Regen and Brake Lights

In the Chevy Bolt, a question that comes up quite often is whether or not the brake lights are illuminated when the car is regenerating power. Also, since we have one-pedal driving which can bring the vehicle to a complete stop – do they continue to stay lit when stopped?

Although I do not know this for absolute certain, I believe that the Bolt Regen lighting meets WP.29 (UNECE) standards for lighting:

5.2.22. Generation of a braking signal to illuminate stop lamps Electric regenerative braking systems as defined in paragraph 2.17., which produce a retarding force upon release of the accelerator control, shall generate the signal mentioned above according to the following provisions:

Vehicle decelerationsSignal generation
≤ 0.7 m/s²The signal shall not be generated
> 0.7 m/s² and ≤ 1.3 m/s²The signal may be generated
> 1.3 m/s²The signal shall be generated

1.3 m/s² is 2.9 mph/sec or 4.7kph/sec deceleration.

Full L Regen + paddle is about 3m/s² or 6.8 mph/sec or 11 kph/sec. A hard brake is about 10mph/sec. Skilled drivers can do 14. Vehicles tend to top out at about 15.

In all cases the signal shall be de-activated at the latest when the deceleration has fallen below 0.7 m/s².

Specifically all of this can be seen on page 335/18.

Note that this is *commanded* regen. If you are going down a hill, you could be accelerating and the brake lights will still illuminate since the car is regenerating, despite not slowing the car down.

Unfortunately, the brakes do not stay lit when stopped. I don’t know why they decided not to do this, I can only assume that since the above requirements do not call for it, they decided not to bother. It seems like it would have been an easy thing to do.

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