The problem is the startup delay,
you hop on and pedal, then hit the power switch,
and regardless of throttle position the regen brakes
hit full blast until the controller initializes.
It takes a few seconds, but that means a screeching halt
while you wait for the 'click' after pressing the red button.
Ok, I'm no electronics expert, but could you have
three relays cut out the field coil (power) connections
between the controller and the motor?
When I don't want regen, I probably don't want power either.
The sensors will probably freak and send 'more current'
request to the controller, but with an open circuit you get
zero amps out.
Elmer.
Ebike in a state of flux. Now=.5kW kit with 3xSLA on the cheapest bike I could get.
The next order is a kW front wheel on a $60US Diamond Back Cruiser
with an under-published 48V20AH LiFePO4 pack.