Regenerative braking optimal level

Had the e-Niro 4 for a few weeks (amazing car!). Interested to know if anyone has a sense of which regen level is best for maximising efficiency and range? I assumed setting it to the highest level (3) would return the most miles as you capture more when slowing down but reading the experience...

www.speakev.com

There has been a lot of discussion on similar topics, so try the search function. I find the graph from the link, very useful.

 

There's no right answer, just what suits you best. Obviously using regen is more efficient than using the friction brakes, but using brakes unnecessarily is less efficient than only using them when you need to.
Generally the higher degree of regen selected the harder it is to avoid unnecessarily having it engage either resulting in a less smooth drive or unnecessary amounts of braking. Because of the round trip losses from kinetic energy to electrical energy to chemical energy and back again being of the order of 20-30% it is better to keep kinetic energy than try to store it via regeneration for later, for example when going down hill if it's safe and legal to do so it's better to let the car speed up and then coast back to the desired speed than use regen to keep it at a constant speed and then use the energy regenerated to maintain speed later.
There's only so much throttle movement and the more regen selected the coarser the change in drive/regen for a given amount of throttle movement. If you are good at controlling this you can largely avoid using the friction brakes and save energy, but the danger is you'll have a jerky progress and waste energy.
The brake pedal is just as good and efficient way of controlling the car. But single pedal control sells, with manufacturers championing things like e-pedal.

 

There's an error in this analysis. Going down hill, one is losing potential energy not kinetic. Allowing a vehicle to speed up going down hill will just result In energy loss via wind resistance quite apart from risk of loss of control. So best on a downhill section, to use regen to maintain speed!

 

My personal preference is regen level 3 (max) for town driving. Gives me almost one pedal driving and I’ve got well practiced at feathering the pedal.

This approach doesn’t suit everyone. My wife prefers level 1/auto. I personally don’t like auto as I prefer the car’s behaviour to be consistent. Auto increases the regen if the radar detects the vehicle in front is slowing.

I never stop by holding the paddle, seems a total waste of time as it actually uses energy to hold the car. Do as much of the slowing down with regen and use the brake pedal to come to a stop.

Regen is clearly preferred as the primary way of reducing speed, it captures energy rather throwing it away as heat. It isn’t 100% efficient so any loss of momentum has an overall efficiency penalty but we all have to slow down at times. Gently pressing the brake pedal does trigger regen but also involves the friction brakes.

As for avoiding wear on the friction brakes, a common issue on cars with regen braking, since the first Prius, is discs and pads having to be replaced prematurely due to corrosion because they don’t get enough use, so this is a balance.

 

Gently pressing the brake pedal does trigger regen but also involves the friction brakes.

No it doesn't. It uses the friction brakes to come to a complete stop. For just reducing speed, only regen is used.

 

Thanks everyone for your input, very useful, and thanks @Todor for the link, that covers much of what I was asking.

 

I was in the drive mode settings screen yesterday adjusting the regen levels for the different modes. I noticed that the efficiency of the regen was displayed was between about 75-85% 1-3 if I remember rightly.
My preference is 0 regen and Auto but often forget for a while after driving.
I don't use the paddles very often just to set the level, may use a bit of more regen if I am catching up a car faster than I'd like or going downhill where car is speeding up enough to break speed limit.
I find using the brake pedal a much smoother experience and more control. It gives more the than the set 2, 4 and six bars regen without the transition jerk.
AFAIK the friction brakes are still not used until the 5mph, you hear them start grinding, unless the car thinks they are required. I don't think smooth gentle braking triggers them until the last minute.
I don't like pulling the left paddle as a viable means to come to a stop, unless it is that last moment where the car is just about to stop, just as easy to use brake and autohold, it is too harsh for braking and getting the timing right is too difficult to judge leading to jerky driving something my partner does not appreciate due to travel sickness. It's the stopping speeding up motion that gets her. I think there has been a lot of people complain about travel sickness in EVs for this reason and the fact the is no change in engine noise to detect when it is happening.
Posing questions
Is the selling of 1 pedal driving Nissan's equivalent marketing to Toyota's self charging hybrid rubbish due to the lack of control over regen, effectively strong or weak regen.
I wonder how many times 1 pedal drivers actually still use the the brake because of a wrong assesment of the conditions in front.
I do think one pedal in stop start traffic is good. SCC does this for you with little or no input from you, a tap of the pedal or cruise control switch to get you moving again.

