Slowest wind direct drive hub motor(s) available?

[ebike4healthandfitness]

What is the slowest wind direct drive hub motor available?

 

[qwerkus]

I guess any 25km/h 48V DD hub for 29" will have a super slow wind.

 

[markz]

MXUS has a 6 Turn motor you can view on the Motor Simulator, there is probably even a 7 or 8 turn motor.
9C states 7T
MAC 10T

ES search function doesnt work well with number or 2 letters.

 

[MadRhino]

When you buy direct from the manufacturers, you can order the winding that you want. If it is very unusual, you will have to wait but the cost will be the same.

 

[ZeroEm]

I run a 7T but know they have higher turns than that and DogmanDan wrote of him having a 10T.

 

[markz]

When you buy direct from the manufacturers, you can order the winding that you want. If it is very unusual, you will have to wait but the cost will be the same.

That to

Wonder how large you can go, 14T or 20T - be some awfully thin and long magnet wire. Problems with trying to control 1T.
I wonder how they calculate the wire size for fill wouldnt be to hard.

 

[Balmorhea]

What is the slowest wind direct drive hub motor available?

Leaf Bike will make you whatever winding you want for their 1000W and 1500W direct drive hubs, no extra charge. If you tell them what wheel size and speed you want, or how many RPM you want, they'll choose the best winding for the job. For the 1500W motor, 11 turn gives a good copper fill and should give an unloaded speed of 215-220 RPM at 48V. 13 turn also has good fill and and should have a free RPM of about 185 at 48V.

If this is about using high voltage to make low power, you're barking up the wrong tree. Use the voltage range that gets you the best prices and variety in controllers and batteries. That's 36, 48, or 52 volts. The only advantage to using more than 52 volts is that makes it easy to get higher power and speed from motors that were designed for lower voltage. If you're not hot rodding, there's nothing to be gained there.

 

[ebike4healthandfitness]

Use the voltage range that gets you the best prices and variety in controllers and batteries. That's 36, 48, or 52 volts.

I'm not always seeing 72v controllers being so much more expensive. (e.g. This little sine wave one from Luna is only $49.99 and works with any brushless motor ---> https://lunacycle.com/replacement-48-72v-cyclone-ebike-controller/)

Also even if I was using a 52v (14S) battery wouldn't it be better to buy a 72v/48v controller (rather than a 48v/36v controller) for the extra durability? (I've read people saying that running 52v battery on 48v controller can stress the controller and reduce its lifespan.)

The only advantage to using more than 52 volts is that makes it easy to get higher power and speed from motors that were designed for lower voltage. If you're not hot rodding, there's nothing to be gained there.

If the motor wind is slow enough and/or wheel size is small enough the extra speed will be very necessary just to get 20 mph (or 28 mph with pedaling) top speed.

20 mph (or 28 mph with pedaling) top speed is not hot rodding.

 

[markz]

You can use a 36V controller to 60V which is 14S fully charged, its what the capacitors are rated for, but some might have 50V caps inside in which case you'd blow the controller. 72V and 60V controllers would use 100V capacitors inside the controller.

I have used 36V 40A controller with my new 14S battery and it works fine, lots of extra power to get up the hills. I actually have 2 batteries on the same bicycle, a 36V and the 52V, I use both on same ride same controller. 36V is weak for this one hill because I have to help by pedaling, while the 52V is strong and no pedaling. I ordered a 5T in Leaf 1500W, I have never confirmed but thats what I told them I wanted.

 

[Balmorhea]

20 mph (or 28 mph with pedaling) top speed is not hot rodding.

Right. That's why you don't get any advantage by using high voltage.

I'm quick to advocate for using the right winding for the job. In most cases, that's a slower winding than the industry provides as a default. But since you're only looking for 750W peak and 20mph without pedaling, you can easily do that with a default fast-ish winding and a 36V/25A controller. That's a dirt common setup all over the world. So is 48V/20A. 72V/13À? Not so much.

So yeah-- if your goal is to use 72V to do something that millions of people are already doing with 36V, it is possible to do that. But you'll be using a weird battery (or two batteries) and a weird controller (or a needlessly powerful but restricted controller) to do it, and not getting anything that you wouldn't get from the far more common and cheaper setup. And you will have crossed over from generally-safe voltage to generally-unsafe voltage.

 

[ebike4healthandfitness]

@Balmorhea,

The advantage of the high voltage (with the slow winding) is torque and efficiency.

Getting 20 mph (without pedaling) could be done with low voltage and a faster wind motor......but it wouldn't climb as well.

 

[ZeroEm]

20 mph is not a hard speed to get to, my mother's set up is a little Bafang geared motor 48V and 20A controller (have it limited to 13A) it's gets to 20 mph and pulls hills good on her trike. Going above 20 you start pushing wind and the more wind you push the more power you need.

