Leaf / leafmotor / leafbike high efficiency 1500w motor

[john61ct]

So your requirement is high torque (for climbing) and pretty good efficiency (for mitigating heat) at relatively low speed

Since the winding issue does not seem to help with the climbing long hills with heavy loads, nor help with heat / efficiency

The torque is needed just as much for frequent standing starts in stop-and-go city commuting

does the winding make any difference for that latter context?

Some have said "higher voltage is always better". I assume that is wrt a slight efficiency increase from less resistance of lower amps assuming the same gauge wiring?

 

[Balmorhea]

So your requirement is high torque (for climbing) and pretty good efficiency (for mitigating heat) at relatively low speed

Since the winding issue does not seem to help with the climbing long hills with heavy loads, nor help with heat / efficiency

The torque is needed just as much for frequent standing starts in stop-and-go city commuting

does the winding make any difference for that latter context?

Some have said "higher voltage is always better". I assume that is wrt a slight efficiency increase from less resistance of lower amps assuming the same gauge wiring?

Motor winding does make a difference in terms of the riding envelope available to you. In a start/stop scenario, more torque and a lower cruise speed/max efficiency rpm means you spend much less of the time in an inefficient range, and more in the sweet zone where the motor’s power tapers off at the top end. But it also means you go slower— good for efficiency and range, bad for jollies.

For long climbs, having enough torque and a low enough free speed to climb at 85-90% efficiency makes a huge difference in heating, versus climbing at 60% efficiency because your motor can’t get on top of its rpm range.

These things can be juggled around somewhat by using different voltage and current, but only up to the limits of the equipment (like phase wire gauge, or power switch voltage ratings) and the electrical components you actually have available.

 

[john61ct]

means you go slower— good for efficiency and range, bad for jollies

As mentioned, I care not for speed, get my jollies elsewhere.

> For long climbs, having enough torque and a low enough free speed to climb at 85-90% efficiency makes a huge difference in heating, versus climbing at 60% efficiency because your motor can’t get on top of its rpm range.

But does the winding actually affect those factors?

And do please check my understanding / vocabulary for high vs low fast vs slow etc above?

 

[Balmorhea]

For long climbs, having enough torque and a low enough free speed to climb at 85-90% efficiency makes a huge difference in heating, versus climbing at 60% efficiency because your motor can’t get on top of its rpm range.

But does the winding actually affect those factors?

It does if you constrain your battery and controller choices to the normal 36-52V range. When maximum torque is important, as when climbing steep grades, you will be using full throttle. If you have enough torque to climb at say 75 percent of the motor's free speed, it will run very efficiently and relatively cool. But if you let the thing bog down to 50% of its free speed because that's the only way to get enough torque, then you'll have poor efficiency and you'll burn your motor down.

If you have too fast a winding, you will have to use lower and lower voltage with increasingly untenable high currents to get the unloaded rpm low enough and the torque high enough.

MadRhino's and John in CR's method is to have so much surplus power that they can charge uphill at high speeds that are somewhat efficient (and not take very long doing it). But if dozens of HP aren't on your menu, you have to do more careful matching of load to motor speed, so you don't lug it down and overheat it.

Because winding is more arbitrary than any other element of the system, it makes sense to use the winding to do load and speed matching.

 

[John in CR]

> For long climbs, having enough torque and a low enough free speed to climb at 85-90% efficiency makes a huge difference in heating, versus climbing at 60% efficiency because your motor can’t get on top of its rpm range.

With a hubmotor you can get anywhere near that efficiency while climbing without a very large heavy motor, and on the flats they can get to the upper ranges of a motor's efficiency cruising at constant speed anywhere above about 50% of top speed. The notion of good efficiency only occurring only at the top end of the rpm range is faulty.

 

[John in CR]

But does the winding actually affect those factors?

No

 

[John in CR]

For long climbs, having enough torque and a low enough free speed to climb at 85-90% efficiency makes a huge difference in heating, versus climbing at 60% efficiency because your motor can’t get on top of its rpm range.

But does the winding actually affect those factors?

