For a while now I've been getting ready to describe what regenerative braking and One Pedal Driving (OPD) actually are.
Regenerative braking is nothing more than recovering energy while braking, which can then be used to charge the battery. It's nothing new – most hybrids have it, and some non-hybrid cars do too (they use it to top up the 12V battery).
In the current version of Tesla's software you can't adjust the strength of regenerative braking, but it works pretty well. We can bring the car to a complete stop without touching the brake. And that's exactly the magic of One Pedal Driving – controlling the accelerator pedal in such a way that you use regen to brake while recovering energy at the same time.
Is it simple? Yes, but not entirely. Is it easy to get used to? Very easy.
Why is it simple, but not entirely? In the city, after one or two braking manoeuvres you more or less know what to do. On an expressway (speeds of 80 km/h and up), easing off the accelerator slightly can cause braking and, more importantly, turn on the brake lights. There's a regulation for this (probably from the EU) that defines at what level of deceleration a car has to switch on its brake lights. That can confuse the driver behind us. What's more, slowing down too sharply may force you to accelerate again, and accelerating uses more energy than we recover while braking. Savings turn into extra costs. That's why OPD outside the city takes a bit of practice. The S3XY Dashboard app helps me a lot with this, and I'll come back to it in a separate post. The dashboard itself, connected to the Commander, displays all the key information that makes learning OPD easier:
- energy use by the front and rear motor (a negative value means energy is being recovered),
- a scale showing whether energy is being recovered or used at any given moment,
- information on whether the brake lights are currently on,
- speed and other driving parameters.
All in all, you can find a position of the accelerator pedal where, on level ground at around 50 km/h, you use about 2 kW of power (my best result is holding that level of consumption for about 2.5 km without stopping in the city). On the motorway at around 150 km/h I manage to keep power use at 25 kW, which translates to about 17 kWh/100 km on a flat road.
I'm still training and learning how to use OPD optimally. I think mastering this technique is the key to achieving low energy consumption while driving.
I'm not updating the driving data after this post, because since the last post the Tesla hasn't left the garage :)