My experience with 32:34 is coherent with http://www.bikecalc.com/speed_at_cadence and gives between 9 and 10 km/h at cadence, seated, on a hill with +10% gradients the motor drawing less than 200 W most of the way!

 

Air resistance: 2.9 W/km for the Quest(!) @ 40 km/h I am guessing that more than compensates for the extra weight of the vélomobile but it does only weigh as much as many e-bikes on the market.

 

The new 1.4 kg xiongda coupled with a pinion C1.9xr correctly geared would take care of the weight on the hills, a 3 speed derailleur/freewheel combination with 18, 22 and 26 teeth would expand the already good 569% range quite handily! Imagine a motor + gearbox weighing about 3.8 kg (including freewheel)...

.. just curious but where do you get that wind loss figure?

That's all correct, though the words you used could be a bit misleading to some. All motors have a speed at which they're most efficient, but the efficiency curve is broad, so you can deviate a lot from the optimum efficiency speed without it making much difference. Here's a graph of an Ezee motor running with 15 amps. Look at the efficiency curve. efficiency is above 60% all the way from 5mph to 32 mph and above 70% from 9 mph to 31 mph.

Fair enough.

On an allied topic do you have information on the improvements to efficiency of brushless motors in ebikes by advances in controller design. Just curious, What I have in mind is whether it would be advantageous to dynamically increase or decrease the voltage from the battery by incorporating a smpsu into the controller. Similar tricks were done in some class d audio amplifiers in the past.

This means that massively low ratio gears can be fitted so that they can go up walls (exaggeration)., Slowly.!!!

 

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

Edited July 16, 20178 yr by EddiePJ

Here's a graph of an Ezee motor running with 15 amps. Look at the efficiency curve. efficiency is above 60% all the way from 5mph to 32 mph and above 70% from 9 mph to 31 mph.

are you sure?

why is it that I thought the Ezee motor has a noload speed at about 26-27mph?

.. just curious but where do you get that wind loss figure?

 

This guy over on ES ran a Quest model through his aerodynamics software I think? He did the Elf and his own two designs too.

 

https://endless-sphere.com/forums/viewtopic.php?f=28&t=62827&sid=99cc54764ea3deb3e1a5e60eaa5e6415&start=275

Fair enough.

On an allied topic do you have information on the improvements to efficiency of brushless motors in ebikes by advances in controller design. Just curious, What I have in mind is whether it would be advantageous to dynamically increase or decrease the voltage from the battery by incorporating a smpsu into the controller. Similar tricks were done in some class d audio amplifiers in the past.

I think motor efficiency depends more on the laminations connecting the magnets and how it's wound. There's some tricks you can do with the timing, like running VVT in a car, that can get more speed out of the motor than it would normally give, but that's all beyond my working knowledge.

 

Somebody on ES came up with something that could change the timing on the fly recently (a couple of months ago). I can't remember the details, but it didn't get a massive response.

are you sure?

why is it that I thought the Ezee motor has a noload speed at about 26-27mph?

There's loads of different Ezee motors including a cassette one now.

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

.. that looked exciting, I'm not into MTB , but that could tempt me...!

I think motor efficiency depends more on the laminations connecting the magnets and how it's wound. There's some tricks you can do with the timing, like running VVT in a car, that can get more speed out of the motor than it would normally give, but that's all beyond my working knowledge.

 

Somebody on ES came up with something that could change the timing on the fly recently (a couple of months ago). I can't remember the details, but it didn't get a massive response.

I came accross some postings somewhere about having multiple windings in each of the coils and then switching them from series to parallel,depending on the speed , giving the effect of low speed and high speed windings as required. That is an innovation which would increase the efficiency band for hubs.

I can't imagine much more being done with laminations. They have been optimising the magnetic paths for100 years. .. but then I have been proved wrong before.

That's switching the windings from delta to wye. They do that it some large traction motors. It's often discussed, but nobody uses it. It might be because the wiring and switching is too complicated for an e-bike, but i guess it's because it doesn't really work at our power levels.

are you sure?

why is it that I thought the Ezee motor has a noload speed at about 26-27mph?

Just for fun, I reset the CA and raised the speed limit on a bike I have with a 5 year old V2 eZee 250RPM front wheel motor with the standard eZee 20amp controller at 48v.

I did a static test to see what the max no load speed was and got 34.1 MPH, yes that's MPH not Km/h.

Of course I would only ever ride this on my private estate where the public has no access:rolleyes:

 

There are several variants of the eZee V2 motor i.e. front or rear, 200, 250, 300 and 350 RPM and of course the higher the RPM the lower the torque.

 

The eZee motor is a fantastic piece of kit used in several applications, not just electric bikes Germany's top selling cargo bikes and trikes use the eZee kits to haul loads in excess of 300Kg and sell them all over Europe, Spain's Batec Mobility use them in their handcycles.

Just for fun, I reset the CA and raised the speed limit on a bike I have with a 5 year old V2 eZee 250RPM front wheel motor with the standard eZee 20amp controller at 48v.

 

I was thinking about 36V.

I was thinking about 36V.

The same set up at 36v gives no load speed of 27.4MPH so your initial estimate was very close.

That's switching the windings from delta to wye. They do that it some large traction motors. It's often discussed, but nobody uses it. It might be because the wiring and switching is too complicated for an e-bike, but i guess it's because it doesn't really work at our power levels.

.. could be , I hadn't thought of that

That's switching the windings from delta to wye. They do that it some large traction motors. It's often discussed, but nobody uses it. It might be because the wiring and switching is too complicated for an e-bike, but i guess it's because it doesn't really work at our power levels.

Could be a y delta, didn't think about that, I thought it was more about switching parallel coils into series, in each of the 3 phases, anyway just a thought in passing.

I've got a Crossfire-e and I'm 100kg. I can ride a flattish circular route with 1 big hill and a few smaller ones, which is 45 miles in length, and I return with about 20% battery remaining. At all times I am in the lowest setting (eco/camel). Sometimes I am peddling on the flat over the 15.5mph therefore I am using no battery, but it's all comfortable going. I consider myself to be reasonably cycle fit, in that I can ride a hybrid non powered bike for 45-55 miles in a day (up to 6-7 hours rides).

So, certainly the claimed 60 mile range of the Crossfire-e is definitely realistic possibility, and not far off the mark if you are like me (maybe that remaining 20% could get me another 10 miles as it drops off when near empty)

For the record, I run narrowish (700c x 35) Energizer tyres at about 80 psi, which might roll a bit better than the wider stock Kenda tyres

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...

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

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

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.

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.

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

 

I found this interesting image:

 

[ATTACH=full]20281[/ATTACH]

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..

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..

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.

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 .

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!!!.