Wattage per mile or kilometre

[Mass Deduction]

The numbers Ravi posted are inline with my experience and many other peoples posts, I have done rides as low as 4wh/m and as high as 25wh/m. I like it best around 10-15wh/m. You are trying to equate this to actual user effort which just isnt the case. My highest ever 25wh/m on a juiced CCX was an average speed of 21mph with a good 15-20mph headwind/tailwind going up and down 4-6 degree grades for 20 miles (an out and back ride so the tailwind turned into a headwind halfway into the ride). One of the hardest ebike rides I have ever done as verified by my heartrate monitor.

I had a loaner shimano e8000 bulls eMTB(500wh battery) for 2 weeks and rode it a ton. On max assist I could easily run out of juice in less than 20 miles (flatish ride with head/tail wind) maxed out at 20mph for the whole ride. My Bulls Brose ebike (650wh battery) usually comes back with 2/3 bars left out of 5 for the same ride/conditions/assist. I have done this ride twice on the bulls on the same charge although a tad slower on the second ride.
[...]

STePS 8000 is an older motor. STePS 6100 and 5000 are newer motors that are more efficient. That's why I highlighted them in my post.

 

[PaD]

Really interesting thread. I am in the market for an ebike. I am wondering how much W/km is consumed at speeds around 45km/h (28mph)?

I am looking at my options and battery needs for a commute of 32-34km where I could in theory goes to 45km/h for 12-15km and remaining parts would be around 30km/h.

Thanks for any infos!
Cheers!

Perhaps the Bosch eBike Range Calculator can serve as an indication on what to expect. It’s easy to change all important variables to see how it affects you expected range.
You need to choose the Performance Line Speed motor to set average speeds above 20 mph.

eBike range calculator for Bosch drive systems - Bosch eBike - Bosch eBike Systems

Use the eBike range calculator for Bosch drive systems to plan out your next ride.

www.bosch-ebike.com

 

[Stefan Mikes]

Perhaps the Bosch eBike Range Calculator can serve as an indication on what to expect.

Very interesting concept. Assuming 100 kg rider on "athletic/tour bike" with hybrid bike tyres who can pedal at 80 rpm, flat, windless, summer condition, good asphalt:
Riding at 45 km/h requires substantial effort and the range would be 37 km, that is, 625 Wh / 37 km = 16.9 Wh/km.

I am looking at my options and battery needs for a commute of 32-34km where I could in theory goes to 45km/h for 12-15km and remaining parts would be around 30km/h.

OK, now let us calculate what Balinus might expect. At 30 km/h, the same conditions, the estimated range 70 km with 625 Wh battery makes the consumption factor equal to 8.9 Wh/km. 15 km * 16.9 Wh/km = 253.5 Wh; (34-15) * 8.9 = 169.1 Wh. 253.5 + 169.1 = 422.6 Wh under ideal conditions and I assume using Turbo mode for the whole trip.

Meaning if that would be at least a ride in flat terrain, a speed e-bike with a 625 Wh battery might do. Factors like wind, temperature, rough terrain might still be covered by extra battery capacity. However, if the terrain is hilly, I am certain either double battery or a spare battery might be necessary.

 

[Balinus]

Very interesting concept. Assuming 100 kg rider on "athletic/tour bike" with hybrid bike tyres who can pedal at 80 rpm, flat, windless, summer condition, good asphalt:
Riding at 45 km/h requires substantial effort and the range would be 37 km, that is, 625 Wh / 37 km = 16.9 Wh/km.





OK, now let us calculate what Balinus might expect. At 30 km/h, the same conditions, the estimated range 70 km with 625 Wh battery makes the consumption factor equal to 8.9 Wh/km. 15 km * 16.9 Wh/km = 253.5 Wh; (34-15) * 8.9 = 169.1 Wh. 253.5 + 169.1 = 422.6 Wh under ideal conditions and I assume using Turbo mode for the whole trip.

Meaning if that would be at least a ride in flat terrain, a speed e-bike with a 625 Wh battery might do. Factors like wind, temperature, rough terrain might still be covered by extra battery capacity. However, if the terrain is hilly, I am certain either double battery or a spare battery might be necessary.

Thanks! I get similar results using the numbers provided. It is flat terrain, but some winds are to be expected (paths along the St Lawrence River) most of the time. I was looking at the Giant Fastroad E+ EX PRO with a battery of 375Wh + the 250Wh Range extender (625Wh total). I guess I'll have enough for a high assist commute! For windy days, I could lower the assist and do more effort myself

Thanks again. Really interesting thread about battery and consumption!

 

[Stefan Mikes]

A question off topic, @Balinus. Are there many dedicated bike lanes in Montreal? If so, you are living in a perfect country!

 

[Balinus]

A question off topic, @Balinus. Are there many dedicated bike lanes in Montreal? If so, you are living in a perfect country!

Yes there is! There is close to 1000km of bike lanes in Montreal and there is a plan to double it to 1800km.

(sorry, french link)
https://www.lapresse.ca/actualites/...montreal-veut-doubler-son-reseau-cyclable.php

We now have some bike lanes where the snow is removed in winter.

According to this report, its one of the good city where to do cycling.

Montreal Ranked #1 Best Cycling City In North America

We ranked 18th worldwide!!

www.mtlblog.com

With that being said, I do not do cycling between november 1st and april 10-15th. Too cold and I consider the conditions dangerous.

[end of promotional material]

 

[Stefan Mikes]

We had only 500 km of such lanes in Warsaw in 2017 but this number grows fast. Surprisingly, bike lanes are quickly built in very small towns and villages. In my neighbourhood, there are plenty of them, all new and even under reconstruction from older "cobblestone" type (I don't know a proper English term for that) to tarmac.

