In the meantime I changed to a current throttle. Thanks to Grin for selling me their great CA and documenting it well, and thanks to Methods for well describing the tuning of the throttle.
There are multiple factors in play that determine the reaction of the motor to a change in throttle input when using current-throttle via the CA.
- Actual turning of the throttle by the driver
- Throttle output at a given rotation, typically measured at bottom and top
- Output of the CA at a given throttle input
- Output of the controller at a given input from the CA
- With the throttle connected directly to the controller, I listened to the motor at what throttle voltage it would start to turn (1.56V), with the voltmeter on the black and white wires.
- Methods also describes that you should be able to hear the controller switching from PWM to constant output. I did not know what to listen for, so I left this step out.
- Opened up the CA
- Entered 2x 3-wire throttle wires into the case - one with a connector to the controller, the other with a connector to the throttle
- Soldered the red 5V ends of both wires to each other
- Soldered the black grounds of both wires to the ground pad on the CA
- Soldered the white throttle signal from the throttle to the Vi pad on the CA
- Soldered the white throttle signal towards the controller to the Th pad on the CA
- Added ground / 5V source to black and red throttle wires
- Measured throttle output (0.826V – 3.7V) with the voltmeter on the ground and signal wires. Bottom output would vary a bit between 0.820 and 0.840V.
- Set (CA-manual section 8.17) Aux Voltage Function to current.
- Set (6.5) max amp to 60A
- (Almost) eliminated slop at the bottom of the throttle by setting 8.18 AUX threshold to 0.85V to allow for the variability in throttle bottom output. In other words, setting the AUX threshold to 0.84V would sometimes have the motor start running as soon as I left the settings-panel in the CA, without giving throttle. I tried different settings, but setting the AUX threshold at 0.85V would give me the best balance between ensured no-running motor at no-throttle and almost elimination of bottom slop prior to start of the motor.
- Set 8.12 iTermMin to 1.55V and 8.11 iTermMax to 3.3V. I did not change any of the feedback gains because I am happy with how the motor reacts to the throttle input.
- Almost no slop in the bottom of the throttle.
- Almost no slop in the high end of throttle input.
- much better control over acceleration. Low throttle input means low acceleration, whereas high throttle input means a LOT of acceleration (up to 80A peaks without limiting)
- Still needs careful management of throttle when starting from standstill.
- Maximum Amps according to the CA are indeed below 60A. No more 80A peaks anymore
In the V2 “Large Screen” version of CA, current-throttle works like a charm. I am currently attaching another throttle to my beta V3 CA, and adding some more connectors to make it an easy plugin into my bike. We will see how the V3 makes the throttle even better manageable.