Leafmotor project

General Discussion about electric bicycles.
Funkonabike   10 µW

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Leafmotor project

Post by Funkonabike » Sep 10 2020 5:36pm

hello everyone
First ebike project here, think I've finally settled on what I want to put together. I'm thinking a 52v 20ah triangle battery from em3ev paired with the leaf 1500w 700c is what im looking at. I'd also be upgrading to a 40 or 60 amp controller from luna. Pushing about 200lbs altogether.

Does anyone have a recommendation between a 4t and a 5t leaf motor? Read through neptronix's leaf adventure thread and im not sure definitively what to expect with either set up on the 700c wheel, and would rather not burn up a motor figuring it out.

Also, if anyone has any advice where to get the leafbike motor without paying 198$ for shipping to the US, that'd be awesome.

Thanks everyone!

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E-HP   1 MW

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Re: Leafmotor project

Post by E-HP » Sep 10 2020 7:56pm

Funkonabike wrote:
Sep 10 2020 5:36pm

Does anyone have a recommendation between a 4t and a 5t leaf motor? Read through neptronix's leaf adventure thread and im not sure definitively what to expect with either set up on the 700c wheel, and would rather not burn up a motor figuring it out.
A recommendation would be dependent on what you want to do with the bike, desired speed, terrain, etc. I'd go for the 5T, based on my own requirements.

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ZeroEm   100 kW

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Re: Leafmotor project

Post by ZeroEm » Sep 10 2020 8:28pm

Just my point of view, you are only looking at 3 mph difference between the two. 700 wheel and 52V the 5T would be better for the setup and could run a 40A controller. The 4T you would need a 60A controller. No matter what get the temperature sensor working they will put one in for you but may not match your setup but the wires will be run thru the axle.
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Funkonabike   10 µW

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Re: Leafmotor project

Post by Funkonabike » Sep 10 2020 8:42pm

Ah yes, I live in a fairly flat area with some hills but they're lower grade for longer periods typically, but nothing too crazy. Most of them are easily manually cycled up.

I figure the leaf motor can handle the hills at 1500 on the em3ev battery and it should also leave some room to crank it up later on.

Ideally looking for a 35 to 38ish cruising speed max or so, much faster is kind of scary for any sustained periods in most conditions. I'd guess the 5t with a 40a is suitable? I could sacrifice the near 40 mph for the better low end climbing when needed.


markz   100 GW

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Re: Leafmotor project

Post by markz » Sep 25 2020 3:29pm

I'd go with a higher turn count for a 700C, 6,7,8T.

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E-HP   1 MW

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Re: Leafmotor project

Post by E-HP » Sep 25 2020 3:55pm

markz wrote:
Sep 25 2020 3:29pm
I'd go with a higher turn count for a 700C, 6,7,8T.
I would too, but even 5T won't meet the 35-38 mph criteria.

AHicks   1 kW

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Re: Leafmotor project

Post by AHicks » Sep 25 2020 7:14pm

I think when you see your available range at speeds over about 25mph, there will be a reality check, and a new much lower expectation will surface....

My vote would be for more turns as that's going to equal more torque, which will be really nice to have when not out on a level road. City driving, stopping and starting constantly, will show the relatively gutless performance available from a direct drive hub at speeds under about 15mph. You're going to want all the torque you can get there.

The guys getting good low speed performance from direct drive hubs are all using way more than 52v, with huge batteries capable of supplying super high amps.

markz   100 GW

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Re: Leafmotor project

Post by markz » Sep 26 2020 12:33am

AHicks wrote:
Sep 25 2020 7:14pm
I think when you see your available range at speeds over about 25mph, there will be a reality check, and a new much lower expectation will surface....

My vote would be for more turns as that's going to equal more torque, which will be really nice to have when not out on a level road. City driving, stopping and starting constantly, will show the relatively gutless performance available from a direct drive hub at speeds under about 15mph. You're going to want all the torque you can get there.

