1kW brushless RC Motor vs 1kW (big) brushless motor E-Bike

Hey guys,

What are the differences between RC BLDC motors and regular (big) BLDC motors?
Lets take the following as an example:

I would assume there are several differences between the motors below. If so what are they for example in torque?
1. http://www.ebay.com/itm/BRUSHLESS-MID-AXIAL-MOTOR-48V-RATED-1000W-VAE-E-BIKE-QUAD-CAR-e-SCOOTER-/201301830521?pt=LH_DefaultDomain_0&hash=item2ede862b79

2. http://www.hobbyking.com/hobbyking/store/__19617__Turnigy_L5055B_600_Brushless_Outrunner_600kv.html

I am planning on using a BLDC motor on an E-bike I am looking at something in the 1000W to 2000W range for the regular motor. What motor should I choose? Any suggestions are welcome.
Are any RC motors Viable since I have seen people use them on youtube and they seem to work quite well? Also keep in mind the long battery life would be a plus.

Best Regards Glenn

Motor that works on higher rpm can be physically smaller.

RC motor you linked spins at ~18000 rpm. Can you handle that?

Well that is a lot but let's say that you geared that down for an electric bike, which motor would have the most torque the big 1kW motor or the RC motor?Basically what I want to know is if two motors of equivalent wattage have the same torque i.e. an RC motor and a regular big motor.

Thanks for responding

Yes, once you gear it down to same wheel rpm, they have same torque. That is because power equals torque times rpm, and since rpm and power are the same, you get the rest.

Practical differences are that the rc motor is much ligher but much harder to implement on bike, and larger motor has larger thermal mass so it will withstand more than rated power, which cannot be said for rc motor.

Thanks a lot for your reply.

So how much can you 'over watt' the big motor is there a rule of thumb kind off? Currently I am looking at the big 1kW motor that I linked earlier and a 3kW motor from golden motors Either I am going to make an e bile with 1kW or a dirt/trails bile with 3kW. Any thoughts?

Thanks

A lot :lol:

You can see info you want here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483

Thanks a lot I will give it a detailed look tonight

No I am planning to make my own controller for the motor as a project for my collage. NO BLDC motors don't need pure sine waves right since the motor's coils' inductance smooths that out on it own correct? I am planning to give it a wave like tone attached. That should work correct?

Best regards Glenn

Yeah, it should. But trust me, making succesfull controller is far more comlicated than you think, and you have awful lot to learn, sometimes it's not worth it, especially for just one college project. Maybe you could seek something simpler, like analogue battery charger.

Well it has to be complicated since after this course I will move on to my degree. I am going to use a microcontroller to control 6 transistors to generate the needed waves. I have done ample research and it should not be that tough to do with the knowledge I have. Having said that obviously I am expecting unexpected problems which will make swear a lot but if I work hard I will over come them.

You seem to know your stuff can you recommend a battery pack for a 3kw motor.

I have found a battery pack 48v 15ah with a 50A constant discharge which would not be enough for 3kw but its decent. However it will cost 500usd to get to my door.

I have also found a 6s 16ah pack from
at 85 euros and I was planning to connect 2 of them in series. That will give me more than enough constant discharge however it would be 44.4v.

Another option would be to buy single cells and make my own pack. I have found 10ah cells from headway at 20$ a pop IIRC.

Any recommendations?

Thanks for your help