12 turn Hub-motor vs Mid-drive for hill climbing ??

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Hugh-Jassman   1 kW

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12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by Hugh-Jassman » Feb 19 2019 2:58pm

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I think someone should do a comparison test between a mid-drive and a hub motor with 10 to 12 turn winding with or without gears. How much energy would it actualuy use in a given hill climbing compairison. Same total combined weight, speed and steepness of grade? With the price of batteries being so high I think this would be a good thing to know.

I think the only way to build a gearless power system with hub motors would be to use two; the front wheel would need a 5 turn winding and the rear a 12 turn winding, then literaly switch between them. This would be good for hauling a total combined weight of 500 to 600lbs on the same steep hills. But if there is a weight limit of 200lbs on each hubmotor I would need three wheels.

After setting up my CycleAnalyst I drove my bike with Cyclone3000 up the short hill up to my house with two arm loads of fire wood in my trailer [about 450-475lbs total combined weight] while in the high gear [11:1 ratio] drawing about 1400watts then in the low gear drawing only about 600watts [20:1 ratio]. For most hills I use a 16:1 ratio making it 3 seperate gears that I use. [My drive wheel's tire is 23” diameter. The ratios include the 6:1 planetary gear reduction in the motor.]

No-one ever says anything about how little power is needed. I would really like to hear from someone with a 5:1 geared hubmotor with at least 10 turns. A voltage multiplier is just a way make it possible to burn more amps.

I have been using around 37 to 43 Wh per mile depending on whether I climb a hill or not. Averaging 10.2 mph. I must recharge for 45minutes at the food-co-op before driving home. Because my 52v battery is only 13.5 amp hours that cuts off at 39 volts, and I charge to only 90% before leaving on my trip to town. Aprox. 10 miles round trip.

The Cyclone can out put 3000w only at 72volts and I don't want to get anywhere near that.

Does any one know if the Cyclone Mini is a faster RPM motor, thereby needing the larger 9.55 to 1 gear reduction?? or did they do that to make it more street leagal.

Grantmac   100 W

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by Grantmac » Feb 19 2019 3:27pm

What are you trying to achieve? Faster speed on that hill? Less overall battery use?

billvon   10 MW

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by billvon » Feb 19 2019 4:32pm

Hugh-Jassman wrote:
Feb 19 2019 2:58pm
I think someone should do a comparison test between a mid-drive and a hub motor with 10 to 12 turn winding with or without gears. How much energy would it actualuy use in a given hill climbing compairison. Same total combined weight, speed and steepness of grade? With the price of batteries being so high I think this would be a good thing to know.
There are so many ways to compare that would be hard. Varying hill steepness or one fixed grade? (hubmotor can be optimized to one grade) Downhills? (no regen in geared hubs or mid-drive so no energy recovery.) Top speed on flats? Efficiency on flats? Etc.
--bill von

district9prawn   100 W

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by district9prawn » Feb 19 2019 6:02pm

A good start would be to compare the resistive losses of the motors from their kv/kt and winding resistance when they are making the same torque at the wheel.
Neu 8057 6kW left hand drive hardtail: viewtopic.php?f=6&t=96754

markz   100 GW

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by markz » Feb 19 2019 9:17pm

A 12T motor is not good because a 12T would have very long wires that are really thin compared to a 4T which has shorter wire that is really large which can take more amps, more amps means more power. Then to get some added torque, you just reduce the circumference of the wheel, say go from a 26" to a 24" or smaller.

There is no difference between a 12T and a 4T other then mentioned, the 12T does not give you more torque because the 4T can do exactly the same by playing with the settings, installing thicker phase cables/battery cables reducing the resistance even more.
We discussed it to great lengths here...
https://endless-sphere.com/forums/viewt ... &start=625
yes its in there somewhere

Triketech   1 kW

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by Triketech » Feb 19 2019 10:52pm

I did something similar with a trike.

Mid drive won over a geared hub but I prefer the geared hub.

http://www.triketech.com/Drivetrain/Pow ... Drive.html

http://www.triketech.com/Drivetrain/Pow ... AC-V2.html

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Chalo   100 GW

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by Chalo » Feb 19 2019 11:52pm

The difference between the two kinds of motor for hill climbing is that you can configure a hub motor for a certain steepness and load, but you can potentially set up a mid-drive for any steepness and load.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Hugh-Jassman   1 kW

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Re: 12 turn Hub-motor vs Mid-drive for hill climbing ??

Post by Hugh-Jassman » Feb 20 2019 2:08pm

very inlightening, thanks...I will read more

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