The guys getting good low speed performance from direct drive hubs are all using way more than 52v, with huge batteries capable of supplying super high amps.
Hmmmm more torque myth....... AGAIN
Two same motors of different wind counts do not have a) more torque or b) more speed, they both have the exact same torque and speed. Playing around with tire diameter, controller voltage and controller amps, gauge and length of battery cables and phase wires you can make a 3T the same torque and speed as a 5T. Having a 3T laced into a 29"/700C tire is going to heat things up, but getting it into a 20" wheel will cool the same setup. You'd need more voltage for more speed in the 20" to gain lost speed.
viewtopic.php?f=2&t=64907&hilit=myth&start=625

You can play around with two motors in the same graph here
https://www.ebikes.ca/tools/simulator.html

Balmorhea   100 kW

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Re: Leafmotor project

Post by Balmorhea » Sep 26 2020 1:51am

markz wrote:
Sep 26 2020 12:33am
Two same motors of different wind counts do not have a) more torque or b) more speed, they both have the exact same torque and speed.
More torque PER AMP is not a myth; it's the other side of lower rpm/volt.

They're only equal if
1) you drive them both to saturation, and
2) you have controllers and batteries able to do that.

We don't. We have normal controllers and batteries, the kind that cost what we're willing to pay, that allow us to use our bikes without risk of pushing them to the breaking point.

Yes, most of our controllers will send about 2X as much phase current as battery current. But remember, torque per amp. The slower wind makes more torque when the controller is doing all it can, if it's a regular controller like most of us use.

People who overdrive their stuff so hard that they have to use active cooling to keep it from burning down, have other limits that come into play first.
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John in CR   100 GW

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Re: Leafmotor project

Post by John in CR » Sep 26 2020 9:20am

Balmorhea wrote:
Sep 26 2020 1:51am

...They're only equal if
1) you drive them both to saturation, and...
Wrong as usual. They are the same motor and are in no way the equivalent of changes in gearing. They simply require a different combination of voltage and current for the same result. I take my earlier statement back. You don't ride with a concrete helmet, but with a concrete filled helmet. As evidence, after being presented with the facts numerous times you continue to push the slow wind nonsense like it makes more torque without making more heat. You also refuse to accept that smaller wheels have an across the board advantage in efficiency and performance using the same motor. Then you argue that regen braking is only useful for a small portion of ebikers, and your latest argument is that riding at night is as safe or safer than riding in the day when it's a simple fact that you're much more likely to get killed if you ride at night.

The real problem with the OP's plan is that he wants a top speed of almost 40mph with a hubmotor in a 700C wheel. The wheel size is the flaw. While it may work with his relatively light load and gentle terrain, the motor will run hotter and his battery pack will have less range than running a smaller wheel no matter what turn count version of the motor he purchases.

Balmorhea   100 kW

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Re: Leafmotor project

Post by Balmorhea » Sep 26 2020 12:45pm

And yet, after all the hot air, a Leaf motor with a 48V battery, a 35A controller, and a slow winding will make more torque than a Leaf motor with a 48V battery, a 35A controller, and a fast winding. That's the other side of the equation that has rpm in it.

Maybe I should point out that the manufacturer's kit containing a Leaf 1500W motor also contains a 48V, 35A controller. Just in case you were expecting a 12V 150A controller that might work better with a fast winding.

In this case, the OP intends to use a different controller, but the same principles apply. His voltage is fixed at 52V and the max current is either 40 or 60A. Those factors are set, so the fast wind and slow wind won't perform equally. One will turn faster and the other will turn with more torque.