It does if you constrain your battery and controller choices to the normal 36-52V range.

Once again absolute nonsense. Higher speed windings actually make you able to run lower voltage and achieve identical results. Then later when you want higher performance, it's simple. Just increase the voltage and still end up within your "normal 36-52V range".

I started this journey in a serious manner in 2008 with 5 1200W hubmotors wound to a Kv of 16rpm/volt which came with 20A 60V controllers running motorcycle tires ranging from 20" to 24" in outside diameter. I live in a mountainous area and have always hauled heavier loads than typical. Guess how many motors I've ever burned up...exactly zero, even later after upping power to as high as 11kw peak input. Those motors are the same as the Leaf, but with 40mm stators (so 14% more torque potential) and the old .5mm stator lams, so they didn't have quite the peak efficiency of the Leaf.

 

[ZeroEm]

My trike has a 7t at 72v the torque gained over the 5t is 20nm, for the same amps, then it drops down to match 5t at 6 mph. No free lunch the 7T motor starts losing power and torque at 28 mph which is the speed limit and I have my speed limited to it.

The 7t is a good match for the way I ride with the setup.

the 5t leafmotor has the best copper fill so it should be the most efficient.

Link to my setup 7t vs 5t
https://www.ebikes.ca/tools/simulator.html?motor=Leaf%205T&batt=B7223_AC&cont=C40&frame=semi&mass=150&hp=25&cont_b=C40&motor_b=Leaf%205T&batt_b=B7223_AC&frame_b=semi&mass_b=150&hp_b=25&bopen=true&kv_b=7.44

I pull hills between 15 and 25 mph so there is not much difference in this range between the motors at the same power supplied.
Now you can ask why speed it up with volts then slow it down with more turns but the amps stay the same.

Here is a link to explain.
https://www.ebikes.ca/tools/simulator.html?motor=Leaf%205T&batt=B4823_AC&cont=C40&frame=semi&mass=150&hp=25&cont_b=C40&motor_b=Leaf%205T&batt_b=B7223_AC&frame_b=semi&mass_b=150&hp_b=25&bopen=true&kv_b=7.44

 

[John in CR]

My trike has a 7t at 72v the torque gained over the 5t is 20nm, for the same amps, then it drops down to match 5t at 6 mph. No free lunch the 7T motor starts losing power and torque at 28 mph which is the speed limit and I have my speed limited to it.

The 7t is a good match for the way I ride with the setup.

the 5t leafmotor has the best copper fill so it should be the most efficient.

Link to my setup 7t vs 5t
https://www.ebikes.ca/tools/simulator.html?motor=Leaf%205T&batt=B7223_AC&cont=C40&frame=semi&mass=150&hp=25&cont_b=C40&motor_b=Leaf%205T&batt_b=B7223_AC&frame_b=semi&mass_b=150&hp_b=25&bopen=true&kv_b=7.44

I pull hills between 15 and 25 mph so there is not much difference in this range between the motors at the same power supplied.
Now you can ask why speed it up with volts then slow it down with more turns but the amps stay the same.

Here is a link to explain.
https://www.ebikes.ca/tools/simulator.html?motor=Leaf%205T&batt=B4823_AC&cont=C40&frame=semi&mass=150&hp=25&cont_b=C40&motor_b=Leaf%205T&batt_b=B7223_AC&frame_b=semi&mass_b=150&hp_b=25&bopen=true&kv_b=7.44

Whichever motor has the highest copper fill is always the better motor as long as it can reach the speed you want with an 80V or less nominal battery. Once you get above 22s then controller selection and reliability is hard to find without spending a bundle. Then simply use a controller that can put out the slightly higher current you need. In your case the 5 turn matched with a 51V battery and a controller with a bit more oomph for exactly the same performance and a cooler motor.

To me riding an ebike that is used at full throttle all the time makes no sense. Would you ever purchase a car with such low performance? Why not be able to do the speed limit up hills or into headwinds? If you still want to adhere to exact limits for ebike speeds that is simple with the right electronics.