Did not say she pulls hills at 20 more like 10-15 mph, My trike pulls the hills at 25 mph. She is running 700w max, I can run 2600w pushing the wind. If I keep the speed around 15 mph it only takes me 1100-1500w to pull hills.

 

[Balmorhea]

@Balmorhea,

The advantage of the high voltage (with the slow winding) is torque and efficiency.

Getting 20 mph (without pedaling) could be done with low voltage and a faster wind motor......but it wouldn't climb as well.

It's just not true. Watts are watts. 750W at 24V/40A and 200 RPM doesn't climb any better than 750W at 48V/20A and 200 RPM.

High turn count motors have to fit more length of wire into the same stator slots. And that wire has to be thinner. So I^2R evens out. There's no efficiency to be had in higher voltage if you go the same speed in the same conditions. Same torque, same power, same speed, same efficiency; you just trade volts against amps by juggling voltage and motor winding.

However, high turn count, same voltage means you go slower, which becomes much more efficient with small reductions in speed.

 

[MadRhino]

Of course 20 mph is easy to do, and ride. I mean, on the street you don’t even need a good bike at such speed. I’d say it is above 35 mph that things are getting more complicated, because then all the factors that are making a good ride, are becoming important.

 

[ebike4healthandfitness]

@Balmorhea,

The advantage of the high voltage (with the slow winding) is torque and efficiency.

Getting 20 mph (without pedaling) could be done with low voltage and a faster wind motor......but it wouldn't climb as well.

It's just not true. Watts are watts. 750W at 24V/40A and 200 RPM doesn't climb any better than 750W at 48V/20A and 200 RPM.

Here is a 24v system (using the faster wind Clyte H3540 laced to a 29" wheel) vs. a 48v system (using a slower wind Clyte H3525 laced to a 20" wheel) on a 7% grade:

https://ebikes.ca/tools/simulator.html?motor=M3540&cont=PR&batt=B2412SLA&wheel=29i&grade=7&hp=0

https://ebikes.ca/tools/simulator.html?motor=M3525&cont=PR&batt=B4816_GA&wheel=20i&grade=7&hp=0

Both systems have a top speed of around 19 mph (48v= 30.5 kph vs. 24v= 30.3 kph) when on flat ground (see links below), but when it comes to a 7% grade (as shown by the two links above) the 48v climbs faster (26.2 kph vs. 22.6 kph) while using less energy per km (32.3 wh/km vs. 36.3 wh/km).

https://ebikes.ca/tools/simulator.html?motor=M3540&cont=PR&batt=B2412SLA&wheel=29i&grade=0&hp=0

https://ebikes.ca/tools/simulator.html?motor=M3525&cont=PR&batt=B4816_GA&wheel=20i&grade=0&hp=0

 

[Balmorhea]

Here is a 24v system (using the faster wind Clyte H3540 laced to a 29" wheel) vs. a 48v system (using a slower wind Clyte H3525 laced to a 20" wheel) on a 7% grade

The winding isn't proportional to the voltage, isn't proportional to the free speed. Changing the wheel diameter renders the comparison useless. Smaller wheels are better for hub motors, but worse for humans riding them.

If you want to get the very best from a hub motor, then use a small wheel-- but it will beat you up. And that's a totally different factor than voltage. Same wheel, same power, same unloaded speed, you'll get the same efficiency with 72, 48, 36V.

 

[ebike4healthandfitness]

Here is a 24v system (using the faster wind Clyte H3540 laced to a 29" wheel) vs. a 48v system (using a slower wind Clyte H3525 laced to a 20" wheel) on a 7% grade

The winding isn't proportional to the voltage, isn't proportional to the free speed. Changing the wheel diameter renders the comparison useless. Smaller wheels are better for hub motors, but worse for humans riding them.

If you want to get the very best from a hub motor, then use a small wheel-- but it will beat you up. And that's a totally different factor than voltage. Same wheel, same power, same unloaded speed, you'll get the same efficiency with 72, 48, 36V.

Here are the results for 24v with 20" wheel:

https://ebikes.ca/tools/simulator.html?motor=M3548&cont=PR&batt=B2412SLA&wheel=20i&grade=7&hp=0

https://ebikes.ca/tools/simulator.html?motor=M3548&cont=PR&batt=B2412SLA&wheel=20i&grade=0&hp=0

Combining the data in the above links with the results reported in my previous post here is what we get:

24v system using Clyte H3540 and 29" wheel:

Top speed on flat ground: 30.3 kph
Climbing speed up 7% grade: 22.6 kph
Energy consumption during climb 36.3 wh/km

24v system using Clyte H3548 and 20" wheel:

Top speed on flat ground: 27.8 kph
Climbing speed up 7% grade: 22.6 kph
Energy consumption during climb 32.6 wh/km

48v system using Clyte H3525 and 20" wheel:

Top speed on flat ground: 30.5 kph
Climbing speed up 7% grade: 26.2 kph
Energy consumption during climb 32.3 wh/km

Climbing speed for 24v is just as slow as it was before, but the top speed also drops 2.8 kph. Energy consumption during the climb does improve but is still worse than 48v.