Full sized wheels don't have an advantage for the hub motor. They have multiple advantages for the rider. That's why they're full sized.
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AHicks   1 kW

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Re: Leafmotor project

Post by AHicks » Sep 26 2020 2:21pm

[/quote]
Hmmmm more torque myth....... AGAIN
Two same motors of different wind counts do not have a) more torque or b) more speed, they both have the exact same torque and speed. Playing around with tire diameter, controller voltage and controller amps, gauge and length of battery cables and phase wires you can make a 3T the same torque and speed as a 5T. Having a 3T laced into a 29"/700C tire is going to heat things up, but getting it into a 20" wheel will cool the same setup. You'd need more voltage for more speed in the 20" to gain lost speed.
viewtopic.php?f=2&t=64907&hilit=myth&start=625

You can play around with two motors in the same graph here
https://www.ebikes.ca/tools/simulator.html
[/quote]

Grin sells differently wound MAC motors - 8t through 12t. Suggest you have a look to see what they say about the different number of windings they offer. That may temper your thoughts a bit....

John in CR   100 GW

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Re: Leafmotor project

Post by John in CR » Sep 26 2020 8:12pm

AHicks wrote:
Sep 26 2020 2:21pm

Hmmmm more torque myth....... AGAIN
Two same motors of different wind counts do not have a) more torque or b) more speed, they both have the exact same torque and speed. Playing around with tire diameter, controller voltage and controller amps, gauge and length of battery cables and phase wires you can make a 3T the same torque and speed as a 5T. Having a 3T laced into a 29"/700C tire is going to heat things up, but getting it into a 20" wheel will cool the same setup. You'd need more voltage for more speed in the 20" to gain lost speed.
viewtopic.php?f=2&t=64907&hilit=myth&start=625

...Grin sells differently wound MAC motors - 8t through 12t. Suggest you have a look to see what they say about the different number of windings they offer. That may temper your thoughts a bit....
Don't pay any attention to Balmorhea, as he'll just invent conditions to avoid ever admitting being wrong, just like he tried with his last post here. Thanks for mentioning that Grin sells MAC motors...actually it looks like now it's only the GMAC in 2 different windings, a motor built to Grin's specs. After seeing pics of MAC motor guts I had long suspected they did their different wind count versions without regard to achieving equal copper fill. With the GMAC we can be assured that isn't the case.
Last edited by John in CR on Sep 28 2020 1:43am, edited 1 time in total.

Balmorhea   100 kW

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Re: Leafmotor project

Post by Balmorhea » Sep 27 2020 1:20am

The motor can be ordered with an inexpensive controller, which is spec'ed for the motor. It also comes with your choice of winding at no charge. Why would any sane, not obsessed person choose to go on an exotic controller and battery quest rather than just choose the right winding for the job (purpose and wheel diameter), at zero extra cost?
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John in CR   100 GW

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Re: Leafmotor project

Post by John in CR » Sep 28 2020 3:30am

Balmorhea wrote:
Sep 27 2020 1:20am
The motor can be ordered with an inexpensive controller, which is spec'ed for the motor. It also comes with your choice of winding at no charge. Why would any sane, not obsessed person choose to go on an exotic controller and battery quest rather than just choose the right winding for the job (purpose and wheel diameter), at zero extra cost?
Funkonabike seems perfectly sane and non-obsessed, and there is no such thing as "the right winding for the job (purpose and wheel diameter)", especially since he has neither a controller nor battery already. There's also no such thing as an "exotic controller".

The problem is that you'd rather people not know the cold hard facts regarding getting absolute reliability using hubmotors, since you make money on repairs that are no doubt far more expensive than setting up correctly from the start. Keep the customers ignorant of the truth so you can continue to sell pedal bikes for many thousands of dollars is your MO.

I on the other hand believe new ebikers should be well informed in order to make good purchase decisions. Heat is our electrical systems' limitation. The more heat the motor and controller make the more likely they are to fail and the less range we get out of our battery packs. While in low demand use (flat terrain, low speeds, no big loads to push), just about anything can be pretty reliable and useful. It's a simple fact that large wheels are a big compromise in terms of heat, one not discussed often enough to prevent a significant portion of forum members from burning up their motors. This is readily apparent using Ebikes.ca simulator, and bigger definitely is not better when it comes to wheel size mounted on hubmotors. Any direct drive hubmotor with any winding makes more heat in a larger wheel.

