Finally got the new road bike rolling today. I wanted this bike to be even lighter then my last road bike so the only way this was going to happen was to stick with a 50mm motor rather then a 63mm and use a smaller battery pack. Tried two 50mm motors, A Keda 230kv motor and an even smaller Turnigy SK3 5055 280 kv motor. With an ebike controller, the Turnigy motor struggled and was quite loud. However, with the Vesc in FOC mode, what a difference.
The little SK3 has transformed into a really sweet motor. Using the Vesc in FOC easily halved the noise that I have experienced with any other motor using a stock ebike controller. It is not going to break any power records, but its adequate for what I want to do.
In total I have pulled 700 grams off the bike. Doesn't sound like much but on a bike like this, its close to 10% of the total bike's weight. I am now running a 7S2P pack using 3500mah 18650 cells so this knocks off 400 grams and the motor is only 370 grams so this takes another 150 grams off the total weight. Other 150 grams comes from the lighter speed controller. Also got the 2 button throttle going nicely which gives me either 50% current or 100% current. Running the reduced current more then makes up for the reduction in battery capacity.
So the Vesc is a real winner. I was sceptical about what difference running FOC on a sensorless RC motor would make. And when bench testing, the motor was noisier in FOC mode then BCLD mode. However, under load, the motor is significantly quieter. I would say at least 50% quieter. Other wins are that the motor is definitely smoother and can take off from really slow speeds, in fact I think it would take off from a dead stop if I wanted.
For the sake of an extra $60 or $70, I would recommend the Vesc over and ebike controller any day. It is in my opinion, the prefect match for this friction drive.
I will post up some video with sound tomorrow to demonstrate the difference in noise.