Most powerful Direct drive Hub Motor?

[Gorillazilla]

Here's a question and a half! thanks for your time +1!


What would be the most powerful Direct drive Hub motor with the most torque for hill Climbing that is not made in China?

Top speed not too important, no more than 20 MPH, Just Maximum torque for climbing hills and highest efficiency while cruising safely at around 20 MPH (preferably using higher quality .30mm stator laminations for higher 95%+ efficiency like the Leafmotors do)

I know Mid Drives are better for climbing hills, but greatly increase Drivetrain wear and hassle.

I'd prefer Direct drive over geared hub, for Silence, Simplicity, and longevity, as well as regenerative braking for that little bonus of 5 to 8% extra range, and the bigger bonus of not wearing out brake pads so much.

I'll be using it on a Hard tail mountain bike. I took a look at the Cromotor but it's so wide that you loose all your gears and the newer versions are actually manufactured in china now rather than Croatia where they were originally made. Is there anything similar out there only made somewhere else than china and a little slimmer so I can keep my gears?


Cheers!

 

[Benjahmin]

Any direct drive motor capable of giving you 20mph will be highly inefficient at climbing hills. It's best efficiency will be at 20mph, anything slower and inefficiency ramps up. Anything below 10mph there will be large amounts of heat produced, so eating your battery to no useful effect and straining the motor.
To run a 1kw motor at 1kw you would need a controller cpable of 27.7A @36v - so a 30A controller. To do this the battery must be capable of delivering 35-40A max. Expensive !
Don't get hung up on big number motors. The motor rating is merely the continuous rating and is fairly meaningless.
Here's an example. A 250W geared hub run on a 17A controller will give a nominal 612W @36v. If you go to 48v this becomes 816W. So a 36v motor run at 48v will give you higher top speed. However this will be at the expense of torque. Running a 17A controller means you can have a 20-25A battery, much more achievable.
You're going to have to make your mind up. Do you want high top speed or hill climbing ability. The two are, at least partially, mutually exclusive.
Regenerative braking on a bike is not worth the extra expense of control circuitry. Bikes simply do not have the mass to make it work effectively. Add to that the extra drag from magnetic resistence in a DD motor making very heavy to peddle with no power.
If you want a hybrid mountain bike then geared rear hub is best.
If you want a full on hill climbing mountain bike then crank drive is the way to go.
Leave DD motors for those who live in Norfolk.

 

[Nealh]

It would probably be a Heinzman but whether it is actually 100% produced in the land of the Bosc I don't know.

 

[Gorillazilla]

Any direct drive motor capable of giving you 20mph will be highly inefficient at climbing hills. It's best efficiency will be at 20mph, anything slower and inefficiency ramps up. Anything below 10mph there will be large amounts of heat produced, so eating your battery to no useful effect and straining the motor.
To run a 1kw motor at 1kw you would need a controller cpable of 27.7A @36v - so a 30A controller. To do this the battery must be capable of delivering 35-40A max. Expensive !
Don't get hung up on big number motors. The motor rating is merely the continuous rating and is fairly meaningless.
Here's an example. A 250W geared hub run on a 17A controller will give a nominal 612W @36v. If you go to 48v this becomes 816W. So a 36v motor run at 48v will give you higher top speed. However this will be at the expense of torque. Running a 17A controller means you can have a 20-25A battery, much more achievable.
You're going to have to make your mind up. Do you want high top speed or hill climbing ability. The two are, at least partially, mutually exclusive.
Regenerative braking on a bike is not worth the extra expense of control circuitry. Bikes simply do not have the mass to make it work effectively. Add to that the extra drag from magnetic resistence in a DD motor making very heavy to peddle with no power.
If you want a hybrid mountain bike then geared rear hub is best.
If you want a full on hill climbing mountain bike then crank drive is the way to go.
Leave DD motors for those who live in Norfolk.

So I could have a Direct drive wound for torque, with an efficient speed range around 15MPH, and large and powerful enough to maintain 15MPH on a 15% grade?

Keeping it in its efficient range uphill?

Could any direct drive handle a hill like this efficiently if made for Torque over speed?

Marine Dr, Llandudno to Summit Cable Car Station, Llandudno LL30 2XE - Google Maps

Does not really need to be faster than 15mph because aiming for maximum range at lower speeds

 

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[Woosh]

So I could have a Direct drive wound for torque, with an efficient speed range around 15MPH, and large and powerful enough to maintain 15MPH on a 15% grade?

theoretically, yes but it will be very inefficient to build and operate.
The energy stored in each motor pole is defined in this formula:
w = 0.5 * LI2 (self inductance x current squared)
If your direct motor has 48 poles, it produces 48 x w at every turn of the wheel.
If your motor has a 1:4 reduction gearbox, your motor will do 4 revolutions for 1 turn of the wheel. You only need 12 poles to produce the same amount of energy. That's why geared motor is much smaller and also lighter.

