Different braking implementations
OK, maybe I am a non-friction-braking junkie.
Today, I had a discussion with a friend who owns a Tesla model S. The single motor type, but with the complete performance pack. As we started to talk about braking, we figured the S’s stategy is quite different than on the Zoe and is actually closer to the Fluence and Kangoo. In simple terms, on the S, touching the braking pedal does friction braking, period. Regeneration is applied through not, or barely touching the accelerator. He calls this “one foot driving”.
He also told me the “average” tesla driver doesn’t do any aiming-braking. With that I mean unpowered coasting, letting the motor basically run free. It seems to be popular with Fluence hyperdrivers to avoid the regen-use cycle. I have to assume this is because hyperdriving is less of an issue with a 80kW battery.
The regenerative braking strategy itself is different too. The Zoe seems to aim at fixed torque, mimicking a traditional car. It is transparent to the driver if that torque is generated through regeneration or friction braking. The S seems to aim at a fixed regeneration power level (up to 60kW, which is lower than the Zoe per kg). As I explained in the previous post, that means increasing torque as the speed bleeds off. When the car reaches roughly 50km/h it seems to switch to constant torque, probably as otherwise the braking would get too brisk and uncomfortable. It is an interesting approach (irrespective to whether it is controlled through a braking pedal or not) as it is the behaviour I am trying to mimic through following the blue bar in the driving screen.