Jul 08, 2023

With an EV, can I use one

The 2018 BMW M5 boasts 600 horsepower and 553 lb-ft of peak torque. Acceleration is 0-100 km/h in 3.4 seconds.Jason Tchir

A lot of EV reviews talk about regenerative braking and one-pedal driving. Is this something you can turn off or adjust? Is it something you can use all the time? Are there driving situations where you shouldn’t use it? I’m wondering about whether it works on the highway. – Chris, Toronto

While regenerative braking makes sense in most driving situations, when you’re driving on the highway, consider dialling it down, one expert said.

“I avoid using a high level of regenerative braking on the highway, since you can end up losing more momentum from small [brake] adjustments than you gain back,” said Michael Stanyer, communications program lead for Plug In BC, a Vancouver-based not-for-profit EV education program. “It can also be jarring to exit cruise control right into maximum regenerative braking.”

Let’s back up a little. Regenerative braking recharges the battery as you slow down. It uses resistance from the car’s electric motor to slow the vehicle while converting momentum to electricity, Stanyer said.

In other words, it uses your car as a turbine to generate electricity, which it sends back to the battery.

With regenerative braking, you’ll gain a bit of range when you ease off the gas; you’ll also gain range if you apply the brakes to slow down. How much range can you get back? It varies. But it all adds up.

On many EVs, you can adjust the level of regenerative braking, a setting typically abbreviated to “regen.”

Depending on the level, you may be able to slow down to almost a complete stop just by lifting your foot off the accelerator pedal.

On some cars, you can come to a complete stop without using the brakes. That’s called one-pedal driving and it’s a setting you can turn off, Stanyer said.

At highway speeds with regen set to maximum and one-pedal driving on, just lifting your foot slightly off the gas can slow the car down. While that gives you back a little range, you can lose momentum and have to hit the accelerator again, Stanyer said.

“I use auto or adaptive cruise control on road trips [with regen set to low and let the vehicle sort it out,” Stanyer said. “[However], if you are descending a big hill, dial up the braking regen to control your speed, save your brakes, and recover a bit of power.”

This summer, I discovered how abrupt maximum regenerative braking can be at high speeds when I drove about 300 kilometres – 600 kilometres return – from Munich, Germany to Karlovy Vary, in the Czech Republic. I made the first leg of the journey in a BMW i7 and returned in a BMW iX M60, mostly on sections of the autobahn without a speed limit.

I’d switched on one-pedal driving in both cars. But in the iX M60, the regen was set to maximum through a menu on the infotainment screen and I couldn’t change it back while driving.

I didn’t notice a significant loss in range on either trip – even though I’d set the cruise control to 150 kilometres an hour and I had the air conditioning on the whole time. In fact, both there and back, I got better range than advertised.

In the iX M60, for instance, I started with 417 kilometres and ended with 169 kilometres, using about 264 kilometres of range on a nearly 300-kilometre drive. That was thanks to regenerative braking.

But in busy traffic on the way back I turned off the iX’s one-pedal driving while using the adaptive cruise control because every time the iX closed in on a car in front of me, it would would suddenly slow. It felt like it was slamming on the brakes.

Even if you don’t use one-pedal driving and have regenerative braking set to “off,” your car will still gain a bit of range as you slow down – just not as much, Stanyer said.

Also, be aware that if you are using one-pedal driving, it may not bring you to a complete stop as quickly as the brakes.

That’s why you shouldn’t rely on it for emergency braking. If the car in front of you suddenly stops, always use your conventional brake pedal instead, Stanyer said.

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