Outrunners... what's the catch?

After doing research, it looks like a 2 speed helps a lot for these. Either that or a current limiter. Current limiters should help with efficiency a lot and extend the life of all your parts, because stalling / near stalling on outrunners is very bad.

For a pedaless tradpole I'm building I'm going with a current limiter to limit my system to 3600 kw max, probably will do 1 speed since I'll be using a belt. It won't be a true current limiter though, I think I'll have it reduce throttle when the current limit is exceeded for longer than 1/10th of a second. The tadpole will be higher and wider than normal tadpoles so it can handle the higher speeds on the streets safer.
 
Long time since I posted the previous post, just as an update I ruled these motors out. They are sensorless, which means they are extremely inefficient at lower speeds. So any application where low end torque is needed (road vehicles) I would be cautious.

On a pedal bike I wouldn't engage throttle on one of these until you are doing several mph.
 
Long time since I posted the previous post, just as an update I ruled these motors out. They are sensorless, which means they are extremely inefficient at lower speeds. So any application where low end torque is needed (road vehicles) I would be cautious.

On a pedal bike I wouldn't engage throttle on one of these until you are doing several mph.

Not sure where you got your info, but its not right.

Brushless outrunners are far more powerfull and efficent at low rpm, and at there worst, are usualy better than a brushed motor at its best.

As for sensorless, that has nothing to do with efficancy. a sensorless controller uses the phase wire's back emf pulse as the motor turns for a sensor, instead of an external sensor
 
Hey Guys,

I am the owner/builder of the E-cumbent posted earlier.

Brushless, sensorless outrunners are very good for bike use. There really isn't a down side (or a catch) other than they are not designed for bike use and, therefore, more difficult to mount.

I am getting 13wh per mile at 15mph and 17wh per mile at 20mph.

Also, I pull 5,000 watts easily without the motor running hot. 0 to 35mph in 7 seconds without trying hard.

Startup and low speed tractability is fantastic. No pedalling needed to start the bike. The motor just starts and runs smoothly. Most of that is the controller programming.

My entire system (motor, lipo pack, reduction unit and related equipment) is 12 pounds.

I hope that helps answer some the questions!

Matt
 
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