brushless motors

[richie-rich]

Hi all,
Has anyone tried using an rc model brushless motor?
They are available in many sizes up to several kW. A 1.6kw motor is only 30 quid.
The rc stores also have lots of battery options...
I am trying to see where the 2000 quid goes in an electric bike!

 

[Deleted member 4366]

You need a reduction system to get the speed down to wheel-speed. Also, most of them don't have hall sensors, so you have to use an RC speed controller, which then needs additional electronics to fit a throttle, plus the speed response is not very accurate. By the time you've done all that, it's not so cheap.

If you have a look on Endless-Sphere, some people have overcome all the problems and done some nice installations.

 

[richie-rich]

I will have a Google about. I found a bit of info on electric bike.com

I have designed speed controllers for brushless motors before so that bit is no problem for me.

You're right about the motor rpm being high for a bike. I guess some reduction and a mid motor mount might be an option.

I actually designed a controller that could run a brusless motor down to zero rpm so it be interesting to try it out. (Even got a patent for it!)

Anyway its all interesting stuff!

Cheers.

 

[trex]

the reduction system is the easy bit - plenty of choice off the shelf.
Big problem is, if you lower the RPM, you lose efficiency and torque big time. Efficiency is the main attraction of RC motors, the weight of the motor is not that important.
Even if you could control the RPM without Hall and solve the torque problem with a CVT, it's very difficult to compete commercially against current crop of efficient crank motors.

 

[flecc]

Even if you could control the RPM without Hall and solve the torque problem with a CVT, it's very difficult to compete commercially against current crop of efficient crank motors.

Particularly where noise is concerned, an area which is increasingly important to e-bikers now.