[NG_EV]

I was listening to an EV podcast when the host mentioned that the VW ID.4 will have no regeneration on taking the foot off the accelerator pedal in the normal driving mode and it will only coast (in most of the cases). Regeneration will occur only when the brake pedal is pressed. In order to enable the regeneration (on taking the foot off the accelerator pedal), the driver needs to select a different driving mode.
VW states the reason for this is that it makes the drive more predictable.

I do not own an EV and I have no hands-on experience with them. Please give your views on the following questions.

The host mentions in the podcast that the activation of the regenerative braking sometimes makes the passengers in the car sea-sick. Is that so?
Another question I have in my mind is do the current EV owners use 0 regenerative setting and prefer to use the brake pedal only? If so, how does it change your range?


Link to both the podcast and the website from which the podcast sourced its news are here.

Podcast - https://www.evnewsdaily.com/2021/01/...re-holding-up/
(Jump to the 9 minute mark for this story)

Article - https://www.greencarreports.com/news...about-coasting

[mohanphadnis]

compulsory regen is quite irritating.
You need to give continuous accelerator input to maintain the speed.
Plus that regen is just not enough to stop the car completely and in time.

Porsche took this same path with Taycan, where they do not kick in the regen when you take your foot off the accelerator, but applies max regen when the brakes are pressed. (I believe they can recoup as much as 265kW, which means unless there is panic braking, the friction brakes never kick in)

Personally I love what Hyundai has done with kona, and the regen control using paddle shifters gives the driver so much more control. So you can coast on highways, while getting that nice smooth braking using regen when it is really required. I have not tried the ZS's KERS buttons to know how easy it is to work the regen settings, but again, most of the proper EV manufacturers do give option to turn off regen on highways, and that is not only for efficiency, but also because the lift off regen gets irritating.

[speedmiester]

Originally Posted by NG_EV

I do not own an EV and I have no hands-on experience with them. Please give your views on the following questions.

This is very useful and good that VW is providing this option to the driver instead of a default setting.

In Nexon EV, regen is set by default and it is impossible to coast. As soon as you lift your foot off the accelerator, the car starts losing speed as if mild braking is applied. While it's good for regen, it is very intrusive and spoils the fun.

The other two major EVs, MG ZS and Hyundai Kona both offer option to choose the regen setting and it is useful in controlling the degree of regen.

[GTO]

I am a huge "engine braking" guy and hence, love the regeneration feature of EVs that feels very much like engine-braking in ICE cars. Some EVs have it so strong that you don't need to touch the brake pedal for normal commuting (except to come to a stop).

Many EVs offer adjustable levels of regeneration which IMHO is the preferred way.

OEMs shouldn't entirely discard regenerative braking. They should give the driver the option to turn it on / off, and further set the regen level between light / medium / heavy.

[srini1785]

Totally understandable. When a EV is coasting, the motor invariably produces current and the mere flow of current creates a braking effect and the car looses its momentum. Spoils the whole fun of maintaining a steady state of motion especially if you have migrated from ICE to EV's.

However, its a bit mind boggling to think that regen brakes would eventually replace conventional brakes. Sudden applications are not possible with regen brakes as they are "Non contact". Then again, with modern electronics inside, its no big thing to just toggle between two states and make the conventional brakes available at a fraction of a second. So bring it on.

[saikarthik]

Originally Posted by srini1785

Then again, with modern electronics inside, its no big thing to just toggle between two states and make the conventional brakes available at a fraction of a second. So bring it on.

Originally Posted by GTO

OEMs shouldn't entirely discard regenerative braking. They should give the driver the option to turn it on / off, and further set the regen level between light / medium / heavy.

It is a good topic to debate on and also very complex behind the scenes than what an user can understand.

When we talk about regen, there are 2 aspects -

1. How much energy we can recuperate : Increase in range
2. What is the driver comfort levels in the deceleration: to reduce discomfort in hard deceleration.

