burned

 

[Injidup]

Thanks, Gary.
I had a look on the Garmin forums and as you say, it seems the 800 is pretty poor at calorie calculation. I won’t worry too much about it then! It is as DCRainmaker says, only for cookie allocation metrics. Or biscuits in proper English!

 

[Gary]

On a non Ebike I actually think Strava's algorithms do a better job of guestimating the calorie data from a Garmin.Than Garmins software.
Having used myfitnesspal in the past for calorie counting and linked it to strava and comparing results using a phone ,tomtom and garmin to record ride data the individual calorie results hilariously differ. MFPs guestimates are wildly out, Strava with a phone (no HRM) wasn't bad on the road but could be wildly out off road whereas Strava's with HRM data (even imported from the garmin) are actually not too bad. somewhat believable anyway... I tended to go with the lowest reading as afterall it is as you say mainly for biscuit (takeaway and beer in my case) allowance.
it's still worth using a HRM strap for all your rides when calorie counting. Just try not to be fooled into being a slave to it's inaccuracy in calorie counting. You should know fine well a 2hr Emtb ride of say 20miles and 3000ft elevation isn't burning anywhere near the 2000+ Kcal the software is telling you.
For example. A proper hard effort ride on the road from a Cat 1 road rider won't burn as much as 1000kcal in an hour.

 

[TPP]

use google to convert Kcals in KJs. Then work out how many KJs of battery energy has been used by the motor. ie 500Wh = 500W power for 1 hr = 500J per second for 1 hr = 500J x 60 x 60 = 1,8000,000J = 1800KJ
then multiply by % of battery used.
Convert back to Kcals. In example above 1800KJ = 430Kcals
Subtract from total given by Garmin/Strava

Obviously change figures for bigger or smaller battery

 

[Gary]

Where can we buy one of these 100% efficient Shimano battery motors that show accurate battery consumption percentages?

For anyone seriously training and wanting the most effective data collecion equipment to train by . let's face it an Ebike just isn't the correct training tool. (not a bad tool for general fitness though and way more fun anyway)

Just use common sense. If you're puting on weight cut down on the pies and ride more. if you're running out of energy during long rides eat better carbs more often.