Regen Braking Brake Lights ??

[MadBaz]

While driving in Regen 3 mode today l was pipped a couple of times from drivers following me , l presume it’s because my brake lights are not coming on under braking. Does anyone know for certain if they do come on or not please ?

 

[MG Clive]

I think we decided in this previous thread that they didn't come on, but I don't think it was conclusive.

 

[siteguru]

If the retardation rate exceeds are certain amount (1.3 m/s²?) then they have to come on. If they don't then it's a fault.

Perhaps you were getting bibbed because your brake lights seemed to be coming on erratically? (i.e. to the person behind it seemed like you were braking/accelerating/braking/etc.)

 

[dStan]

I checked yesterday actually, and on regen 3 they do light up. But it depends also on speed/deceleration, so perhaps siteguru is correct, that it depends on retardation rate.

 

[siteguru]

It absolutely does - it's in vehicle standards regulations. From a thread on SpeakEV:

The threshold in the UK is deceleration >1.3m/s^2 the brake light signal must be generated. Between >0.7m/s^2 and ≥1.3m/s^2 the brake light signal may be generated. Below that threshold, the brake signal should not be generated.

... and this is defined in UN Regulation No. 13-H Stop Lamp Illumination (PDF).