When we see mostly regen as a separate function and sometimes use engine braking to analogy(rightly so), there is a fine line between the driver comfort and max recoverable energy. This is not just decided by the motor controller, but also by the ESP control unit. The function in automotive industry called as "Co-operative regen/braking". They split regeneration into 2 steps: foot off the accelerator pedal (a.k.a Pedal take off), and brake pedal input. There are some deceleration limits on removing foot from accelerator pedal like 0.12g to 0.18g where the regen works, anything beyond this the driver will feel discomfort. There are very few vehicles with even 0.24g, which purely focus on range due to lower price.

In most of the vehicles regen actually starts while taking off the foot from accelerator (mild regen) and they start heavy regen once brake pedal is pressed. The brake pressure is modulated or delayed till this regen thresholds are reached. This is how one can extract maximum energy without causing discomfort to driver. But it requires higher level of processing power and also there are issues when the electric vacuum pump fails and the braking is delayed due to regen. This is a hot debate even in automotive industry.

[SKC-auto]

Bjorn Nyland had a video just last week comparing the Nissan leaf's efficiency in D mode and B Mode. According to him we can achieve similar efficiency in both modes.

So for EVs where Regen cannot be turned off like in Nexon EV we need to press the throttle slightly to avoid Regen kicking in, agreed it's better to disable but there is a way to coast.

https://youtu.be/equ1wPjeETU

[Ford_Prefect]

I can see why VW is not giving a separate option to the driver for regenerative braking. As EV companies start to expand their EV portfolios, they want to make the driving experience of an EV as close to driving an ICE vehicle. Which means, among other things, an acceleration and deceleration profile similar to a mass market ICE vehicle.

My Niro EV has a 201hp motor and three driving modes for acceleration. The staidest one - ECO - accelerates close to how a gasoline engine does. On the deceleration front, the Niro has regen built into the brake pedal. Additionally there are four regen modes - 0 through 3. Zero means no regen and the vehicle coasts when you let your foot off the "gas". Three gives full regen independent of your braking profile. Then there is the auto version of regen that you can set from 0 to 3. Here the vehicles brakes/regens based on the traffic around you. If you have a vehicle suddenly slow down in front of you, it will apply full regen braking without you touching the brake pedal. This is independent of intelligent cruise control.

I don't know about car sickness with regen. I guess if one accelerates and decelerates heavily, the passengers might experience the same effect. I usually keep my regen setting mid-way in low traffic and highway speeds as I don't like decelerating hard when I am driving at 120kph. In heavier traffic, when I am driving at say 50kph, I keep it on max. The more the regen, the more the energy recovered so range typically increases with regen use. When I press the brake pedal in my vehicle, the regen kicks in first and depending on how hard I am pushing on the brake pedal, the brake pads make contact with the brake discs. I am not sure at what point in the braking process does the manual brakes come on though.

Finally, to srini1785's comment. I do not think we will have 100% regen replacing mechanical braking. They will have to work with each other. This is to do with the how regen braking works. At higher speeds, we generate more electricity and more braking action. To effectively brake this electricity needs to be stored in the battery or "burnt" away and there is a limit to how fast we can get rid of this excess electricity, either by charging the battery or storing in a "braking capacitor". At lower speeds, the electricity generated from regen falls rapidly, so if you need to regen brake to a stand-still at low speeds, you will need a very large motor/generator to convert the low kinetic energy to electricity. So, the need to have a manual braking option is greater a low speeds. Also, we do need redundancy in braking to safely bring the vehicle to a halt so depending on only regen braking to completely stop may not be wise.

[Turbanator]

It takes a couple of hours to get used to regenerative braking on a Tesla. There used to be an option to switch it off before but it appears, it’s discontinued.

When I drove my son’s Tesla for the first time, it felt different but I got used to very quickly. In fact, it works well in snowy weather over regular brakes. And on Tesla, you don’t need to keep pressing accelerator pedal as most of the time it’s in auto mode.

