Battery life v Weight and Terrain

[anotherkiwi]

D8ve is no longer here so someone has to take up the "bent" banner

I found this interesting image:


The average bent rider is offering about as much frontal area as a competition rider tucked up into aero position on a road bike. This will affect both top speed and battery range, D8ve was getting obscene range from his battery when riding bent. Now he is in a vélomobile and doesn't even need a motor See how the extreme competition bent (more like lying down than bent) only offers half the frontal area of an upright cyclist to the wind...

 

[Izzyekerslike]

Exactly, as my climb today shows.

https://www.strava.com/activities/1086419096/shareable_images/map_based?hl=en-US&v=1500217799

https://www.relive.cc/view/1086419096

And in relation to the battery, it was changed at about the 8.5 mile point of the climb. It isn't worth trying to climb/ use the battery once the battery level reaches one bar remaining. The power tails off too much, and it doesn't become a viable option. I also noted, just as I did last year when I completed the same climb, that the battery case becomes uncomfortably warm to the touch

 

[Izzyekerslike]

Are you still up there because there's no return trail? I was going to say great climb and amazing return.

 

[Deleted member 4366]

The average bent rider is offering about as much frontal area as a competition rider tucked up into aero position on a road bike. This will affect both top speed and battery range, D8ve was getting obscene range from his battery when riding bent. Now he is in a vélomobile and doesn't even need a motor See how the extreme competition bent (more like lying down than bent) only offers half the frontal area of an upright cyclist to the wind...

Good point, but that doesn't make much difference below 15 mph unless it's windy. I suspect it's more likely that D8ve got good range because he turned the power down and pedalled hard.

I expect to get a range of at least 50 miles from my 6Ah battery, not because the bike has a low frontal area but because I'll be pedalling it a lot without power, as it only weighs 12.5kg. I could put an AA cell powered Airfix motor on my road bike and drive the crank with a rubber band, then claim that it's the most efficient electric bike at 1 wh per 100 miles.

It's different if you travel at 20 mph or more with maximum power all the time. Even the type of trouser you wear makes a difference then.

 

[EddiePJ]

Are you still up there because there's no return trail? I was going to say great climb and amazing return.

I'd love to still be up there.

For the most part I have been recording the ascent and descent as two separate rides. I'm only interested in the climbing.

I completed my last ride today, which brought the total elevation gain to 63,168ft over a distance of 179 miles.Of that, 53.8 miles and 6,299ft of elevation gain doesn't count, as it was ridden on one ride using the pedal mtb. Sadly I fell way short on my expected elevation gain, but never mind.

 

[Danidl]

D8ve is no longer here so someone has to take up the "bent" banner

I found this interesting image:

View attachment 20281
The average bent rider is offering about as much frontal area as a competition rider tucked up into aero position on a road bike. This will affect both top speed and battery range, D8ve was getting obscene range from his battery when riding bent. Now he is in a vélomobile and doesn't even need a motor See how the extreme competition bent (more like lying down than bent) only offers half the frontal area of an upright cyclist to the wind...

.. that's a lovely graphic..

 

[Danidl]

Good point, but that doesn't make much difference below 15 mph unless it's windy. I suspect it's more likely that D8ve got good range because he turned the power down and pedalled hard.

I expect to get a range of at least 50 miles from my 6Ah battery, not because the bike has a low frontal area but because I'll be pedalling it a lot without power, as it only weighs 12.5kg. I could put an AA cell powered Airfix motor on my road bike and drive the crank with a rubber band, then claim that it's the most efficient electric bike at 1 wh per 100 miles.

It's different if you travel at 20 mph or more with maximum power all the time. Even the type of trouser you wear makes a difference then.

.. it's always windy.. maybe not inland but coastal always.and it's always against one..

 

[anotherkiwi]

Good point, but that doesn't make much difference below 15 mph unless it's windy. I suspect it's more likely that D8ve got good range because he turned the power down and pedalled hard.

I expect to get a range of at least 50 miles from my 6Ah battery, not because the bike has a low frontal area but because I'll be pedalling it a lot without power, as it only weighs 12.5kg. I could put an AA cell powered Airfix motor on my road bike and drive the crank with a rubber band, then claim that it's the most efficient electric bike at 1 wh per 100 miles.

It's different if you travel at 20 mph or more with maximum power all the time. Even the type of trouser you wear makes a difference then.

The Russian who made the image says that even at 25 km/h and below air resistance is significative, it is our perception that makes us only start to feel it at 30 km/h and above. Then if you add the head wind factor it is even more significant below 25 km/h, you only need a 20 km/h head "breeze" to hit the "wall" of resistance which is about 45-47 km/h.

 

[ElectricOwl]

You need a double or triple chainring to climb hills without power from the motor or with low power.