The OP wants a top cruising speed of almost 40mph and he's already talking about juicing up performance in the future, which is common once someone gets a taste of electrics. That makes a 700C wheel a serious mistake, especially when combined with controllers that don't have thermal cutback settings. It's baffling why people are still so insistent to apply the norms of pedal bikes when it comes to wheel size to hubmotored ebikes too, despite it being such a big compromise. It's not just hotrodders who burn up their hubbies. It's regular people just trying to get up a hill too, and the hill doesn't have to be that steep either. They just combined the wrong conditions with a wheel size that caused heat and less range from the start.

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Re: Leafmotor project

Post by Balmorhea » Sep 28 2020 10:54am

John in CR wrote:
Sep 28 2020 3:30am
It's not just hotrodders who burn up their hubbies. It's regular people just trying to get up a hill too, and the hill doesn't have to be that steep either. They just combined the wrong conditions with a wheel size that caused heat and less range from the start.
You mean folks who use too fast a winding for the amount of power they have available.
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John in CR   100 GW

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Re: Leafmotor project

Post by John in CR » Sep 28 2020 10:56am

Balmorhea wrote:
Sep 28 2020 10:54am
John in CR wrote:
Sep 28 2020 3:30am
It's not just hotrodders who burn up their hubbies. It's regular people just trying to get up a hill too, and the hill doesn't have to be that steep either. They just combined the wrong conditions with a wheel size that caused heat and less range from the start.
You mean folks who use too fast a winding for the amount of power they have available.
Wrong again.

Balmorhea   100 kW

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Re: Leafmotor project

Post by Balmorhea » Sep 28 2020 11:19am

John in CR wrote:
Sep 28 2020 10:56am
Balmorhea wrote:
Sep 28 2020 10:54am
John in CR wrote:
Sep 28 2020 3:30am
It's not just hotrodders who burn up their hubbies. It's regular people just trying to get up a hill too, and the hill doesn't have to be that steep either. They just combined the wrong conditions with a wheel size that caused heat and less range from the start.
You mean folks who use too fast a winding for the amount of power they have available.
Wrong again.
No, it's not. If you have enough gross power to go 20 mph, having a motor+controller that wants to turn at 40 is a mistake that makes your bike run weak and hot. And yet that's the sort of mistake you tell people to make all the time.
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donn   10 kW

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Re: Leafmotor project

Post by donn » Sep 28 2020 12:27pm

Just looking at the simulator, with a pair of 9C+ motors, 2705 vs 2707, with a 20A controller.
  • Torque is quite different at low RPM. 2505 tops out at 30nm up to 200rpm; 2507 tops out at 41nm up to 100rpm. Once the rpms are over 200, though, torque is roughly the same between the two.
  • Top speed is of course higher with the 2505 - so I pulled the 2505 throttle back to 74% to get the same 30mph speed. From that point of view, these two hubs are really quite similar - the 2507 is more efficient here, but it's 86.5% to 85%, nothing you'd notice.
  • Adding a 4% grade, the throttle issue goes away - the 20A controller is maxed out and they both run the same speed at 100% throttle. The 2507 is more efficient as we would expect - 82.2% vs 79.8% - a surprisingly small 2.4% difference. Final temperature 76° vs 77°.
  • As the grade goes up, the 2505 falls farther behind, but hanging in there up to 8%. Then it apparently folds, while the 2507 carries on up to 12%.
For me, the moral of the story appears to be that my motor, which is a direct drive like this with a high turn count, was a fine choice for me even though it's on a 26 inch wheel, because I get more oomph at low RPM, it's very slightly more efficient at normal speed and I don't care a bit about riding at or over 30mph on a bicycle - but if I swapped in the same motor with a lower turn count, I'd probably never know the difference, so if I'd wanted to ride real fast, that's what I'd want. Or certainly if I had a smaller diameter wheel.