I think, due to lack of autonomous driving, other manufacturers have to go the traditional way.

[carthick1000]

Originally Posted by NG_EV

The host mentions in the podcast that the activation of the regenerative braking sometimes makes the passengers in the car sea-sick. Is that so?
Another question I have in my mind is do the current EV owners use 0 regenerative setting and prefer to use the brake pedal only? If so, how does it change your range?

My current car is a Tesla model 3 (for about 1.5 years now) and in the past I have had a Hyundai ioniq EV and BMW i3 for few months.

I have never felt any sea-sickness in any of the cars. It feels like normal engine braking in an ICE car,except every manufacturer does things differently.
* BMW i3 uses a constant regeneration
* Tesla used to have a 'Standard' and 'Low' setting for regenerative braking, but not anymore
* Hyundai Ioniq has paddle shifters to adjust regeneration in steps

In all these cars, I always used maximum regeneration, as it is more comfortable because you never have to lift your right foot for just casual slowing down. If you predict and drive, even you can come to a complete standstill without even pressing the brake pedal. One will get used to it. Just like every car is different, the regeneration too is. Someone made a nice video of how it works in real life.

https://www.youtube.com/watch?v=JXJPf7Lv8Sw

I don't think that makes much of a difference in the total range, unless you are driving your whole route downhill. If one uses lesser regeneration and more braking, then it only increases the brake wear to an extent. But I don't think it is day and night, because most EVs have some level of regeneration even at the lowest setting.

[mmxylorider]

The Prius has a brake-pedal-press driven regen system in normal mode which is quite good for coasting and on level roads even sustain speed using battery power. The B option which is similar to lower gear on MT vehicles brings in regen braking on easing the throttle. While the objective is to bring in engine braking, this method charges the battery first before moving on to full fledged engine braking.

[AjayJoshuaN]

I think regen should be intelligent. It should not be used to imitate ICE. For example, regen should kick in when going down a hill, or when actually braking for a longer period.

If regen is used as standard(unintelligently), I think it will
1. Reduce the useful distance travelled by the vehicle because it destroys the useful momentum that was generated during acceleration
2. It will mimic frequent plugging in and plugging out of the battery charger, which the battery will not like
3. It will make people press more on the accelerator, because in order to regain the speed lost by regen, again the accelerator will need to be depressed, so the driving style will be more inefficient
4. It will deplete more charge from the battery, because the energy used by the motor from the battery, cannot be regained by the same amount of regen braking

Even in ICE, I think VW had the free-wheel option to increase fuel efficiency by removing engine braking during coasting.

I think the theoretical information and pictorial representations on the dashboard regarding the power gained during regen / fuel saved during coasting might be misleading, because that does not take into consideration the reduction of the capable distance the vehicle can travel without regen.

Let me know your thoughts on this.

[carthick1000]

Originally Posted by carthick1000

* Tesla used to have a 'Standard' and 'Low' setting for regenerative braking, but not anymore

An update/correction from my side. I recently checked this setting and the LOW <-> STANDARD regeneration level selection toggle is/was available again. Looks like this came to exist in one of the recent software updates. How recent? I am not sure. Normally I don't mind checking/changing these Drive settings page often. However, the recent snowstorms and slippery road conditions in NL warranted for a softer acceleration profile. While setting to CHILL mode, saw that the regen toggle is present. The power of software updates always puts a smile in you face

[AjayJoshuaN]

For EV's that don't give us options to control regen, it is possible to switch from D mode to N mode to simulate zero regen, and then back again from N mode to D mode while the car is moving?

[StarrySky]

While the ID..4 basically coasts in the D mode most of the time, the regen can kick in when needed. The navigation system knows when the car is approaching a round-about or lower speed limit and can prompt the driver to take the foot off the A-pedal. Then the car slows down via regen. This does not require navigation (I mean no need to plan a route) or adaptive cruise control to be turned on.

This video explains the system:

https://www.youtube.com/watch?v=a9w22O0Rvgk