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abrensch / brouter

configurable OSM offline router with elevation awareness, Java + Android
MIT License
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Energy computation for hiking mode #135

Open Phyks opened 5 years ago

Phyks commented 5 years ago

Hi,

Following https://github.com/abrensch/brouter/commit/46c114ba1efda101d421171e27c918aaaec19758, I guess we should look at a usable energy model for hiking. So far, I found https://www.brianmac.co.uk/energyexp.htm and http://sprott.physics.wisc.edu/technote/walkrun.htm which might be of interest.

This issue is just to keep track of the ideas and possible implementations.

Best,

abrensch commented 5 years ago

Just a few thoughts on that:

the energy display in BRouter-Web was done originally for cars, with electric cars in mind. The value is displayed in kWh and the meaning of the value is "mechanical energy measured at the wheel".

So if you buy a 40 kWh Renault ZOE, there's 10% "reserved" capacity and 10% in engine and batterie - so if BRouter-Web shows 32 kWh for a trip, it will fully empty the battery.

Don't know if that's a good concept - but it's exaclty the same for bikes now. At least in Germany there's a very popular category of electric bikes: engine limited to 25kmh, power limited to 250 W and usually 1/3 of total power expected from the biker itself. Battery capacities of Pedelecs are advertised in "Wh".

So here we have the situation that if BRouter-Web shows "0,40 kWh", that means pretty much that you can do that with a 400 Wh Pedelec in a medium power setting (out of low/medium/high). 400 Wh is not really what the engine brings to the wheel, but the losses here a compensated by the biker bringing it's share.

So that's a value with a real-life meaning for part of the bikers. The other part would expect the display to be in "calories" and to be equivilant to what's displayed on the ergometer in the gym. Howver, ergometers do not display mechanical energy, but multiply that by some physiiolocial factor.

So if thinking of an energy diaply for hikers I think it should also be in calories and be calibrated to what's displayd by ergometers.

Phyks commented 5 years ago

the energy display in BRouter-Web was done originally for cars, with electric cars in mind. The value is displayed in kWh and the meaning of the value is "mechanical energy measured at the wheel".

Thanks a lot for the details on the backlog and history for energy in BRouter!

Don't know if that's a good concept - but it's exaclty the same for bikes now. At least in Germany there's a very popular category of electric bikes: engine limited to 25kmh, power limited to 250 W and usually 1/3 of total power expected from the biker itself. Battery capacities of Pedelecs are advertised in "Wh".

Same opinion here, I think this could really be a useful metrics for electric bikes (but I don't have any electric bikes nor meter to check the accuracy of BRouter computation :/). This could also be used for people doing kind of sportive biking and in need of having an estimate of burnt calories.

So if thinking of an energy diaply for hikers I think it should also be in calories and be calibrated to what's displayd by ergometers.

Same here again, and that is what drove my research for formulas and ways to compute this :)

vigiraud commented 3 years ago

Hi ! I also think it would be better having energy estimation in kilo-calories. It's more suitable for someone riding a mechanical (non-electric) bike. Even if its about the net power output.

Also, in brouter-web, it would help not having to compare small fractions of KWh. Maybe the best solution is adding an unit option in brouter-web ?

poutnikl commented 3 years ago

@2lafru Note that BRouter-app and Brouter-web share the common Google group, but they have independent authors and projects on GitHub. The latter is in nrenner/BRouter-web, in case of posting a feature request.