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by EForEndeavour 829 days ago
I've never driven an EV. How do you approach stop signs and red lights other than braking? Is "engine braking" (regenerative braking?) strong enough to handle that big a fraction of slowing down in city traffic?
13 comments

Based on my experience (electric motorbike), the regenerative breaks are super strong indeed. You can tweak their « force », but usually, the strongest level is the most comfortable - that you eventually keep all day long. It will cause you to full stop even on the steepest slopes.

Once you’re used to it, you dose your deceleration by focusing on how much you release the throttle.

And the only situations where you have to hit the breaks are the unexpected events - e.g., a car coming at the last moment and which you should give priority to.

An electric engine running in reverse is a battery charger, so yeah you run it in reverse and you slow down about as fast as you accelerate.

It doesn’t work completely like that obviously for reasons, but it does work like that for gentle accel/decel.

You just let off the accelerator. They have tuneable deceleration curves for the regenerative braking.

Think of it like playing a console game. When you hold the right trigger, your car goes faster. When you let off of it, it naturally slows down. Unless you opt in to harder difficulties, most racing games don’t make you brake much.

Driving an EV is just like that. You only really brake for an immediate stop.

I have a Prius hybrid. It has an indicator when the brake pads are used. It's easy to slow down and stop without using the brakes about 95% of the time
It depends. On new EVs (which formally designed as EV from scratch), motors and charger are usually powerful enough to exceed brakes.

On conversed, usual practice to limit torque of motor to be less than on ICE original, because of regulations (which exactly state, electric motor should not exceed ICE torque), and this mean, they are just not powerful enough for 100% regenerative braking.

From technical view, modern electric engine could easy exceed brakes.

I'm member of Ukrainian EV activists group, and we there mostly talk about conversions. Unfortunately, conversions are not so cool as new EVs, but to be honest I don't know details of other countries regulations, they could be less restrictive.

Some EVs also tie in the same detection devices used for adaptive cruise control to adjust regenerative braking. It can be configured to 'coast' in a manner similar to old-school automatic transmissions, but will apply regen braking when other vehicles are detected ahead. This lets me drive it sort of like a regular automatic when on the highway but get the added return of wattage when traffic gets heavier.

There's also one-pedal operation, akin to driving a golf cart. Where you feather the accelerator pedal to slow, and it will engage much more aggressive regen braking if you let off the accelerator pedal. Some folks like this. I do not. I still drive other ICE vehicles and find the transition between them too jarring for my liking.

In city traffic, I rarely have to break. It's basically running the motor backwards (putting a load on it) and dumping the energy back into the batteries. It's limited by how fast the batteries can accept a change, so it doesn't always work when it's very cold out. I'll have to brake when a light catches me by surprise, and I brake when backing down my steep driveway. (The car does stop before getting into the street, but it's going faster than I'm comfortable with when approaching the sidewalk.)

The regenerative breaking is applied as you let off the "gas" pedal. It's kind of like driving a stick, but slows you down faster.

It’s also limited by the size/power of the EV’s motors. A dual-motor, AWD EV can stop more aggressively using regen than single-motor variants.
From what I know, there are several settings of regenerative braking you can choose. The higher levels will bring the vehicle to a stop, while the lower ones won't. So it's user-configurable to a degree.
Recently had to learn how to force a Prius to use the brakes, as the rotors were rusting up & starting to pit!

I could not get my partner to brake hard enough to really engage the brakes. They just would not do it, would not brake hard enough to actually use the real brakes, no matter the prompting & even knowing how critical it was that we start to de-rust these rotors.

What I found out is: if you put the car in neutral, there won't be regenerative braking, & the car will use the actual brakes. That's the only way I could get my partner to use the actual brakes.

I would have expected cars that have both conventional and regenerative brakes to keep track of how often the conventional brakes are being used and to automatically increase the use of the conventional brakes if they aren't being used enough to keep them in good shape.

Are there any that work that way?

The polestar 2 does the simpler thing of biasing towards mechanical brakes for a little while at the start of every trip. (I suspect this has the advantage of detecting brake failure in more controlled circumstances as well, but that's not specifically documented.)
I'm sometimes convinced Tesla's cameras identifies the stop line and stops itself exactly there. All I do is release the throttle pedal and it coasts there where it needs to be.
The engine can slow down the vehicle at roughly the same rate it can accelerate it. And if you have an EV that has a 3 second 0-60...
Generally, yes. Usually there are settings for how much regen you want, but the term 1 pedal usually inies a regenerative brake strong enough to stop at stop signs or when exiting freeways.
"1 pedal" just refers to vehicles that perform a high degree of regen when the throttle is lifted. Other designs that require the user to press the brake pedal are not necessarily engaging the brake pads when you do so, many of them are also slowing the vehicle with regen when you press the brake pedal.

When you press the brakes on an EVs or hybrid, they typically use regenerative braking up to the limits of the motor and charging system, and only apply the brake pads after those technical limits are met. There are many "two pedal" vehicles that can come to a complete stop, or close to it, with regen.

It's a timing skill you rapidly develop. Switching models throws off your timing, so don't be surprised when you initially use the brakes more.