 

[Balmorhea]

To me riding an ebike that is used at full throttle all the time makes no sense. Would you ever purchase a car with such low performance? Why not be able to do the speed limit up hills or into headwinds?

Cruising at full throttle at the desired cruising speed (for electric bicycles with 250-1500W) means cruising in the most efficient, coolest running part of the power curve.

It also means having the most torque available to climb, or jump off the line, for any given controller. Higher top speed comes with lower low-end torque.

My primary e-bike has 48V x 35A of power available, but tops out between 18 and 22 mph depending on state of charge. That means it cruises extremely efficiently, but it also picks up power and torque immediately when loaded with an uphill grade or a headwind. It climbs the steepest grades I regularly encounter at about 15 mph and 1600-1800 watts, while barely getting warm. I wouldn't swap for a motor that tops out at a higher speed but climbs worse. What would be the point? It's a bicycle, not a motorcycle.

 

[John in CR]

To me riding an ebike that is used at full throttle all the time makes no sense. Would you ever purchase a car with such low performance? Why not be able to do the speed limit up hills or into headwinds?

Cruising at full throttle at the desired cruising speed (for electric bicycles with 250-1500W) means cruising in the most efficient, coolest running part of the power curve.

It also means having the most torque available to climb, or jump off the line, for any given controller. Higher top speed comes with lower low-end torque.

Those statements are not necessarily true, but for every situation they are true I can make the same happen at 80% throttle using the same motor as well as with a differently wound version of the same motor. The problem is that you continue to insist on essentially the same thing using different wording.

My primary e-bike has 48V x 35A of power available, but tops out between 18 and 22 mph depending on state of charge. That means it cruises extremely efficiently, but it also picks up power and torque immediately when loaded with an uphill grade or a headwind. It climbs the steepest grades I regularly encounter at about 15 mph and 1600-1800 watts, while barely getting warm. I wouldn't swap for a motor that tops out at a higher speed but climbs worse. What would be the point? It's a bicycle, not a motorcycle.

You conveniently left out that you slow down for every puff of wind or slightest incline, not to mention being screwed when you're stuck behind a dump truck doing 12mph up that hill.

FYI, since you commonly talk about torque and power like they're 2 separate things when power = torque X rpm. A given load whether it's overcoming gravity up a hill, or increase in wind load, or extra rolling resistance from more weight carried requires the same power for a given speed, and (assuming same copper fill) any variation of a motor can achieve the same results. In addition, our controllers are so good at feeding our motors that differences in throttle position to achieve the same rpm makes negligible difference.

If it wasn't for the extra rolling resistance of my chosen tires, my primary ebikes would cruise at your speeds more efficiently on the flats and definitely climb and accelerate much better, yet they have 3-5 times higher top speed. That's because the design is more efficient and has nothing to do with Kv.

 

[Balmorhea]

You can do things your way because you aren't using 250 to 1500W. You're using a lot more, which is a lot heavier, a lot more expensive, a lot riskier, and for most of us comes with a lot more administrative overhead.

We are talking about a 1500W motor that's available in any winding at no extra charge, and I'm talking about how to get the best out of that motor for any given riding situation. That doesn't include powering it at 10X its rating, nor using nonstandard and therefore expensive controllers, batteries, and chargers. If you assume the same power, then when you turn up the rpm/volt you turn down the torque, and the result is a weaker bike in every regard except top speed.

Setting up an electric vehicle to cruise at only the speed you need, and not more than that, is key to getting optimum performance at all lower speeds, plus optimum efficiency at cruise, with a minimum outlay in equipment and battery. It's approaching the problem like a cyclist and not a feckless motorist.

 

[ZeroEm]

I like this topic and have struggled with it. It does make it hard for nubies and john61ct to figure out what is right. It will all depend on what makes that person happy. Need to build your first E-bike and you will find out.

John in CR » Aug 22 2020 7:10am

Balmorhea wrote: ↑Aug 22 2020 12:13am

John in CR wrote: ↑Aug 21 2020 11:22pm
To me riding an ebike that is used at full throttle all the time makes no sense. Would you ever purchase a car with such low performance? Why not be able to do the speed limit up hills or into headwinds?

