Using leafmotor/leafbike 1500w as mid-drive motor?

nerdalert · Mar 23, 2015

Is there any reason why I cannot or should not buy a 1500w rear spoke motor from leafmotor/leafbike and mount a sprocket onto the 6 bolt threads for the disc brake for use as a mid drive motor on a velomobile project? What are the threads on the opposite side for? mounting a casette?

http://www.leafbike.com/products/e-...-spoke-hub-motor-electric-bike-motor-998.html

crossbreak · Mar 25, 2015

these threads are meant to mount a cassette... just like most hubmotors do. i conclude, you haven't used one yet. thats not a problem. i used my first hub in a middrive too
sure you can use it as a middrive. The good thin lamination and high speed wind is perfect for that. I eats around 95W no load @ 49V according to neptronix. http://endless-sphere.com/forums/viewtopic.php?f=30&t=66489#p1002581
so at 40mph in a 26" rim it should eat only 65W @ 540rpm no load. so there is lots of room to speed things up/gear it down, to get more torque from it and to get up steepest hills
I do suggest not to run the power through the bicycle cassette/ gear hub drive train, since it is not designed for this power. Better use another chain to the rear wheel with a ratio of 1:1.5 or so. Like if you would run it in a 20" rim.

What rim size do you aim on?

I suggest to move this thread into the bycicle/middrive section as it is not directly motor related. It's more about drive train

spinningmagnets · Mar 25, 2015

From Rassy:

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=18606

crossbreak · Mar 25, 2015

yep, this is exactly what it meant. It is not such a good idea to run such a big hub through a gear hub. It will kill it quickly. With such a small rim, the motor will perform well/climb hills well if it is simply laced into the rear wheel

crossbreak · Mar 25, 2015

it would be a good setup, if you'd lace this motot into a 16" moped rim with a relatively wide tire, like 16x2.5". This moped tire is equivalent to a 20" bicycle tire but performs a lot better (much more rubber dampens/handles pot holes much better)

neptronix · Mar 25, 2015

I don't know much about the hardware interconnections etc..
But this motor would be friggin' looney as a mid drive..

Run it at 2000W max all day and it will be real happy at about 88% efficiency.. best power per weight in a DD you can get in this size.

speedmd · Apr 21, 2015

How light do you estimate you could make one. Even if you had to replace major parts with remakes in lighter materials and designs. There would be no wheel loads to deal with. Axle could be hollowed/ shortened a bit/ ends square tapered for torque plate mount.

crossbreak · Apr 21, 2015

major material loss can be gained from stator iron i guess...just like all hubbies. Just as you say, there is a lot less stress on it. All eaten by the drive train. A belt at it's best

speedmd · Apr 22, 2015

Leave one side mostly open with sufficient support added on the shared drive/ mount side? Replace the stamped steel center support with a well thought out / machined aluminum alloy structure and a lager diameter possibly hollow cromo axle. Something that could easily fit heavy gauge phase wires. Guessing your Still looking at way more than a ten pound motor unless you thin out the outer ring and change mass of stator steel.

Punx0r · Apr 22, 2015

Without the requirement to support spokes you could likely thin down the backing iron quite a lot

crossbreak · Apr 22, 2015

isn't the spoke flange and side cover support structure made of aluminium alloy with cast-in backiron? guess the backiron is not as thick a one might think, as you check without cutting (and thus destroying) it. These motors are heavy, still they where optimized for weight.

neptronix said:
neptronix said:

best power per weight in a DD you can get in this size

Click to expand...

+1

i think it is not really worth the effort since it will never get lightweight by all of this :wink:

speedmd · Apr 22, 2015

Agree you will never make it light. You could however remove most of the aluminum in the spoke flange areas/ modify it for better heat transfer ( cooling fins) at the same time. Thin / port side plates also by significant amounts as well a skeletonize the stator support plate much further. Easily a few pounds if your willing.

Punx0r · Apr 22, 2015

Ah, I thought the spoke flange and backing iron was one piece of steel.

crossbreak · Apr 22, 2015

I dont have a leaf motor. But the only motor i know that has a one piece rotor is the conhis motor mini DD hun that is incredible heavy for its size

Punx0r · Apr 23, 2015

The 9C and clones do, Magic-pie, I think. Cromotors do as there was one chap on here who posted a significant weight saving from turning his down.

I think most direct-drive motors do. The manufacturer just turns a section of thick-walled steel pipe...

crossbreak · Apr 23, 2015

MagicPi2 doesn't. i have one here and checked it.

Punx0r said:
The manufacturer just turns a section of thick-walled steel pipe...

That would be a lot more expensive than doing a cast, at least for a large motor and a nameable production batch

Hope that nep or freeride give us some proof here!? Thx!

