Gen2/Regen

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Regen refers to Regenerative Braking

Operation
The Sevcon Controller can enter a regeneration mode where it captures momentum from the motor and charges the battery.
The battery must accept incoming power for this feature to work, and the controller must manage the process.
Operating Range
Regen for Zeros operates between 12mph (where the motor cannot produce enough voltage to naturally power through the controller) and 4500 RPM (70mph in default gearing).
This band can be adjusted in MBB settings.
Level
Regen levels are defined/set in terms of percentage of maximum allowable levels, so 0-100%.
That 100% maps to a 40A recharge limit setting in the Sevcon controller, equivalent to 10% of the maximum discharge rate of a Gen4 size 4 controller.
The 100% setting also corresponds to 60% of the 72Nm torque limit also specified.
The recharge limit may be set up to 91A via Sevcon setting or higher by a dummy value (65535?).
Zero sets regen levels to preclude rear wheel lockup, so raising the limit is a risk that ABS cannot directly control.
Regen has the same effect for SR/DSR models as for S/DS.
Efficiency
The recharge efficiency of regen is typically that 10% of the energy used to climb an incline can be returned on the corresponding descent.
Triggers
  • Normal regen is triggered by relaxing the throttle.
    There is a position just above the resting position where an actual neutral torque is achievable.
    The MBB has a setting in mV for the potentiometer output of the throttle to trigger regen.
    Adjusting this is not normally effective unless changing throttle types.
  • Brake regen is triggered by the same signal that turns on the brake light:
    A contact switch against the front brake lever will engage the brake light (and regen); the hydraulic piston and the switch engage simultaneously by default.
    Rear brakes engage pad contact and the brake light (and regen) simultaneously, but require some amount of travel before they engage.