Cruising at full throttle at the desired cruising speed (for electric bicycles with 250-1500W) means cruising in the most efficient, coolest running part of the power curve.

It also means having the most torque available to climb, or jump off the line, for any given controller. Higher top speed comes with lower low-end torque.

Those statements are not necessarily true, but for every situation they are true I can make the same happen at 80% throttle using the same motor as well as with a differently wound version of the same motor. The problem is that you continue to insist on essentially the same thing using different wording.

Balmorhea wrote: ↑Aug 22 2020 12:13am
My primary e-bike has 48V x 35A of power available, but tops out between 18 and 22 mph depending on state of charge. That means it cruises extremely efficiently, but it also picks up power and torque immediately when loaded with an uphill grade or a headwind. It climbs the steepest grades I regularly encounter at about 15 mph and 1600-1800 watts, while barely getting warm. I wouldn't swap for a motor that tops out at a higher speed but climbs worse. What would be the point? It's a bicycle, not a motorcycle.

You conveniently left out that you slow down for every puff of wind or slightest incline, not to mention being screwed when you're stuck behind a dump truck doing 12mph up that hill.

FYI, since you commonly talk about torque and power like they're 2 separate things when power = torque X rpm. A given load whether it's overcoming gravity up a hill, or increase in wind load, or extra rolling resistance from more weight carried requires the same power for a given speed, and (assuming same copper fill) any variation of a motor can achieve the same results. In addition, our controllers are so good at feeding our motors that differences in throttle position to achieve the same rpm makes negligible difference.

If it wasn't for the extra rolling resistance of my chosen tires, my primary ebikes would cruise at your speeds more efficiently on the flats and definitely climb and accelerate much better, yet they have 3-5 times higher top speed. That's because the design is more efficient and has nothing to do with Kv.

I agree with both of you, Balmorhea is right and it would be the most efficient because we don't have self control. The setup would force you to be efficient with out thinking about it. When a person does not plan on peddling and talks of loads and hills then John in CR does it daily. hills and efficient should not be put to close together.

Efficiently is my game but moving closer to the teachings of John in CR. The reason torque is great for taking off but does not carry you up a hill motor power does. You want to pull the hills in your power range. Running at the top of the motors range is efficient but the motor can not respond to any load until it slows down. Your cruising speed should be past where your torque curve passes your power curve but not to close to the end.

 

[Balmorhea]

When a person does not plan on peddling

This motor is for a bicycle. Of course you pedal, unless your objective is to ride an extremely weak and flimsy motorcycle. But I’m not including pedal power in my comparisons.

The reason torque is great for taking off but does not carry you up a hill motor power does. You want to pull the hills in your power range. Running at the top of the motors range is efficient but the motor can not respond to any load until it slows down. Your cruising speed should be past where your torque curve passes your power curve but not to close to the end.

Bicycles slow down on hills. So do trucks and trains. It’s corollary to having the right amount of power for the job, and not excessive power that you have to pay extra for, and tote around all the time. It should be self-evident that you can climb much steeper hills with 1500W at 10mph, than with 1500W at 20mph, and that’s what a slow wind does for you (without resorting to weird expensive controllers and chargers, and DIY batteries). It’s relevant to what john61ct was asking about.

 

[John in CR]

When a person does not plan on peddling

This motor is for a bicycle. Of course you pedal, unless your objective is to ride an extremely weak and flimsy motorcycle. But I’m not including pedal power in my comparisons.

The reason torque is great for taking off but does not carry you up a hill motor power does. You want to pull the hills in your power range. Running at the top of the motors range is efficient but the motor can not respond to any load until it slows down. Your cruising speed should be past where your torque curve passes your power curve but not to close to the end.

Bicycles slow down on hills. So do trucks and trains. It’s corollary to having the right amount of power for the job, and not excessive power that you have to pay extra for, and tote around all the time. It should be self-evident that you can climb much steeper hills with 1500W at 10mph, than with 1500W at 20mph, and that’s what a slow wind does for you (without resorting to weird expensive controllers and chargers, and DIY batteries). It’s relevant to what john61ct was asking about.