 

[markz]

Just buy a motor that suits your needs for the speeds you want and buy corresponding controller and battery.

If you already have a controller or battery then match the motor.

 

[dogman dan]

There is one reason to pick a slow wind motor. Because you want to go slower all the time, but still have decent power compared to running lower voltage and lower wattage.

Slowest motors I have are some 9 continent DD rear motors in 12t. I used to run them to ride trails, and I'd fry one every spring. Never toasted the windings, but I'd regularly cook off the halls every spring.

All winter, Id run 72v 40 amps lyens controller, till I killed a motor. Then I'd swap in the other one, and run 72v 20 amps all summer. I did this because at the time, I was still too weak and sick to pedal, any. Over the next year, usually in the winter, I'd put new halls in the fried motor and be ready for the swap again next spring.

Basically, running that size, 500w rated motor on 3000w was dumb as a bag of rocks. However, if it was only 50 degrees out there, I'd get through a 45 min ride without killing the motor. So this was not efficient in any way, because that size motor simply cannot handle 3000w for long without overheating, unless it was good and cold. First 80 degree day, I'd fry that thing again. At 3000w, I was wasting a lot of it into excess heat when I used full throttle.

So why did I do this? I needed a low speed wind because the steep trails and deep sand killed a 7 t motor even quicker. I just needed slow wind so I could go slow. NOT because it had more torque. But it was more efficient at 10 mph under outrageous load, than a 7 t wind.

AGAIN, you pick a slow motor to go slow. Not to gain efficiency going fast. To gain efficiency going very very slow under very very heavy load. A slow wind will never be a substitute for more copper. A slow motor lugging up the hill will actually refuse to pull on the controller as hard as a fast wind. This is why the real way to blast up a hill heavily loaded is a big ass motor, big ass high volt controller, and ideally a smaller wheel.

E-bikekit sells a 10 turn 500w rated dd motor. They call it the heavy duty motor. Perfect for delta trikes, and cargo bikes that are heavy.

FWIW now that I can pedal again, I just run a 48v 500w rated geared motor, and never overheat on the same trails I used to ride the DD motors on. Pedaling allows me to keep my speed up going up those same hills, and I go twice as far on the same watt hours. In other words, you want efficiency? Ride 15 mph and pedal hard as you can.

 

[Tommm]

Geared motors usually have a slower wind and weigh less too

 

[ebike4healthandfitness]

dogman dan,

There actually is a 72v 20amp controller?

 

[markz]

dogman dan,

There actually is a 72v 20amp controller?

Yes

72V 100A - That thing would be a beast, like the green giant literally - https://evfittinggreentime.aliexpress.com/store/group/30-36-mosfets-type/313864_259097442.html?spm=2114.12010615.pcShopHead_11248317.1_0_6

Bunch of 80A and 65A
Heck they even have dimensions for you to gaze and ponder at.
https://evfittinggreentime.aliexpress.com/store/group/24-mosfet-type/313864_259098441.html?spm=2114.12010615.pcShopHead_11248317.1_0_5

 

[dogman dan]

That controller I got from Lyens, at least 10 years ago. To make a typical cheap controller lower amps, just cut a shunt.

Often a 40 amps controller has three shunts, so cut one and you get about 26 amps. That should do. Or use a three speed switch on a controller.

But you were talking on the other thread about limiting speed to 28 mph. Thats easy too. You could put a DP Cycle Analyst on the controller and set your speed limit. Or amps limit. Then you don't need a low speed wind. And can remove that limit for a big mountain climb.

Any of that could work better for you than trying to find a slow motor. Get the slow motor only if you NEVER want to go faster, or have more power, and if you want it to climb better, put whatever motor you get into a 20" rim.

 

[goatman]

a phaserunner and then you can set watts or amps or any volt you want. i use it at 17s 3500 watts on a 3540 if i want or at 2500watts or change the lvc and put on a 13s battery or use at 17s and 2200 watts in my mxus xf40 in a 20 inch wheel on my trike with a topspeed of 75km/h down a hill or haul a trailer up a hill at 50km/h, my motors never been hot. my 3540 at 48v and a 20amp infinion was gutless, controller gets hot and dies not enough mosfets. if you overwork a phaserunner itll just go into thermal rollback, it doesnt blow up.

 

[dogman dan]

Not so likely to blow up a 12 or more fet cheap 40 amps controller, once you cut a shunt and lower the amps.

But they don't last forever, they are cheap controllers.

A better controller that lasts, and is programmable is of course a lot more adaptable in the future.

Just wanted to point out it can be done on the cheap, to get a 72v controller with lower amps.

On the other hand, few things work as great as good controller combined with a DP CA. Run any amps you want up to the controllers max. Very good for experimentation, since you can change settings while out riding.