Speed vs battery life

[Jeremy McCreary]

You seem to have forgotten the fourth resistance Jeremy, which is the kinetic energy loss on stopping/restarting the ride.

Didn't forget, just focusing on the constant ground speed case — which is roughly where most of us ride most of the time. Should've made that clear.

Yes, linear and rotational inertias are important for responsiveness in braking, acceleration, and turning. That's where total mass and wheel moment of inertia really count. Working on a separate set of graphs to tell that part of the story.

 

[fooferdoggie]

Didn't forget, just focusing on the constant ground speed case — which is roughly where most of us ride most of the time. Should've made that clear.

Yes, linear and rotational inertias are important for responsiveness in braking, acceleration, and turning. That's where total mass and wheel moment of inertia really count. Working on a separate set of graphs to tell that part of the story.

I net I lose 20 miles or range commuting verses just going for a long ride.

 

[circuitsmith]

It would be interesting to see if you can get a few more miles per charge by reducing your speed by 3 or 4 mph.

Back to the original question, yes, of course going slower and using less motor will increase range.
Drastically, if you don't go much faster than you would without the assistance, only use it to maintain speed on hills etc.

I actually enjoy getting away from calculation, test & measurement when riding the bike.
Did enough of that at work.
At first I intentionally avoided putting even a voltage display on my old Currie USPD.
Didn't want to risk the distraction.
Broke down and added one after switching to NiMH batteries, because it was harder (than with lead-acid) to judge battery level by feel.

 

[mcdenny]

I really do not want to analyse it. It does not help anyone just to convert the kcal to Wh because there also is the efficiency of the human body which is 20-25% depending on the assumption. Also, the Mission Control figures are not comprehensive.

If you could upload some of your rides to Strava @mcdenny then Strava converts the data from Mission Control (or Wahoo or Garmin as connected to a Specialized e-bike) and it comes with own kcal values, which is something we could compare (I use Wahoo/Strava for my rides not Mission Control).

Is the kcal data from Mission Control not reliable? Seems it must know the power (torque I provide, pedal rpm) and duration to compute energy.

 

[Mr. Coffee]

Efficiency values (for converting from your output Wh to your input kcal) vary quite a bit and often in bewildering ways. So just throwing out a number or a range (e.g. 20-25%) isn't actually helpful. Your overall physical condition, your gender, how hydrated you are, and how much power you are putting out all have a measurable impact on that conversion. Absent lab testing it is hard to know where you are in the spectrum.

Cycling Efficiency in Trained Male and Female Competitive Cyclists

The aim of this study was to examine differences in cycling efficiency between competitive male and female cyclists. Thirteen trained male (mean ± SD: 34 ± 8 yr, 74.1 ± 6.0 kg, Maximum Aerobic Power (MAP) 414 ± 40 W, VO[2] ...

www.ncbi.nlm.nih.gov

 

[Stefan Mikes]

Is the kcal data from Mission Control not reliable? Seems it must know the power (torque I provide, pedal rpm) and duration to compute energy.

It is not the data is not reliable *but please read what Mr. Coffee wrote*. What is wrong in Mission Control is it is giving your kcal -- which is an arbitrary value involving assumed body efficiency -- but the app should give Wh/mi or Wh/km -- which is a measured figure from the e-bike sensors. The application BLEvo that only works with Gen 1 Specialized motors gives Wh/distance unit.

BLEvo tells me I contribute with some 25% to 30% energy into my Vado 6.0 rides. I expect you contribute with 50-60%, and that's a huge difference regarding the battery range!

Uploading Mission Control or Wahoo ride data to Strava gives average leg power in Watts, and that is something we could compare.

 

[mcdenny]

It is not the data is not reliable *but please read what Mr. Coffee wrote*. What is wrong in Mission Control is it is giving your kcal -- which is an arbitrary value involving assumed body efficiency -- but the app should give Wh/mi or Wh/km -- which is a measured figure from the e-bike sensors. The application BLEvo that only works with Gen 1 Specialized motors gives Wh/distance unit.

BLEvo tells me I contribute with some 25% to 30% energy into my Vado 6.0 rides. I expect you contribute with 50-60%, and that's a huge difference regarding the battery range!

Uploading Mission Control or Wahoo ride data to Strava gives average leg power in Watts, and that is something we could compare.

Hmmm. I’ll give Strava a try tomorrow.

 

[mschwett]

Hmmm. I’ll give Strava a try tomorrow.

the mission control rider power data is the same as what Strava will show - Strava takes it directly from the mission control recording. the calorie estimates will be slightly different because they use slightly different models for the efficiency of the body.

if your bike does NOT have a power meter, Strava will make up some BS which is (in my experience) completely wrong. Strava has no idea what tire pressure you rode, how fat your tires are, how aerodynamic you are, how rough the road was, whether there was a big headwind or not, etc etc etc. totally useless.

also worth noting that the power meter in the specialized e bikes is not exactly the same as a purpose built cycling power meter, and is definitely off by 5-10% in one way or the other depending on mysterious factors that specialized is not talking about lol.