No, no, and no for the umpteenth time. Winding in and of itself doesn't do anything for you unless you're already tied to a specific battery and/or controller. SLOW WIND MOTORS ABSOLUTELY DO NOT CLIMB HILLS ANY MORE EFFICIENTLY THAN THE FASTER WIND VERSION OF THE SAME MOTOR. If you're using the ebikes.ca simulator to prove otherwise, then your input parameters make a faulty comparison. It doesn't require custom batteries or big expensive controllers to match your performance with a faster wind version of whatever motor you use. In addition, the controller losses for the same power at partial throttle vs full throttle are small enough to ignore, so a faster ebike can be tuned to climb at the same speed just as efficiently. It goes without saying that greater performance increases consumption.

I'm not saying that everyone needs the kind of systems I use. I take mine to the extreme to promote the cause by showing what is possible and out accelerating almost everything else on the road is my addiction. If someone wants to build a 20mph bike, there's nothing wrong with that, and if they know with certainty they won't ever want more performance, then it really doesn't matter what motor they get, though I'd still steer them away from a slow wind motor, so they can run 24V or 36V instead of 48V. I do always recommend some headroom in terms of speed for the convenience and safety reasons previously mentioned. The desire for greater performance after the initial build is pretty typical, and a faster wind motor makes that path easier and more affordable. If you followed my typical advise up front and invested in a more flexible controller than the bare minimum to do the job initially, then all it takes is an increase in voltage to another common one.

When you're talking about direct drive hubbies I do always recommend the smallest size wheel you can live with, because unlike winding versions a smaller wheel does result in greater performance, better hill climbing, and greater efficiency.

If someone really does prize minimum consumption above all else at a given speed, then they should be building some kind of better aerodynamic form than a traditional upright ebike.

FWIW, I'm very frugal and build my own ebikes, so my first 100mph+ ebike cost only a little more than $1,000 , and the salvage batteries I use cost on a per watt-hour basis only a fraction of what any packs you can purchase. Plus they are superior on a cycle life and safety basis. Also, my ebikes are stronger and safer than common motorcycles. I'm lucky that cyclists didn't get to write the law here unlike the ridiculous restrictions they helped craft in many countries, so my DIY ebikes are 100% street legal. Laws so common elsewhere, would make affordable ebikes all but useless in mountainous terrain with the loads I need to haul, as well as more dangerous on our narrow mountain roads.

 

[john61ct]

You're using a lot more, which is a lot heavier, a lot more expensive, a lot riskier, and for most of us comes with a lot more administrative overhead.

We are talking about a 1500W motor that's available in any winding at no extra charge, and I'm talking about how to get the best out of that motor for any given riding situation. That doesn't include powering it at 10X its rating, nor using nonstandard and therefore expensive controllers, batteries, and chargers. If you assume the same power, then when you turn up the rpm/volt you turn down the torque, and the result is a weaker bike in every regard except top speed.

For me I am happy to spend more on a controller that will safely get more torque from a given motor, and especially on a FOC version to get precise torque control and better efficiency. Especially if I end up needing to coordinate 2WD.

Weight is not a huge concern for me, especially if it buys greater reliability.

Note not increasing my top speed, if that is a side effect, fine but not a goal for me.

I am happy to spend more on the packs, in fact resigned to that, need to in order to get reliability, better longevity and range anyway.

So I definitely do not "assume the same power", nor is going from say 48V to 60V or even 72V an issue, for me.

I am still uncertain about Kv / winding, in the above context, will that factor make a difference to my use case or not?

To me this report seems to imply yes it is relevant

My trike has a 7t at 72v the torque gained over the 5t is 20nm, for the same amps, then it drops down to match 5t at 6 mph. No free lunch the 7T motor starts losing power and torque at 28 mph which is the speed limit and I have my speed limited to it.

The 7t is a good match for the way I ride with the setup.

the 5t leafmotor has the best copper fill so it should be the most efficient.