Above numbers are with full recumbent, 26" wheel, 0 pedal power.

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Re: Leafmotor project

Post by Balmorhea » Sep 28 2020 1:18pm

Here's another example:
Screenshot_20200928-125225~2.png
Screenshot_20200928-125225~2.png (344.54 KiB) Viewed 303 times
The higher turn count winding has more power and better efficiency in the relevant speed range, and about 50% more initial torque. Plus you can cruise at full throttle at a speed that makes sense for a bicycle, and not dither around trying to average 56% throttle.

Same systems, both at full throttle:
Screenshot_20200928-130215~2.png
Screenshot_20200928-130215~2.png (325.41 KiB) Viewed 303 times
The fast wind doesn't do anything as well as the slow wind until you surpass 17mph.

Like most folks, I live in a city. Zero to 20mph is the range where my bike's performance matters. How it performs at higher speeds is unimportant, because I usually don't go at those speeds. Others have different speed objectives, but it's always beneficial to get the right kV for the job, rather than one that's faster.
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donn   10 kW

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Re: Leafmotor project

Post by donn » Sep 28 2020 3:49pm

Balmorhea wrote:
Sep 28 2020 1:18pm
Like most folks, I live in a city. Zero to 20mph is the range where my bike's performance matters. How it performs at higher speeds is unimportant, because I usually don't go at those speeds. Others have different speed objectives, but it's always beneficial to get the right kV for the job, rather than one that's faster.
Yeah, it's beneficial - a long as you don't get too "wound up" over a couple percentage points that aren't going to make the kind of difference that anyone would notice.

Thinking about the fast wind's modest performance at slow RPM, I expect that's usually a factor in starts, not so much my ridiculous 12% grade. But it isn't clear to me that it's really such a bad thing - actually it might save wear and tear on the dropouts, which I know is something you care about a lot.

Balmorhea   100 kW

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Re: Leafmotor project

Post by Balmorhea » Sep 28 2020 4:43pm

donn wrote:
Sep 28 2020 3:49pm
Balmorhea wrote:
Sep 28 2020 1:18pm
Others have different speed objectives, but it's always beneficial to get the right kV for the job, rather than one that's faster.
Yeah, it's beneficial - a long as you don't get too "wound up" over a couple percentage points that aren't going to make the kind of difference that anyone would notice.
It's not the couple extra percent of efficiency and power I appreciate. It's the lots more initial torque. Starting uphill from a stop is where I most notice it. Also zipping across an intersection when there's a small break in cross traffic.
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John in CR   100 GW

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Re: Leafmotor project

Post by John in CR » Sep 28 2020 6:50pm

Balmorhea wrote:
Sep 28 2020 4:43pm
donn wrote:
Sep 28 2020 3:49pm
Balmorhea wrote:
Sep 28 2020 1:18pm
Others have different speed objectives, but it's always beneficial to get the right kV for the job, rather than one that's faster.
Yeah, it's beneficial - a long as you don't get too "wound up" over a couple percentage points that aren't going to make the kind of difference that anyone would notice.
It's not the couple extra percent of efficiency and power I appreciate. It's the lots more initial torque. Starting uphill from a stop is where I most notice it. Also zipping across an intersection when there's a small break in cross traffic.
You can try to justify your wrongness using apples to oranges comparisons all you want, but it's still wrong. Using any winding of the same motor to make more torque, the motor makes more heat (assuming same copper fill). It's simple physics. Slow wind motors are fine for those who are positive they never go faster, however, they are easier to push to heat failure on long hills because even relatively low power controllers can push enough current through their far higher resistance windings. They aren't more efficient on hills, they can't make more torque, they're simply slower and lower power. Your experience with apples and oranges comparisons has lead you to continually make factually inaccurate statements that are a detriment to the forum because it propagates the myth about a subject that is widely misunderstood.

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