Carsten Haase
Well-Known Member
I was thinking about this fact today - if you start up a steep slope without applying additional power (or even applying less power, but still some), such that car slows rapidly, do the brake lights still come on? Or is it some combination of pedal position and accelerometer reading that triggers them?
Somebody want to mount a drag chute on their SE and pop it open at max speed find out?![]()
I very much doubt it's controlled by an accelerometer.
Since the brake lights are a safety system and federal requirement, the controller/software almost certainly is ASIL rated and I don't think an accelerometer would be able to satisfy those requirements.
The ECU knows exactly how much regen is happening because it's being directly determined by the inverter (it has to know to determine acceptable current level for the batteries). Based on vehicle speed and current it would be a very simple function to determine whether or not to illuminate the brake lights.