I wonder if you have any plans to include rider weight as well or maybe that's getting too complex?
You can do it if you register and log in. Then, click on the tab "Profile" and click on the "edit" button. Here you can edit the biker weight and rider power levels.
The only flaw, which is forgivable is the battery usage.
If the prediction is not accurate enough and you have a wattmeter, you have many options to improve the model.
-Click on the tab "bikes" and edit a bike profile. Check that all parameters are ok (you can check graph on the right to see predicted behavior depending on slope and rider power level.
-If you can register consumption at 5, 10, 15, 20... kph on a flat road, then you can use this information to fit the real friction model tacking into account motor model. See the blue button "optimize friction model" in bike properties. (I have to do a tutorial video on this).
-Once you have both a good drive system and friction force model, you can register few trips with know travel time and energy consumption to get an unbiased model (empirically taking into account external environment).
You can check the corresponding tutorial video.
I believe that with these parameters, you should get the best prediction. Then, you always have to deal with the fact that depending on the rider power level input, battery consumption can vary a lot in some cases. Most of the time, I am looking for an interval using 2 riding powers more than one predicted value having less meaning.