 

[mschwett]

Wind resistance is roughly based on the square of your speed. This means if you double your speed the wind resistance goes up 4 times. Triple your speed and wind resistance goes up 9 times.

this comes up a lot - although it’s true that the wind resistance is the square of the speed, the power required to overcome it is actually the cube because if you’re going twice as fast, you encounter twice as much of it in a given time.

at low speeds, friction between tires and road are the biggest factor. at high speeds, wind resistance is the vast majority. this is why on many e-bikes, the harder you pedal, the less range you have, unless you also turn the motor power wayy down.

a good tool to experiment is http://bikecalculator.com/

it will tell you that to go 10mph an upright bike with fat tires it takes 80 watts. 15mph, 163 watts. 20mph, 300 watts. 40mph, 1700 watts. note that the jump from 20 to 40 is far more than 4x.

now let’s consider a much lighter bike and rider with less rolling resistance and less drag: 10 mph is a mere 34 watts. 15 mph, 82 watts. 20mph, 166 watts, and 40mph, 1100+ watts.

from Wikipedia:

"Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[16] With a doubling of speed the drag (force) quadruples per the formula. Exerting 4 times the force over a fixed distance produces 4 times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, 4 times the work done in half the time requires 8 times the power."

 

[Stefan Mikes]

the mission control rider power data is the same as what Strava will show

[I have deleted my irrelevant post content as I can understand what you are talking about now].

I think Mark you are opening the Mission Control rides with the Specialized Ride app. Yes, the adjusted rider power for my model ride is 80 W there. Now, @mcdenny can install the Specialized Ride app, open his model ride there and tell me what his leg power is!

 

[mschwett]

I think Mark you are opening the Mission Control rides with Specialized Ride app. Yes, the adjusted rider power for my ride is 80 W there. Now, @mcdenny can install the Specialized Ride app, open his model ride there and tell me what his leg power is!

yes, you’re right! mission control displays rider power as you ride, and records it, but does not display it in the ride summary. “ride” or strava - or any other gpx/tcx/fit file viewer will show it exactly as mission control recorded it.

the important thing to note is that if you upload from MC to strava, strava is not calculating this based on speed and weight and gradient, it’s just reading the values saved by mission control (or in your case saved by the wahoo.) the data matches.

strava - 212w average

ride - 212w average

calorie counting estimates vary quite a bit - 827 vs 924 for this short and flat ride.

 

[Stefan Mikes]

the important thing to note is that if you upload from MC to strava, strava is not calculating this based on speed and weight and gradient, it’s just reading the values saved by mission control (or in your case saved by the wahoo.) the data matches.

It is possible that the MC power data are just copied to Strava (like, 80 W).
However, with Wahoo as the medium between the e-bike and Strava, I'm getting 71 W (Weighted Avg Power) or 67 W (Avg Power) in Strava.
Perhaps it is because the Wheel Circumference as hard-coded in my Vado 6.0 is wrong while Wahoo has the true value for my rear wheel entered. (Hard-coded or read-only WhC because Specialized thought they would use a 2300 mm wheel but eventually used a 2255 mm wheel! As Vado 6.0 is a Euro moped, Type Approved values cannot be changed).

 

[Stefan Mikes]

strava - 212w average

As an aside note: Now I can understand why you need no motor!

 

[mschwett]

It is possible that the MC power data are just copied to Strava (like, 80 W).
However, with Wahoo as the medium between the e-bike and Strava, I'm getting 71 W (Weighted Avg Power) or 67 W (Avg Power) in Strava.
Perhaps it is because the Wheel Circumference as hard-coded in my Vado 6.0 is wrong while Wahoo has the true value for my rear wheel entered. (Hard-coded or read-only WhC because Specialized thought they would use a 2300 mm wheel but eventually used a 2255 mm wheel! As Vado 6.0 is a Euro moped, Type Approved values cannot be changed).

no, the power values output don’t depend on wheel circumference. strava also isn’t reading the “average” value from the data file - the file actually doesn’t contain an average, just the individual samples, recorded every second along with other data. the average calculation can be skewed quite a bit by strava’s or wahoo or specialized’s different method of determining whether the ride is stopped, by pausing mission control, etc. strava’s weighted average power is also a metric of their own choosing, different from normalized power or any number of other power figures.

when i had my creo connected by BOTH ant+ and bluetooth (bluetooth to mission control and ant+ to the cadence cycling app via a converter) i found that the data were shifted in time just enough to vary slightly. the later versions of mission control are also receiving much more than one data point per second (you can see the power number visibly changing much faster), whereas ant+ always seems to be only one update per second.

so, lots of very small differences but the big one will be attempting to determine an “average” when the time is not clearly defined. rides without stops match really, really closely, as in my example.

