# High torque hub motors?



## jawnn (Oct 10, 2013)

I am searching for hub motors that will take 12 volt dc. What do solar cars use? 
Would an extra wide hub motor have more torque?
I want to build a very light weight motor trike or very heavy tricycle, about 450-550lbs total combined weight. 
We have very steep hills up to 16% grades. 
I am thinking about a voltage switching rotary switch, 12 volts for hill climbing and higher voltage for cruising.


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## jawnn (Oct 10, 2013)

*what to do*

so the best ones I could find are 5 to 1 gear reduction. I think there must be a way for a motor cycle to use a motor with out loosing so much power in the gears. 

A hub motor made for more than a bicycle is needed. we have steep hills here, minimum of 9 percent.


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## major (Apr 4, 2008)

*Re: what to do*



jawnn said:


> I am searching for hub motors that will take 12 volt dc. What do solar cars use?
> Would an extra wide hub motor have more torque?
> I want to build a very light weight motor trike or very heavy tricycle, about 450-550lbs total combined weight.
> We have very steep hills up to 16% grades.
> I am thinking about a voltage switching rotary switch, 12 volts for hill climbing and higher voltage for cruising.





jawnn said:


> so the best ones I could find are 5 to 1 gear reduction. I think there must be a way for a motor cycle to use a motor with out loosing so much power in the gears.
> 
> A hub motor made for more than a bicycle is needed. we have steep hills here, minimum of 9 percent.


Hi jawnn,

No replies yet. Bicycles aren't too big on this board. And hub motors not too popular. But you are talkin' EV, so the basics do apply and you should gain some help here. You might try using some calculators from the wiki to figure the power and energy needed for those hills.

To address some of your points:

Why 12 volts  It will be very difficult to use 12V. You rarely see a 12V propulsion system in excess of a few 100 Watts. And efficiency will suck at higher power.

Solar cars (those high dollar competition EVs) use higher voltage, expensive motors and don't mess about with hills or high torque as far as I know.

Motor torque is proportional to size in most cases, so a wider motor is likely to have more torque.

I don't know why you think a rotary switch would be of any use. You'll need a motor controller.

And I don't know why you think you lose much power in gears. They are in fact very efficient and well worth it when it comes to torque  Also consider a small diameter drive wheel for hill climbing torque.

I don't want to send you away, but a good resource for electric bikes is ES. http://endless-sphere.com/

Good luck,

major


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## jawnn (Oct 10, 2013)

*Re: what to do*

*This is a proto-type of a very light weight car, not a bicycle.*​ 
*What I need is a hub motor that will take high amperage at low voltage. Yes; and the right controller to do that.*​ 
*This is the kind of hub motor I am thinking about, a high tech concept with variable field magnet *
*http://www.youtube.com/watch?v=6_41btVawMc *​ 
*I want to get away from gears because they weigh too much.*​


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## major (Apr 4, 2008)

*Re: what to do*



jawnn said:


> *This is a proto-type of a very light weight car, not a bicycle.*​
> *What I need is a hub motor that will take high amperage at low voltage. Yes; and the right controller to do that.*​
> *This is the kind of hub motor I am thinking about, a high tech concept with variable field magnet *
> *http://www.youtube.com/watch?v=6_41btVawMc *​
> *I want to get away from gears because they weigh too much.*​


For a given torque requirement, combination of motor at higher speed using gears will weigh less than slower motor without gears.


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