Speed vs battery life

[Mr. Coffee]

This raises an interesting question I might look into: Does a rider have any control over her own cycling efficiency?

Control from ride to ride seems unlikely, but how about limited long-term control through some kind of training program?

Sort of. But it is hard to know precisely.

You are likely to be most efficient at fairly low levels of effort and a low heart rate. For those in the know you reach peak efficiency if your heart rate is in "Zone 2". The very approximate rule of thumb is that you are in Zone 2 or lower if you can comfortably maintain a conversation while engaged in an activity. Absent complex lab tests it is challenging to be much more accurate than that.

If you are in better shape your Zone 2 power output will be higher. But if your heart rate is out of Zone 2 you are burning straight up sugars (mostly from your liver) and (1) you can't maintain that for very long, and (2) it is much less efficient. So generally at higher power power outputs your body will be less efficient. And if you are in a massive grind crank up a steep hill you will be the least efficient of all.

Also, if you aren't feeling well, are dehydrated, or are bonking your efficiency can go way down. And by "way down" I mean well below the 19-25 percent figures being tossed around in this forum. It is hard to know precisely but it is easily imaginable that your efficiency might go down below ten percent if you sweated out two liters of water -- which when riding hard on a warm day you might do in a couple of hours.

https://www.rei.com/learn/expert-advice/how-to-train-with-a-heart-rate-monitor.html

Target Heart Rate Calculator

Maximum heart rate calculator and exercise target heart rate zone calculator. Calculate exercise target heart rate zones using basic or Karvonen formulas. The 5 exercise zones calculated are VO2 Max, Anaerobic, Aerobic, Fat Burn and Warm Up heart rate zones.

www.calculatorsoup.com

How to avoid bonking on a bike ride

Essential tips to prevent that sudden, catastrophic loss of energy

www.bikeradar.com

 

[mschwett]

I'm learning a lot too. My interest is understanding my range riding my bike in different circumstances. With two separate energy sources it's not nearly as straightforward as X miles in assist level Y.

very true. the two most significant factors are speed, and rider input. if you keep speed down and have a bike in which more human power doesn’t always mean more motor power, and ideally means less, you can really ride VERY far!

 

[mschwett]

Sort of. But it is hard to know precisely.

You are likely to be most efficient at fairly low levels of effort and a low heart rate. For those in the know you reach peak efficiency if your heart rate is in "Zone 2". The very approximate rule of thumb is that you are in Zone 2 or lower if you can comfortably maintain a conversation while engaged in an activity. Absent complex lab tests it is challenging to be much more accurate than that.

If you are in better shape your Zone 2 power output will be higher. But if your heart rate is out of Zone 2 you are burning straight up sugars (mostly from your liver) and (1) you can't maintain that for very long, and (2) it is much less efficient. So generally at higher power power outputs your body will be less efficient. And if you are in a massive grind crank up a steep hill you will be the least efficient of all.

Also, if you aren't feeling well, are dehydrated, or are bonking your efficiency can go way down. And by "way down" I mean well below the 19-25 percent figures being tossed around in this forum. It is hard to know precisely but it is easily imaginable that your efficiency might go down below ten percent if you sweated out two liters of water -- which when riding hard on a warm day you might do in a couple of hours.

very good points. i will point out though that a moderately trained rider can sustain zone 3 for quite a while really - most estimates of human glycogen stores are in the 2,500 calorie range, so that’s 50+ miles for most. for me this is a rare case where the science aligns exactly with the practice - up to a three hour ride, 50 miles at 16-18mph, i don’t need to eat anything. beyond that without fueling during the ride and the bonk is ON.

 

[Stefan Mikes]

@mcdenny,
These are the factors affecting the energy consumption on a bike:

• The ride speed related to the power needed to overcome the air drag. Fast ride means short range
• The tyres used, proper/improper tyre inflation, type of the terrain ridden (rolling resistance). Asphalt rides on proper tyres mean long range. Off-road, knobby (and especially fat) tyres mean short range
• Potential energy gain/loss. You together with your motor need to spend a lot of energy for climbing; that is directly affected by the total system weight (rider + bike + cargo). You can recuperate a great deal of the potential energy on descents if you do not brake too much, do not pedal, and assume a forward position. However, the descent speed can be very high and dangerous; any braking on a descent means irreversible loss of your range.
• Kinetic energy gain/loss, which uses your + battery energy to accelerate and decelerate (braking). Multiple stops on the ride mean shorter range. Note: heavy wheels (like fat tyres) steal huge amount of battery energy for acceleration!

Now, as @mschwett correctly stated, it is all really down to these two factors: how fast you are willing to ride and how much of your own leg input you are ready to provide yourself. The electric assistance is just like a prosthetic here.