I pull hills between 15 and 25 mph so there is not much difference in this range between the motors at the same power supplied.
Now you can ask why speed it up with volts then slow it down with more turns but the amps stay the same.

Is 7T means "7 turns" right?

a "slower winding" than 5T right?

lower Kv, less speed per volt, and also more torque per amp

Have I got those relationships right?

Someone, anyone, please confirm.

How can you find out, for a given motor, which winding has "the better copper fill"? Does that just mean **more** copper?

 

[Balmorhea]

Is 7T means "7 turns" right?

a "slower winding" than 5T right?

lower Kv, less speed per volt, and also more torque per amp

Have I got those relationships right?

Every one of your suppositions above is correct.

How can you find out, for a given motor, which winding has "the better copper fill"? Does that just mean **more** copper?

Copper fill is just the cross-sectional area of conductor per slot in the stator. More = better.

The Leaf 1500W motor? From information I’ve gleaned from sales@leafbike.com, the slots in the stator can fit 66 strands of the wire they use. So 6Tx11 or 11Tx6 have maximum fill. 5Tx13 is close. 4Tx16 and 8Tx8 are next. Etc. and so forth. 7Tx9 and 9Tx7 have the lowest fill of the windings that make sense for most of us, but the difference isn’t huge— It’s 63/66.

 

[ZeroEm]

In the beginning the 7T was to be laced into a 29" wheel. My project changed now it's in a 26". What about the smaller wheels? do you plan on peddling. The whole idea of the leafmotor it's hard to beat for the power and efficiently and still have a 7 speed in a standard drop out. I can only help the trike at 20 mph and lower with my 26" wheel and 50T chain ring. No, I can not peddle at 80-120 cadence. That is why larger wheels are needed. I say if you want a 20" rear wheel then get a large QS motor and put your single sprocket on it to make it look like a bike and have fun.

 

[John in CR]

The Leaf 1500W motor? From information I’ve gleaned from sales@leafbike.com, the slots in the stator can fit 66 strands of the wire they use. So 6Tx11 or 11Tx6 have maximum fill. 5Tx13 is close. 4Tx16 and 8Tx8 are next. Etc. and so forth. 7Tx9 and 9Tx7 have the lowest fill of the windings that make sense for most of us, but the difference isn’t huge— It’s 63/66.

Really??? The same guy going on and on about efficiency, is pushing the version of the motor with 4.5% less copper. Copper losses are the lion's share of motor losses and increase by the square of current, so they go up by torque squared.

 

[John in CR]

In the beginning the 7T was to be laced into a 29" wheel. My project changed now it's in a 26". What about the smaller wheels? do you plan on peddling. The whole idea of the leafmotor it's hard to beat for the power and efficiently and still have a 7 speed in a standard drop out. I can only help the trike at 20 mph and lower with my 26" wheel and 50T chain ring. No, I can not peddle at 80-120 cadence. That is why larger wheels are needed. I say if you want a 20" rear wheel then get a large QS motor and put your single sprocket on it to make it look like a bike and have fun.

It sounds like you need an extra large chain ring, or one of those Schlumpf Speed Drives. I don't understand...why do you think a big QS motor needs a smaller wheel more than your little Leaf motor. The Leaf certainly needs a small wheel more, especially the 7t version which makes the most heat for a given amount of torque, so it's the easiest to burn up.

 

[Balmorhea]

The Leaf 1500W motor? From information I’ve gleaned from sales@leafbike.com, the slots in the stator can fit 66 strands of the wire they use. So 6Tx11 or 11Tx6 have maximum fill. 5Tx13 is close. 4Tx16 and 8Tx8 are next. Etc. and so forth. 7Tx9 and 9Tx7 have the lowest fill of the windings that make sense for most of us, but the difference isn’t huge— It’s 63/66.

Really??? The same guy going on and on about efficiency, is pushing the version of the motor with 4.5% less copper. Copper losses are the lion's share of motor losses and increase by the square of current, so they go up by torque squared.