Punx0r · Apr 23, 2015

Obviously a less common practice than I assumed...

crossbreak · Apr 23, 2015

other thing is spinning up this thing. With 0.35mm laminations, 40k-erpm should be possible without excessive eddy currents. At 23 pole pairs this means 1700rpm :shock:

Meaning one could gear this at 3:1 for a motor speed of 1500rpm at a wheel speed of 500rpm (around 60kph or 38mph in a 26" wheel) and be able to easily haul big loads up any hill

I would not be surprised if it would take 5kW continuous this way.

speedmd · Apr 23, 2015

I was thinking it could easily take a taller ratio, something like a 14 or 15 to a 34 or 36 tooth sprocket setup with great torque and acceleration. Not crazy about the exposed spinning can.

crossbreak · May 4, 2015

freeride confirmed that the spoke flanges are actually made of steel :shock:

I'd have bet that they are not :oops:

--freeride-- said:
So, die Flansche sind tatsächlich magnetisch, also ist der Mittelteil aus Stahl, die Deckel sind nicht magnetisch und wohl aus Alu.

speedmd · May 4, 2015

Most likely you could turn it down and thin it a bit without giving up much magnet strength and also thin the spoke flanges a bit leaving some as cooling fins. May not be worth the work. Stator hub and axle may be where you could loose the bulk of the weight and narrow it down a bit also with mid drive design changes. You could include a much larger wire side bearing for large wire exit and more secure torque mount in it at the same time. Lots of work.

spinningmagnets · May 4, 2015

The MXUS V2 "9C clone" has a 28mm wide stator, and aluminum cast spokes, but...is not being stocked due to low sales, factory requires minimum order of 400 to make a batch (crap!).
http://endless-sphere.com/forums/viewtopic.php?f=3&t=67683
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$295 (plus T&S) ebikes.ca "new 9C" has 30mm wide stator, aluminum spokes, freehub...(price is for an unspoked bare hub)
http://www.ebikes.ca/news/nine-continent-cassette/
__________________________________________________________

Leaf motor has 35mm wide stator, cheap price, but...flat steel plate for center support of stator.
http://endless-sphere.com/forums/viewtopic.php?f=30&t=66489#p1002581
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Crystalyte 408, stokemonkey motor can be bought as a spare part, smaller diameter than the three hubs above...
http://www.ebikes.ca/shop/ebike-parts/motors/mstoke08.html
__________________________________________________________

The first three above have thin laminations, will fit 7 speeds, and the cable exits the axle inside the drop-outs, so...there has been some progress in the industry.

crossbreak · May 4, 2015

JohninCR has this nice 20pole mini monster with 0.35mm lams (http://endless-sphere.com/forums/viewtopic.php?f=31&t=40859)... it has really low parasitic loss. I abandoned it once since it has quite low KV (9KV) for the pole count (20). Both leaf and the MXUS 3000 V2 have about double the pole count (46?) and more KV (3turns=12KV in WYE). so these two motors are more interesting IMO

Still, the MiniMonster is more interesting for its size. I have to bump wheelbase to 130cm in an experimental concept to just fit the MXUS or leaf. I put 260 pcs of 18650cells in the frame to fit 13s20p or 20s13p >2kwh and 26" wheels to gain somre range.

This has nothing to do with a 3wheeler but maybe it shows how the difference in diameter of these motors may effect frame design/possibilities to fit them

Samd · May 17, 2015

spinningmagnets said:
The MXUS V2 "9C clone" has a 28mm wide stator, and aluminum cast spokes, but...is not being stocked due to low sales, factory requires minimum order of 400 to make a batch (crap!).
http://endless-sphere.com/forums/viewtopic.php?f=3&t=67683

A few of us do have a couple from the last batch but they are getting hard to find. Mine are set up as front motors.

ABritInNY · Dec 1, 2015

crossbreak said:
other thing is spinning up this thing. With 0.35mm laminations, 40k-erpm should be possible without excessive eddy currents. At 23 pole pairs this means 1700rpm Meaning one could gear this at 3:1 for a motor speed of 1500rpm at a wheel speed of 500rpm (around 60kph or 38mph in a 26" wheel) and be able to easily haul big loads up any hill

I would not be surprised if it would take 5kW continuous this way.

When my wheel is set as 2160mm (measured with string) and 23 pole pairs my speedo is about 3-4 mph under, when I change to 20 pole it evens out with my brothers motorcycle speedo alongside me... Are we sure the 1500w leaf has 23poles as the CA v3 setup? why is my speedo wonky then? confusing...

Using leafmotor/leafbike 1500w as mid-drive motor?

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