Three real life examples, based on the three degraded Vado 604 Wh batteries I own with the actual max charge of 533, 517, and 500 Wh respectively:

• A reasonably fast ride on the flat gives me roughly speaking 40 miles of range if I use the 40/40% full power Vado assistance.
• Now, I used Smart Control for my Vado with the 533 Wh battery on my 63 mile, 900 ft elevation gain ride of yesterday. The system was using 25% assistance for most of the trip which made it a slow ride with a good workout for me. 9% battery charge left at the ride end. I contributed to that ride in almost 50%!
• A mountain ride of 77.7 miles and 5,000 ft of elevation gain. It was a BLEvo metered ride: the average assistance was 54.1%, battery consumption was 981 Wh, the consumption factor was 12.6 Wh/mi. I contributed to the ride in 26%. Many ascents had to be taken in Turbo but then I was not using the battery on long descents and was avoiding braking.

I hope that helps.

 

[Jeremy McCreary]

Sort of. But it is hard to know precisely.

You are likely to be most efficient at fairly low levels of effort and a low heart rate. For those in the know you reach peak efficiency if your heart rate is in "Zone 2". The very approximate rule of thumb is that you are in Zone 2 or lower if you can comfortably maintain a conversation while engaged in an activity. Absent complex lab tests it is challenging to be much more accurate than that.

If you are in better shape your Zone 2 power output will be higher. But if your heart rate is out of Zone 2 you are burning straight up sugars (mostly from your liver) and (1) you can't maintain that for very long, and (2) it is much less efficient. So generally at higher power power outputs your body will be less efficient. And if you are in a massive grind crank up a steep hill you will be the least efficient of all.

Also, if you aren't feeling well, are dehydrated, or are bonking your efficiency can go way down. And by "way down" I mean well below the 19-25 percent figures being tossed around in this forum. It is hard to know precisely but it is easily imaginable that your efficiency might go down below ten percent if you sweated out two liters of water -- which when riding hard on a warm day you might do in a couple of hours.

https://www.rei.com/learn/expert-advice/how-to-train-with-a-heart-rate-monitor.html

Target Heart Rate Calculator

Maximum heart rate calculator and exercise target heart rate zone calculator. Calculate exercise target heart rate zones using basic or Karvonen formulas. The 5 exercise zones calculated are VO2 Max, Anaerobic, Aerobic, Fat Burn and Warm Up heart rate zones.

www.calculatorsoup.com

How to avoid bonking on a bike ride

Essential tips to prevent that sudden, catastrophic loss of energy

www.bikeradar.com

Excellent break-down!

Having been out of cycling for 25 years, I was familiar only with the British meaning of "bonk" and couldn't understand for the life of me why everyone here was so dead-set against bonking on rides.

I mean, some things are more important than getting there in record time.

 

[Stefan Mikes]

why everyone here was so dead-set against bonking on rides.

"It all stays inside the family" said a female cyclist not once on a ride Not that I exploited that possibility!

 

[PSm]

I'm learning a lot too. My interest is understanding my range riding my bike in different circumstances. With two separate energy sources it's not nearly as straightforward as X miles in assist level Y.

It’s so user and bike dependent, with so many variables, it’s really suited to your own experimentation.

Fun experiment I recommend people try:
- get up to speed on roughly level ground, preferably 15 mph or so
- try to maintain a consistent pedal output
- start from an upright riding position, and then try to get into a more aero position (head and upper body arched down toward your stem/handlebars)
- watch your real time speed go up, as if by magic

For more experiments:
- do the same, at different PAS levels
- do the same, going downhill

 

[mcdenny]

Finally got my longer ride in today. Riding 24 miles was not hardly different from my 6 mile test loop rides. My conclusion is that my ass and shoulder range is substantially less than the battery range!

Pretty flat compared to my test loop.

I rode one way in ECO mode 98% of their time, shifting as necessary to keep cadence around 70. The other way I pretty much left it in fifth gear (70 rpm = 14 mph) and used SPORT and TURBO as necessary to keep the same 70ish cadence.

If anyone is reading this in the Nashville area I highly recommend the Stones River Greenway in Murfreesboro. Really scenic and lots of civil war historic sites.

 

[Mr. Coffee]

... most estimates of human glycogen stores are in the 2,500 calorie range, so that’s 50+ miles for most. for me this is a rare case where the science aligns exactly with the practice - up to a three hour ride, 50 miles at 16-18mph, i don’t need to eat anything. beyond that without fueling during the ride and the bonk is ON.

But even someone who is whippet-thin probably has 10k calories stored as fat, and most of the readers of this forum are considerably well-padded and probably are storing four or five times that.

Also in practice at any given time and output level your body is burning a combination of glycogen and fats, with more glycogen at higher power output and more fats at lower power outputs.

Everybody is different. My own experience is that for anything over about ninety minutes, I should be eating a small amount every hour or so. So on a long day in the saddle there isn't really a "lunch" and often no identifiable "breakfast", just a series of snacks from predawn coffee to tiffin.

 

[Stefan Mikes]

My conclusion is that my ass and shoulder range is substantially less than the battery range!

If you practice more and more longer rides, you should get used to it I spent the first six months of my e-biking on relatively short rides, gradually extending my distance until I made the first Metric Century (I needed an extra battery for that). Now, a 40 or 50 mile ride is a norm for me, with the Metric Century (62 miles) happening quite often, and my rides have also included two Imperial Centuries (100+ mile).