 

I think people place too much emphasis on regen because it's new so it must be better, yeah? I do like it in slow town driving because it is very easy driving. But as soon as I hit open road, I turn it down to 0.

I have never bothered to try doing comparisons but more dedicated people than me suggest it is more efficient to coast as much as possible and then use the foot brake because it regens anyway until you press hard enough for it to realise you need more help and then it uses the friction brakes. I have no reason to doubt or contradict them. When turning it down you can feel it freeing up. With regen set high, I liken it to the feeling you'd get if your friction brakes were jamming on - you feel like you need more power to overcome the constant urge of the car to slow down. Not in any way a scientific analysis but there you go.

 

I think people place too much emphasis on regen because it's new so it must be better, yeah? I do like it in slow town driving because it is very easy driving. But as soon as I hit open road, I turn it down to 0.

With regen set high, I liken it to the feeling you'd get if your friction brakes were jamming on - you feel like you need more power to overcome the constant urge of the car to slow down. Not in any way a scientific analysis but there you go.

ive noticed the same.I drive in town on 1 and if I remember, on motorways on 0 and when you do that the car almost seems to jump forward, but I've also got over the urge to marshall every spare electron, with 250 plus miles range it's rarely if ever a concern.

 

I know what you are saying the the motor is being restricted or released when changing regen levels.
When changing from normal to eco default L1 to L2 it feels like you have put the brakes on. It is not that the motor is being restricted in that regen mode that would be counter intuitive to make the motor to work harder for the same speed.
The feeling comes from the different mapped positions for the accelerator pedal. The same position for eco would be a slower speed than in normal so it gets to slow down and visa versa for eco to normal, so it's just the motor compensating for the different mapped positions of the pedal if the car is in motion. That's my theory.

 

Well we all try to understand new things and that is good. If you want to be efficient, that is fine. If you want to enjoy your car, drive it the way you enjoy!

I think the Soul has one of the most customisable driving experiences available. Someone in another thread pointed out the various combinations: drive modes x 3, regen level x 4, Auto regen, Auto Hold.

That is an amazing range from basically "full pedal control" to almost "1-pedal" driving.

 

Just a shame, in my view, that it has such a wide range of options but doesn’t offer the thing that many drivers (once they have it) really do seem to like - ie. regen to a full stop.

 

The i3 I had before did not have any customization, it just regened hard to a stand if you lifted the accelerator. It was true one pedal driving. I just wished there had been an option to turn it off as it was a pain to drive on a motorway as you had to balance the accelerator pedal.
I think that is all that is needed, the Soul has too many options and levels and all it does is add confusion.
I also wish that the Soul would come to a stand without pressing the brake pedal as the i3 did, it still catches me out sometimes. [emoji33]

 

I noticed this in the Soul EV brochure. It seems to suggest there is an option to select single pedal driving or use the left paddle to come to a stop. Is this the case or is the information incorrect?

 

it's not either/or - the soul doesn't have pure one pedal driving in that whatever the regen setting it doesn't come to a halt if you take your foot off the accelerator. (unless you're going uphill!)

However you can hold the left pedal at any time to bring the vehicle to a halt - it only uses regen braking so its never hard braking - there were occasions when I found myself pulling quite hard on the paddle - which is silly as the regen braking is not paddle pressure sensitive.

My driving is mainly urban - I've evolved to using auto hold and level 3 regen with the paddle to manage the final stop at most lights/junctions - this has the plus that it doesn't leave the brake lights on when you've stopped and you don't get the tiny pause/jerk when you move away as auto brakes come off - but obviously it's no sweat to dab the brake pedal to get the "handbrake" on if you need it. That combination suits my driving style and rarely use the brake pedal in normal driving.

I do switch auto hold off for manoeuvering - it's too limiting when reversing into/moving out of a parking space

 

it's not either/or - the soul doesn't have pure one pedal driving in that whatever the regen setting it doesn't come to a halt if you take your foot off the accelerator. (unless you're going uphill!)

Are you perhaps referring to the "First Edition" MY 20 Soul EV? I think the difference between your answer and that given in the brochure (that the regen system can bring the car to a halt without the use of the brake pedal) is that the brochure relates to the MY 22 Soul Maxx. .