VESC Throttle Idle

[cocolino]

Is there any way to make ADC throttle idle after release ? Thing is, I want to maintain constant tension on the drive chain in my mid-drive ebike. The way that I imagine it work is: when press throttle, accelerate, then release for few second, motor will maintain rotation on some low level, like 10-20W. Just enough to spin but, unable to move the bike. Of course, idle should cut off after ADC brake input and resistance from stopped in place.
Much appreciate any help in this topic.

 

[eee291]

You could switch a resistor between 5v/3v and throttle signal to achieve this effect, or lower the dead-zone and disable safe start,
When you are at a standstill you could deactivate the switch or keep the brake pressed.
Just know that I don't recommend doing either, do this at your own risk.

 

[scianiac]

Even long before starting to build this bike I thought a feature like this might be useful and as it turns out it is very nice. I've just set the throttle voltage range and deadzone (no deadzone) so there is just enough torque to spin the motor. I have killswitch and will add a brake switch at some point. It was actually easy enough to adjust the voltage range start so it can spin the motor but not really provide any forward power, it's not enough torque to move the bike on flat ground so you just roll to a stop as normal only ever so slightly slower. Still not totally safe because the throttle voltage could vary from some fault but it could do that outside of the deadzone in a traditional setup to. And of course throttle response is dramatically improved.

It's interesting that this solution isn't mentioned much, although I think the phaserunner has a similar option. As while it's not exactly idea to use power to do nothing but spin the motor and not gain anything back in regen it seems the power consumption is not enough to be a real issue and on many converted mid-drive bikes you just can't use regen due to suspension design. This also solves the freewheel engagement problem where by a powerful mid-drive can accelerate fast enough that if you're moving the motor spins up to match the wheel speed but in the small slack before the ratchet engages the motor spins slightly faster and then has to rapidly decelerate once the ratchet is engaged causing a high shock load on the clutch.