Source: Britain’s irreverent Car magazine tested the new Porsche Taycan EV (electric vehicle) to determine how well the regenerative-braking system worked within the car’s overall braking system. The following is excerpted from the article, which can be read in its entirety by clicking on this sentence.
The figures are impressive enough. The Porsche Taycan is a two-ton car capable of 0-62mph in under three seconds, with braking power to match. The front calipers on the Turbo and Turbo S have 10 pistons apiece, with six on the 4S. A big stop in a Taycan feels like galloping into a patio door.
But it’s not only discs and pads doing the stopping, it’s regenerative braking too – e-motors go into reverse to recharge the batteries and shed speed. Despite all the hardware, the algorithms and the blend between regen and regular braking, it’s impressive just how natural the feedback feels.
There are actually three regen modes selectable via a button on the wheel. One feels like normal engine braking, another is regen off, and there’s the camera-based adaptive mode we’re testing.
Unlike other EVs, the Taycan prioritizes coasting over recuperation when you release the throttle. It’s more efficient, says Porsche, and gives the car a more natural feel than the sudden loss of speed we’ve come to associate with battery-powered vehicles – that feeling familiar to Nissan Leaf drivers, as if you’ve lobbed an anchor out of the window every time you take your foot off the accelerator. The Taycan’s adaptive system offers something like normal engine braking in steady-state driving but increasing in severity when the car detects traffic. Like adaptive cruise control, but more subtle and on all the time.
Significantly, Porsche’s Surface Coated Brake discs are standard. They use a layer of drill-bit-tough tungsten carbide to reduce wear and resist corrosion. Porsche reckons 90 per cent of day-to-day braking will be done by the recuperation system, leaving a set of standard iron discs at serious risk of furring up. The service schedule shows the pads need attention – but not necessarily replacing – every six years; that’s how little wear they’ll get.
It’s only possible for those vast, powerful brakes to be the secondary means of slowing down because the regen system is so powerful, even if it feels natural and unintrusive. Up to 265kW can be clawed back at deceleration of 3.8 m/s2. This is a lot, but unlike most regen systems you don’t notice it when you ease off the accelerator, only when you press the brake pedal, and even then it’s hard to tell which system is being used.