Whenever I ride my regular pedelec (not the speed e-bike), I take the full benefit. Still jealous about the Canadian infrastructure!

 

[Balinus]

We had only 500 km of such lanes in Warsaw in 2017 but this number grows fast. Surprisingly, bike lanes are quickly built in very small towns and villages. In my neighbourhood, there are plenty of them, all new and even under reconstruction from older "cobblestone" type (I don't know a proper English term for that) to tarmac.

Whenever I ride my regular pedelec (not the speed e-bike), I take the full benefit. Still jealous about the Canadian infrastructure!

The infrastructure is not perfect though. As soon as you leave Montréal, the available bike lanes are not numerous or well developed (in my opinion). This is even worse in small town or villages: the density of population is very low and the distance are important, hence this is perhaps superfluous to have bike lanes in most villages. I must also point out that most car driver dislike bikes in general sadly!

So Warsaw? I guess you know a lot about winter too!

 

[Manu]

It needs time to kill a man with electricity. The higher voltage the higher amperage, meaning watts (energy rate = energy transfer speed). These watts need to accumulate in the body as watt-seconds, or Joules.

Sorry you missed physics lessons at school.

As I said at the time, the battery is measured Voltage per amp Vx Ah, that battery has a capacity in watts/hora , no matter how long you use be watts or watts hour, it stores and you can burn it in second zero, within one hour or 2 days depending on the charge of electricity consumption that you put. Engineer, you are talking to an electrician and industrial refrigerator .

It's like when I told you that the weight on the wheel is decisive in the watts that you consume per kilometer, so a road bike will have less consumption in watts per kilometer than a mountain bike.One wheel 20 w/h vs 40 w/h.....

The release of energy in one hour depends on voltage which is the capacity and amperage that is the flow rate during that hour to release energy
..

converse

1 w/hour (unit work)(1w x 3600 second) = 3600 watts/second
500w/hour(unit work) (1wx 3600second) =1.800.000 watts /second

 

[Johnny]

Bosch ebike calculator is a very nice tool for most cyclists. However it is not accurate on the higher speeds and some parameters are quite ambiguous. For example rider input is 5 bars but honestly I don't know what each bar means likewise I don't know what light breeze or hilly terrain exactly refer to.

If we just made the computation wrt to the nominal output, the worst case mileage would be somewhat easy to compute. At a nominal output of 250W ,going 25mph would equate to 10wh/mile in the worst case but with a very significant rider effort.
Fwitw on a 2 mile stretch, mostly flat, little wind I was riding around 27mph, custom modes at %60 support. Nyon showed around 10-11wh/mile usage with 400+W rider input. I don't know about the accuracy of my input(I was sprinting alright, I enjoy it but that is not something I like to do when commuting) but the battery usage seemed accurate. While accelerating I can easily see 25-30wh/mile and it is certainly peaking in those instances but I have never pushed it continuously around those levels.

If only there was a technical document available for one of these motors it would have been easy to know what to expect.

 

[Stefan Mikes]

One wheel 20 w/h vs 40 w/h.....

I never heard of W/h.

It's like when I told you that the weight on the wheel is decisive in the watts that you consume per kilometer, so a road bike will have less consumption in watts per kilometer than a mountain bike.One wheel 20 w/h vs 40 w/h.....

• First of all @Manu it is good that you finally recognised Wh. I hope you already understand that power demand does not translate automatically to energy use, the latter depending on how long the rider maintains given speed.
• The talk about the role of the weight of wheels is complete bullshit. Two wheels may weigh several kilograms, while the rider and the bike together may well weigh more than 100 kg.
• You probably misinterpret the role of wheels. It is not wheel weight that matters but their rolling resistance. Rolling resistance depends among others on the tyre type (slick road tyre vs heavily grooved MTB tyre or fat tyre) and of the type off terrain (good tarmac vs sand). Rolling resistance matters the most for speeds up to 15 km/h.
• The second most serious factor is the air resistance, that requires more power the faster the bike rides, in the cubic power with growing speed.
• The third most serious factor is the terrain grade. The steeper the terrain becomes, more power is needed to maintain given speed.
• Now, let us look at the good power calculator.

Bike Calculator

Useful calculators for estimating your speed on a bicycle velocity from various parameters.

bikecalculator.com

Let us assume weight of rider 100 kg, bike weight of 24 kg, flat terrain, no wind, summer. Let us assume the rider can maintain 25 km/h and will ride for 1 hour:

The total power demand will be 188 W. A leisure rider will provide let us say 58 W with his legs, so the motor has to provide 130 W. With efficiency 80%, the power drawn from the battery will be 130/0.8 = 163 W. For 1 hour, that will be 163 Wh. As the rider covered 25 km, the consumption figure will be 163/35 = 6.5 Wh/km.

Now, let us increase the speed to 40 km/h. Oh! The power demand would be 503 W! Assuming that the motor in the Turbo mode can provide 450 W, the rider would pump continuously as much as 53 W with their legs to keep at that speed. Efficiency 80%, so 450/0.8 = 563 W battery power demand. The ride is 40 km, taking 1 hour, therefore energy consumption will be 563 Wh and when divided by 40 km, that would be 14 Wh/km.

Of course, if there is headwind and/or inclines or poor quality road, the consumption figures will rise significantly.

• Finally, add extra 4 kilograms to the bike weight for two heavy wheels. The power demand rose with 5 W, not with 40 W.