 

[Mr. Coffee]

If you want to build up endurance:

• Focus on riding at fairly aerobic pace. You should be able to maintain a conversation while you ride.
• Think in terms of hours riding, not distance.
• It is better to ride a little bit most every day than to have two or three big rides a week.
• Get a bike fit.
• If you are just plain tired having a rest day is no sin. As you get stronger those "rest days" can turn into "active rest" or "cross training".

If after doing the above for several weeks, you want to go faster, consider some more intense training ideas. One simple one is just "sessioning" a hill. Find a hill of appropriate length and grade, and crank up it pretty hard (hard enough that you can't speak in complete sentences) and blast back down. Repeat. Depending on how strong you are that hill might be a half kilometer or four or five kilometers. Up to you really.

If you do the more intense stuff the rest days become more important.

Also after a big day, or at least a relatively big day, have a lighter day the next day. Again that may be full-on rest, active rest, cross training, or a short recovery ride.

 

[PSm]

If you want to build up endurance:

• Focus on riding at fairly aerobic pace. You should be able to maintain a conversation while you ride.
• Think in terms of hours riding, not distance.
• It is better to ride a little bit most every day than to have two or three big rides a week.
• Get a bike fit.
• If you are just plain tired having a rest day is no sin. As you get stronger those "rest days" can turn into "active rest" or "cross training".

If after doing the above for several weeks, you want to go faster, consider some more intense training ideas. One simple one is just "sessioning" a hill. Find a hill of appropriate length and grade, and crank up it pretty hard (hard enough that you can't speak in complete sentences) and blast back down. Repeat. Depending on how strong you are that hill might be a half kilometer or four or five kilometers. Up to you really.

If you do the more intense stuff the rest days become more important.

Also after a big day, or at least a relatively big day, have a lighter day the next day. Again that may be full-on rest, active rest, cross training, or a short recovery ride.

^ this ^
One of the best things about having an e-bike is that it’s perfect for a “recovery day” ride, at higher assist. After an intense analog traditional bike ride, can get in a good recovery day e-bike ride in, to keep the legs moving without overdoing it. Or, same if after doing an intense e-bike ride for fitness and training.

 

[mschwett]

But even someone who is whippet-thin probably has 10k calories stored as fat, and most of the readers of this forum are considerably well-padded and probably are storing four or five times that.

Also in practice at any given time and output level your body is burning a combination of glycogen and fats, with more glycogen at higher power output and more fats at lower power outputs.

Everybody is different. My own experience is that for anything over about ninety minutes, I should be eating a small amount every hour or so. So on a long day in the saddle there isn't really a "lunch" and often no identifiable "breakfast", just a series of snacks from predawn coffee to tiffin.

yeah, it’s definitely an oversimplification to say you’re burning one or the other, but my understanding is that it takes quite a while, at relatively low intensities, to do any serious fat burning.

 

[mcdenny]

My last data point I will bore you with. Today I rode in Percy Warner park, just west of Nashville. Mostly forest with lots of steep hills, so steep that I was pedaling up in second or third gear and TURBO mode, maybe 10 mph. The asphalt was old and sun dappled so it was hard to read the surface. As a consequence I was on the brakes going down wasting all that potential energy.

Today was 1300' elevation in 15 miles. Yesterday was 470' in 24 miles. Average speed was not very different and neither was my watts pedaling. The difference was the terrain and my needing to brake coasting downhill. The battery would have lasted 76 miles on yesterdays flattish ride but only 46 miles on todays hilly ride. What is the range of Turbo Como 3.0? It varies!

Gratuitous pic of me at the scenic lookout. Nashville skyline in the background.

 

[mschwett]

nice pic and nice ride! i bet you’d get 10% more range at speeds over 10-12mph with a more aerodynamic carrying solution for your bag!

 

[mcdenny]

nice pic and nice ride! i bet you’d get 10% more range at speeds over 10-12mph with a more aerodynamic carrying solution for your bag!

Probably but I like having that big trunk.

 

[Stefan Mikes]

May 3rd 2023 meant a 75 mile ride for me. No pain or aches whatsoever but it took me 3 years to come to that experience
And a recovery day on May 2nd was a necessary thing to have.

 

[PSm]

yeah, it’s definitely an oversimplification to say you’re burning one or the other, but my understanding is that it takes quite a while, at relatively low intensities, to do any serious fat burning.

View attachment 152915

For really high intensity exercise (near my limit), I’ve found that I need a guu gel and/or a nutritional bar every ~45 minutes to an hour, and regular hydration, to not bonk and have legs/knees/calves major fatigue and recovery needed. This is for longer rides, with a fast group or solo climbing, 2-3 hours or for gran fondos.

For lower intensity rides 1-2 hours or so, though not ideal, I can have no water or nutrition at all, and still be okay for the ride. YRMV.

 

[Kilowatt]

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.

Power required to overcome wind resistance is proportional to the cube of velocity. Double your speed, and power increases 8 times.

 

[dodgeman]

I just googled it and it said square of your speed. It’s probably not that simple because it’s possible and certain speeds the air flow is laminar where at a different speed it might be turbulent.