Went out last night and did about 23 kilometres I really pushed myself using the gears and keeping in the lowest gear possible and yes I significantly increased my battery life but when I was going up a decent hill without battery and in the lowest gear I nearly came to a standstill , it actually felt the brakes were on and I would have definitely stopped without switching the power on .

 

[Danidl]

The Russian who made the image says that even at 25 km/h and below air resistance is significative, it is our perception that makes us only start to feel it at 30 km/h and above. Then if you add the head wind factor it is even more significant below 25 km/h, you only need a 20 km/h head "breeze" to hit the "wall" of resistance which is about 45-47 km/h.

The most telling one is that wind resistance power loss increases by the cube of the speed . It is the total air speed that matters . Eg a person travelling at 10 kmhr into or against a wind speed of 5 km HR.. barely noticeable when stopped will have either 15 or 5 km HR apparant wind. The power loss in case 1. Is a whopping 27 times more!!!.

 

[anotherkiwi]

The other day I crossed the bridge (flat as a pancake) into a stiff westerly and was topping out at 20 km/h in assistance level 5 of 5! At the moment I am working very hard at dividing my frontal area by 2

 

[Kinninvie]

I wonder if one of those see through umbrellas might help?

Worryingly my search for plastic see through u Returned "plastic see through underwear" !!!

 

[topographer]

Why don't people use handlebar fairings? It's not like there's a big obvious drawback is there?

 

[Danidl]

Why don't people use handlebar fairings? It's not like there's a big obvious drawback is there?

Sidewinds . One is not always going against the wind.

 

[topographer]

Sidewinds . One is not always going against the wind.

Oh.

 

[anotherkiwi]

Sidewinds . One is not always going against the wind.

Well actually... You are. Even when the wind is coming from behind you create your own headwind. A tail fairing is probably more efficient in reducing drag tucked down on aero bars you are about as aerodynamic as you can get. Sidewinds have a role on an upright bike too.

Check out streamliner bikes @topographer

 

[topographer]

Perfecto.

 

[Danidl]

Well actually... You are. Even when the wind is coming from behind you create your own headwind. A tail fairing is probably more efficient in reducing drag tucked down on aero bars you are about as aerodynamic as you can get. Sidewinds have a role on an upright bike too.

Check out streamliner bikes @topographer

I don't know where you cycle, but in my coastal location, the wind can gust quite badly and change direction at a whim. Bikes with fairings are just as lightly to have the wind coming at any odd angle as either a headwind or a tailwind. A side wind would catch the fairing as a sail could easily move the bike and cyclist into either a ditch or ongoing car traffic.
The BMW roofed motorcycle and other similar designs work because it is much more massive (heavier) than a bike

 

[Deleted member 4366]

I think there's some merit in fairings for e-bikes. A few years back, some guys knocked up fairings out of that corrugated plastic sheet, and reported good results.

I reckon that it's more the weight penalty that puts people off because the main problem on a bicycle is going up hills. I think a lot of people would be happy to sacrifice a couple of mph on top speed if they could have easier climbing. It might be different, though, for people living in North Holland, where it's flat and you get a lot of wind.

When you wear a cape/poncho in the rain, the gusting side-winds would have much more effect than a on a fairing. They're a nuisance at first, but you soon get used to it and learn to deal with it. I don't see it as a major problem.

I think the reaction to crosswinds has more to do with steering geometry than mass. I've had very light motorcycles like Suzuki RGV that were rock steady in all conditions, while as much heavier ones Yamaha FZ600 would struggle to stay in their lane on a motorway. Unfortunately, it's not easy to change a bicycle's geometry to adapt it for a fairing. Like motorbikes, there's probably some that would be a lot less affected than others.

 

[topographer]

I think there's some merit in fairings for e-bikes. A few years back, some guys knocked up fairings out of that corrugated plastic sheet, and reported good results.

I reckon that it's more the weight penalty that puts people off because the main problem on a bicycle is going up hills. I think a lot of people would be happy to sacrifice a couple of mph on top speed if they could have easier climbing. It might be different, though, for people living in North Holland, where it's flat and you get a lot of wind.

When you wear a cape/poncho in the rain, the gusting side-winds would have much more effect than a on a fairing. They're a nuisance at first, but you soon get used to it and learn to deal with it. I don't see it as a major problem.

I think the reaction to crosswinds has more to do with steering geometry than mass. I've had very light motorcycles like Suzuki RGV that were rock steady in all conditions, while as much heavier ones Yamaha FZ600 would struggle to stay in their lane on a motorway. Unfortunately, it's not easy to change a bicycle's geometry to adapt it for a fairing. Like motorbikes, there's probably some that would be a lot less affected than others.

I was thinking about distance more than speed. I'd like to see proper experimentation and research done into motorbike style body panels on ebikes. Maybe it's not worth it but I'd like to see proof either way.