From Unofficial Zero Manual
Regen refers to Regenerative Braking
- 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.
- 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.
- The recharge efficiency of regen is typically that 10% of the energy used to climb an incline can be returned on the corresponding descent.
- 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.