 

[Sparky731]

Per my experience, riding in Turbo mode sucks ~4x to 5x the amount of electrons as Eco mode.

 

[Zekeer]

Why has nobody factored in Fat . Like from ones body shape / Whether you have hair , firm muscles etc . I've made 100 miles averaging 14 MPH using the lowest % of my battery . Averaging 20 MPH with Factory default settings I easily get 45 miles if I push it I have got 51. That's on a 2020 Vado 4 . My buddy just bought a Brand New used 2021 Trek Alliant . While that bike has a Bigger Battery and is lighter then my Vado . My older Vado is built better . It definitely rolls smoother . The Axles are way way nicer . Add all that to him weighing 90lbs more then me. I get better mileage. When he first picked up the BRAND NEW Bike I thought I have to get one . After riding his, it made me like mine even more . Granted he has upgraded software / That's nice : But IMO it's not what matters . If I want to know all my vitals I'll have a Stress test done . JMO but I think all that stuff is gimmicky . Some of you may disagree . And that's fine I'll let you slide .

 

[Stefan Mikes]

Why has nobody factored in Fat . Like from ones body shape / Whether you have hair , firm muscles etc . I've made 100 miles averaging 14 MPH using the lowest % of my battery . Averaging 20 MPH with Factory default settings I easily get 45 miles if I push it I have got 51. That's on a 2020 Vado 4 . My buddy just bought a Brand New used 2021 Trek Alliant . While that bike has a Bigger Battery and is lighter then my Vado . My older Vado is built better . It definitely rolls smoother . The Axles are way way nicer . Add all that to him weighing 90lbs more then me. I get better mileage. When he first picked up the BRAND NEW Bike I thought I have to get one . After riding his, it made me like mine even more . Granted he has upgraded software / That's nice : But IMO it's not what matters . If I want to know all my vitals I'll have a Stress test done . JMO but I think all that stuff is gimmicky . Some of you may disagree . And that's fine I'll let you slide .

Not negating what you have said, I'd mention the e-bike battery degrades with the number of the recharge cycles; therefore an old e-bike will usually offer a shorter range to the same person than a new one even if that's the same make/model.

 

[Sparky731]

Not negating what you have said, I'd mention the e-bike battery degrades with the number of the recharge cycles; therefore an old e-bike will usually offer a shorter range to the same person than a new one even if that's the same make/model.

I will concur to established norms per battery life, but I have minimal degradation after 7k+ miles and 2 years of near-daily cycles to full each time. Maybe I have blinders on or I just don’t ride as hard lately. Given I ride mostly in Turbo (because it is more fun) I am used to frequent battery drains.

 

[AHicks]

I will concur to established norms per battery life, but I have minimal degradation after 7k+ miles and 2 years of near-daily cycles to full each time. Maybe I have blinders on or I just don’t ride as hard lately. Given I ride mostly in Turbo (because it is more fun) I am used to frequent battery drains.

It's a matter of knowing the bike. I have a battery that's several years old too, and the AVERAGE miles between charges hasn't change that much (yet!).

 

[mcdenny]

If you could upload some of your rides to Strava @mcdenny then Strava converts the data from Mission Control (or Wahoo or Garmin as connected to a Specialized e-bike) and it comes with own kcal values, which is something we could compare (I use Wahoo/Strava for my rides not Mission Control).

Just put the free version of Strava on my phone, very interesting seeing the graphs of elevation, speed and cadence. Thanks for the suggestion.

Did substantially the same test loop yesterday at my normal riding style - mostly ECO but SPORT or even TURBO going up hills. Coasting down hills.

Here's the comparison:
........................................................................Mission
........................................................................Control......Strava.....Strava
Distance....Avg Speed.....Time.....Batt used......kcal..........kcal........watts
6.6 miles....11.9 mph......33 min.....39 wh..........102..........116...........52

Using the Strava data: 52 watts for 33 minutes = 28.6 Wh. 116 kcal = 134.9 Wh.

Is the watts data just the pedaling energy while the kcal data includes pedaling energy plus resting energy used?

Our bodies use a lot of kcal just keeping us alive. A resting metabolic rate calculator https://www.omnicalculator.com/health/rmr says I use 1625 kcal/day doing nothing. That's 37 kcal in 33 minutes or 43 Wh. Doesn't look like Strava kcal = pedal energy + resting energy. ???

Another puzzling comparison:
Pedaling energy per Strava 28.6 Wh; Battery energy per Mission Control 39 Wh. Battery/me = 136%; Mission Control support level = 195%. ???