 

[Gorillazilla]

theoretically, yes but it will be very inefficient to build and operate.
The energy stored in each motor pole is defined in this formula:
w = 0.5 * LI2 (self inductance x current squared)
If your direct motor has 48 poles, it produces 48 x w at every turn of the wheel.
If your motor has a 1:4 reduction gearbox, your motor will do 4 revolutions for 1 turn of the wheel. You only need 12 poles to produce the same amount of energy. That's why geared motor is much smaller and also lighter.

Thanks! That makes a lot of sense, each pole can only generate so much torque so all you can do to get more is to spin em faster and gear em down.

So geared hubs or mid drive are the only real options for serious hill climbing then, what would be the most efficient geared hub (not made in China) that could handle this linked route with ease?

> Marine Dr, Llandudno to Summit Cable Car Station, Llandudno LL30 2XE - Google Maps <

 

[Benjahmin]

Good luck on finding anything not made in China. Bosch, German branded - made in china. Can't think of any others.
Is this some ethical bias or a reliabilty/quality thing?
My own front hub is a chinese made Ezee. Since 2014 it's done around 14,000 miles. How much reliability you looking for?
As for efficiency. Run the motor as close to modal speed as possible and you'll get best efficiency. Obviously, when hill climbing, speed will be less - so efficiency less.

 

[Woosh]

So geared hubs or mid drive are the only real options for serious hill climbing then, what would be the most efficient geared hub (not made in China) that could handle this linked route with ease?

this is a steep climb, crank drive is the best choice for it.
You will have to pedal a fair bit to get to the top.

 

[Gorillazilla]

this is a steep climb, crank drive is the best choice for it.
You will have to pedal a fair bit to get to the top.

Cheers! I went with this route


Picked up a Taiwanese made Cyclone 3KW from here: https://www.cyclone-tw.com/product/6/data/17

Should be able to climb up any hill on the small 32T chainring


And leaves open the option to run a small direct drive on the rear wheel, something of high quality and specialised completely for maximum efficiency cruising at 15 on the flat

Should be worth the extra weight

Plus should be interesting to test the dual motor concept which is:


Huge battery as large as will fit in the Triangle frame, Top 44cm / Front 54 cm / Rear 37 cm

Small 100% specialised for efficiency direct drive on the rear hub for 15mph flat road cruising, maybe even with a sinewave controller for even more efficiency and silence, direct drive also bipassing drivetrain losses and wear.

Powerful mid drive for climbing any hill with shopping, or hauling a trailer

Plus both motors can work together on the hills.




Battery next, so I'll be getting in touch with Jimmy over at INSAT for that

eBike Batteries

ebikebatteries.co.uk

 

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AM Racing AMR 250-90 Single AC Motor - Liquid Cooled, Permanent Magnet - Remy Cartridge, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

www.evwest.com

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[Gorillazilla]

AM Racing AMR 250-90 Single AC Motor - Liquid Cooled, Permanent Magnet - Remy Cartridge, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

www.evwest.com

woof

 

[Woosh]

Cheers! I went with this route


Picked up a Taiwanese made Cyclone 3KW from here: https://www.cyclone-tw.com/product/6/data/17

Should be able to climb up any hill on the small 32T chainring


And leaves open the option to run a small direct drive on the rear wheel, something of high quality and specialised completely for maximum efficiency cruising at 15 on the flat

Should be worth the extra weight

Plus should be interesting to test the dual motor concept which is:


Huge battery as large as will fit in the Triangle frame, Top 44cm / Front 54 cm / Rear 37 cm

Small 100% specialised for efficiency direct drive on the rear hub for 15mph flat road cruising, maybe even with a sinewave controller for even more efficiency and silence, direct drive also bipassing drivetrain losses and wear.

Powerful mid drive for climbing any hill with shopping, or hauling a trailer

Plus both motors can work together on the hills.




Battery next, so I'll be getting in touch with Jimmy over at INSAT for that

eBike Batteries

ebikebatteries.co.uk

How heavy are you? If you weigh under 16 stone, I think road legal crank drives will do.

 

[Gorillazilla]

How heavy are you? If you weigh under 16 stone, I think road legal crank drives will do.

Has to be capable of tackling those hills with not just me but a full load of shopping, and potentially a trailer.

Kit arrived yesterday, but won't be assembling it onto the bike until I have everything I need, Still need the battery and charger.