I wasn’t recommending any particular winding, because that’s specific to the application. What I was saying is that the difference between best and worst case in applicable windings is less than 5%. But in retrospect, 10Tx6 might otherwise work for some RPM requirements, and has much worse fill at 91% of optimum. A different wire gauge that uses more of the slot in that winding would be a good idea, but isn’t likely for a low cost operation like Leaf.

Their sales reps are proactive about discouraging use of turn counts with poor fill, which I think is commendable.

 

[Balmorhea]

No, I can not peddle at 80-120 cadence.

Can’t pedal at 80 rpm? That’s very unusual.

 

[ZeroEm]

by Balmorhea » Aug 23 2020 4:44pm

ZeroEm wrote: ↑Aug 23 2020 5:45am
No, I can not peddle at 80-120 cadence.

Can’t pedal at 80 rpm? That’s very unusual.

It causes me back pain if I keep it up, can live with 70 rpm. So have you peddled a trike at 100 rpm 25 mph sorta of wild. Would like to get to 70 rpm @ 28 mph/46 kph. I do rides up to 4 hrs then i'm ready to get off.

 

[John in CR]

The Leaf 1500W motor? From information I’ve gleaned from sales@leafbike.com, the slots in the stator can fit 66 strands of the wire they use. So 6Tx11 or 11Tx6 have maximum fill. 5Tx13 is close. 4Tx16 and 8Tx8 are next. Etc. and so forth. 7Tx9 and 9Tx7 have the lowest fill of the windings that make sense for most of us, but the difference isn’t huge— It’s 63/66.

Really??? The same guy going on and on about efficiency, is pushing the version of the motor with 4.5% less copper. Copper losses are the lion's share of motor losses and increase by the square of current, so they go up by torque squared.

I wasn’t recommending any particular winding, because that’s specific to the application. What I was saying is that the difference between best and worst case in applicable windings is less than 5%. But in retrospect, 10Tx6 might otherwise work for some RPM requirements, and has much worse fill at 91% of optimum. A different wire gauge that uses more of the slot in that winding would be a good idea, but isn’t likely for a low cost operation like Leaf.

Their sales reps are proactive about discouraging use of turn counts with poor fill, which I think is commendable.

What would be commendable is if they would only produce 1 or maybe 2 versions of winding with optimum fill on both, say a 6t and a 3t with the 3t having twice as thick phase wires. That would cover all performance requirements. Then recommend right voltage to get the appropriate speed for different wheel sizes. The "speed wind/torque wind" stuff rampant in the industry represents either fraud or a lack of knowledge, neither of which are commendable in the least. The fact that they make a silly 11t and don't make a 3t, which should be the only version, demonstrates real lack of knowledge.

 

[Balmorhea]

What would be commendable is if they would only produce 1 or maybe 2 versions of winding with optimum fill on both, say a 6t and a 3t with the 3t having twice as thick phase wires. That would cover all performance requirements. Then recommend right voltage to get the appropriate speed for different wheel sizes. The "speed wind/torque wind" stuff rampant in the industry represents either fraud or a lack of knowledge, neither of which are commendable in the least.

Phase wire size is limited by mechanical factors that don’t change to suit your fanciful imagination.

It’s much, much easier to simply request (at no extra cost) the motor winding that matches an inexpensive, readily available controller, commodity battery pack, and easy to work with wire gauges, to the road speed you want for your project. Using an uncommon voltage or unusually high current has practical costs and tradeoffs, whereas the winding is entirely elective and free of charge in this case.

One of my projects used a too-fast motor that I received in trade for some custom metalwork. I ran it at 24V, to limit the bicycle’s speed to less than 25mph. But I had to spend more on the controller after a protracted search, and use two battery packs in parallel, to do what would have been cheaper, lighter, simpler, easier to build, and easier to find, if the motor had been wound to work right with 36 or 48 volts.

The implications of matching john61ct’s low-speed performance requirements with either a 6T a 3T motor are absurd compared to using say an 11T motor. With a 3T, you’d spend a fortune, and probably burn the phase wires entering the motor, trying to do what the 11T would do with no problem and with a plug-and-play Leaf Bike supplied controller.