Electric car on the smooth

A woman experienced several times that the Tesla lost traction on winter roads. It slid into the wrong lane. Elbil24.no wrote about this earlier. NAF warns drivers of electric cars against regenerative braking on winter roads. Is driving with one pedal unsuitable for smooth winter roads?

Are electric cars more dangerous than other cars on the road?

The incidents occurred in a Tesla Model Y, but can certainly be provoked in other electric cars with regenerative braking. The woman who experienced slipping into the opposite lane said the following:

"Out of habit, I let off the gas on the way into a bend, and find that the car brakes sharply, then slides into the opposite lane."

When the BMW i3 came with a one-pedal solution, I imagined that this could happen. I drove up to Sørkedalen to test how one-pedal worked over a parking lot with mirror-like ice on a slope. I hit the gas, aimed diagonally across the icy section and let off the gas abruptly. If you release the accelerator suddenly, the car brakes more strongly than if you release it slowly. Since the BMW is rear-wheel drive, I expected the rear wheels to lock and the rear end to drag down the slope in the same way as when you grab the handbrake. But nothing happened. The car did not brake as usual. I assumed the ABS system was preventing the brakes from taking effect. On the way back I had to speed up to get over the icy place - it was so slippery. I tested several times, and "cleared" the BMW i3 for the same thing that the woman with the Tesla Y reported.

Left to the car manufacturers

Both the BMW i3 and Tesla drive with a so-called e-pedal, where the drive wheels decelerate as soon as you lift the accelerator. During normal driving, the 4-wheel drive Tesla "Dual Motor" primarily pulls on the rear wheels. Locking the rear wheels against a bend can throw the car off course on slippery roads. The problem with cars like the BMW i3 and Tesla is that we can't switch off the one-pedal driving. We have to trust that they don't lock the wheels unwanted. Tesla reports that they have made several improvements to their software.
 
The Tesla Model 3 automatically goes into a kind of snow mode when it detects winter conditions. Bjørn Nyland (Tesla Bear) discovered this during their measurements and have documented it on their YouTube channel. This is good news, but still a puzzle as one wonders if the technicians in California manage to imagine Norwegian winter roads at their worst. Furthermore, I hope that they are careful when they "tamper" with the winter driving characteristics, so that the cars do not change character after a program update.

How should one prepare for wheel locking with regenerative braking?

Although regenerative braking should never lock the wheels, one should be prepared for it. On the Tesla Model 3 of 2020 model or older, you can choose to drive with "Chill" throttle application and "Low" regenerative braking. It works well in winter. On later models, regenerative braking can no longer be set. Since the system is not perfect, it is required that you get used to driving safely with one pedal. At the driving school, we have learned to handle difficult situations by pressing in the clutch and letting the wheels roll freely. You can't do that on an electric car. To let the car roll, you have to keep your foot on the gas so that you neither accelerate nor brake - between consumption and charging. On smooth surfaces, you should gently lift the accelerator to brake carefully. It takes a mental adjustment not to "jump off" the gas when things get scary.

Favorable weight distribution

Electric cars and hybrid cars with a centrally located battery pack have a more favorable weight distribution than most fossil fuel cars - close to 50/50. I have studied the weight distribution on the most popular models, and they show that cars that pull primarily on the rear wheels have slightly more weight bak, while front-wheel drive cars have more weight at the front. This is absolutely ideal and a great advantage in winter driving. Favorable weight distribution means that the consequences of oversteering or understeering are not as dramatic. Weight on the drive wheels also provides better road grip when starting up.

Use the four-wheel drive correctly!

Many electric cars have 4-wheel drive. That's good, but can give false security. The 4-wheel drive helps you when you step on the gas. For many, it is unusual to step on the gas when things get scary. Intuitively, you will then let off the gas and brake. It is therefore important that you arrange your driving in such a way that there is room to give gas in parts where you can easily lose your grip. Take it easy when you drive into curves, around street corners and roundabouts and you will have room to hit the gas to get out. If you enter the roundabout too quickly and are forced to brake, the 4-wheel drive will not help you.

Electronic systems

All modern cars are equipped with "anti-lock" brakes and anti-skid. Some cars also have their own driving programs for winter driving. Electric cars have good driver assistance systems. The best systems already correct oversteer and understeer before the car loses traction - so that it is difficult to provoke it even on purpose. Test the anti-skid system in a safe place, an open space or similar. Find out how much it takes to get the car out of balance and how much the car can skid before the system catches it again. In many cases, enough to be able to cause significant damage should a situation arise.

Are cars without an e-pedal preferable on smooth roads?

The electric cars from the Volkswagen group (Audi, Seat, Skoda, VW) cannot be driven in pure one-pedal mode. They still have a functionality that you should be aware of. If the car has "automatic" regenerative braking, the car's adaptive cruise control and navigation system are used to regulate the braking. If there are no obstacles, the car will roll freely and the brakes will automatically apply when it approaches an obstacle. I have not tested this type of braking in freezing rain and ice, but consider that the system can pose a potential risk of locking the wheels in the same way that Tesla Model Y owners have experienced. If, on the other hand, you set recuperation to "manual", the car rolls with no – or very little – regenerative braking. You can adjust the braking force manually - either with "paddles" on the steering wheel, or via the gear lever. This is a great way to drive an electric car and is unlikely to cause any negative surprises on smooth roads.
 
PSA's electric cars (Citroën, Peugeot, Opel) have manual regenerative braking with paddles on the steering wheel.
 
Volvo's electric cars optionally offer either manually controlled regenerative braking or the option to drive with one pedal.

Conclusion

New cars must not lock the wheels when braking, either with the use of the foot brake or regenerative braking. The technology for "anti-lock" exists, but we cannot rely on it 100%. After all, it's about life. Therefore, we must realize that there is a risk that the car's regenerative braking can take the car off course on extremely slippery roads. NAF's recommendation not to use regenerative braking - or to set it to the lowest strength - is real. If the car can only be driven with one pedal, it is an advantage to familiarize yourself with the car before taking the car straight out on the winter road.

Especially if you get your new Tesla delivered in the middle of winter.

Take it easy – keep your distance – keep a steady flow – use your turn signals – give your brake lights – make room for other cars 🙂

 

See

 

Elbil.24 – The Tesla just slipped into the wrong lane

Tesla Model 3 LR Snow Mode demo and explanation by Bjørn Nyland