After a little experimenting, the regenerative braking settings seem to be dialed-in. Currently, the Kelley KHB 72701 controller is set at 10% braking upon throttle release and 25% braking upon brake switch activation. The brake switch is wired to the standard brake lights so a slight touch of the brake pedal will raise the braking power limit to 25% from 10% when the gas is released. This % is the percent of the controllers maximum current (700A). So far I only observed a maximum of 1500 watts of regen power and that only lasts for a few seconds before the car has slowed.
These settings provide reasonable engine braking and normal braking levels for coming to a stop. It seems the braking power is proportional to the speed which makes for a smooth braking experience. Since the voltage generated by the motor is proportional to the RPMs of the motor, as the car slows, the voltage drops reducing the amount of current that can be generated by the motor-controller.
The 10% throttle setting also allows the braking to come on slower than jumping right to 25%, which was jarring.
The Arduino on the dash is now reporting both power consumed (watts x time) and regen power. It looks like with my normal city commute, regen is providing about 5% back to the batteries. Not a lot but with a 25 mile range this is maybe a mile extra for a full charge. I guess regen is really more psychological and mechanical brake-saving than real range extension. It is a fun thing to talk about...
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