Regenerative Braking

I am going by my experience and knowledge of driving - the kinetic energy of the moving vehicle is best used to keep moving the vehicle forward. Regen is fine for when you actually need to slow down - it is infinitely better than heating up the friction brakes. But, it cannot regain as much energy as you use during coasting, so if you can coast down some and then use regen at the end, that is better.

The main point is - it is not either / or coasting / regen. It is whether or not you can easily coast each and every time. Coasting is part of traveling - and regen is only generally part of stopping; or when you have a steep downhill.

 

No when my KONA is coasting its often using regen and putting it back into the battery.
Your coasting method in the Kona would not be super efficient with lack of regen imo.
For what i would save is not worth getting yelled at, ppl passing me, driving at slow speeds and slowly coasting to a red light and disrupting traffic flow.

 

The physics and electric power conversion technologies present in an EV back up the view that minimising regen is more economical, just like minimising braking is the same on an ICE car, except not nearly as bad in the EV. Regen in an EV will lose you about 30% (my guess) of the kinetic energy you are attempting to recover while an ICE loses 100%. The reason to prefer level 0 as a setting is only that the accelerator pedal is less sensitive to inadvertent regen, "rubber band" driving in other words.
But when you have to slow down quicker than level 0 coasting, the difference between "regening" with the paddle level setting 1-3, left paddle hold, or applying the foot brake is minimal, as they all return roughly 70% of kinetic energy to the battery, with the the foot pedal using friction brakes only when nearly stopped.

 

Coasting means you're not putting energy into the motors and you're not regenerating. If you come to a stop in front of a red light, it doesn't (or does it?) matter if you're coasting and then regenerating hard, or regenerating less over a longer period.

That is actually something I would like to find out. What recuperates more energy from the same speed? A short and hard regeneration or a longer softer regeneration?

I feel what you guys are divided over is more a forward looking driving style than regenerating.

It is totally possible to coast in a regen setting of 1,2 and 3. It's just about being able to find that sweet spot with your foot.

I personally like having Regen 2 in City driving and regen 1 on highway driving because it allows me to slow down without changing the setting using the steering wheel paddles all the time. It's just more relaxed driving for me if I don't have to adjust settings all the time. I personally think I'm good at coasting with Regen active and if I have to stretch my foot I can still set regen to 0 and take my foot of the pedal.

An ev coasts so much better than an ice car anyways because of usually higher weight and no gear drag.

The reason for having to slow down is mostly other drivers and not myself not driving with a good enough foresight.

Sent from my moto x4 using Tapatalk

 

You haven't convinced me that you're doing anything different other than not feathering the accelerator, which is no great advantage. I'm sure most of us regen fans instinctively coast at opportune times by bringing the power gauge to neutral with the pedal. (It bears repeating that pressing the pedal does not necessarily mean applying power.)

 

It is better to go lighter for a longer period of time (when you need to stop, or slow down on a long downhill). Battery cells have a limit, and spreading it out over time adds up to more Ah.

There is a 0 setting on the Kona Electric, right?

 

When you're feathering the accelerator, you're bound to not coast very consistently. Again, coasting is serving a very different purpose - you want to continue driving. Regen is for slowing down - would you tap the brakes as you drive? In the e-Golf (and I assume the Ioniq Electric, and the Kona EV in 0 mode), you can feather the accelerator, but there is no chance of "tapping the brakes". And being able to lift your foot - if only to stretch out your leg - and coast consistently, means that you are not wasting effort and not losing energy in the regen process, again and again and again over a long drive.

At the end of a long drive, or at any point, you can MODULATE the amount of regen you need, by momentarily pressing the brake pedal.

Heavy regen on the accelerator i.e. 1-pedal driving, is okay in heavy stop and go traffic, where you need to be brisk. But, it is kinda' like racing - accelerate / brake. And if you watch Formula E, you see this uses more energy. During much of the race, they accelerate, then lift and coast, then use regen.

 

Yeah, driving style is an individual choice ... we can only try to agree on the technical characteristics of the Kona.

Regen can be 119 kW from 100 kph (my measurement off the dash) and obviously tapers off at lower speeds. A "1C" charging rate is 77 kW as a reference (64 kWh battery), so that regen charging is high but intermittent. No doubt higher charge currents cause higher resistive losses in the battery but I think that's a secondary issue and not worth worrying about in the context of this conversation. Just think of it as the same regarding low v.s. high regen in terms of getting back that energy from any given speed to any lower speed.

I actually don't care too much about efficiency in daily driving but the question of regen level setting v.s. economy can theoretically boil down to how carefully you can modulate the accelerator pedal about the zero regen coasting point. I can't and like to relax my foot frequently so level zero is my best option for economy, certainly not for convenience in traffic, as pointed out.

 

Heh, so traffic flow wants to me *accelerate* towards the red light before I brake for the red light?

My feeling when I drive (especially in the city and suburbs) is that if I'm on approach to a red light that will still be red when I get there, it doesn't matter how slow I'm going. I should go as slow as I need to, with the goal of arriving at a green light. I rarely notice anyone mad at me at all, although I have to be aware of people wanting to arrive at the red light quickly so they can make a right turn. I generally change lanes so as not to be in their way.

Occasionally someone does slow down behind me, then pull around me in a huff, then arrive almost immediately at the red light. I'll pull up next to them and shrug, then point at the light. "We're both here at the red light! But you beat me to it. Congratulations!"

 

Every traffic study shows that smooth and steady flow is much better.

 

Based on the way these systems are designed, both chemically and electromechanically, it's always going to be better to regenerate more gently rather than carry speed for a while and then regenerate quickly. System suffers less breaking torque and the battery will experience less charge current and lose less as heat.

This assumes you are definitely going to stop (e.g. a stop sign) but at a red light, NeilBlanchard would point out that if you time your coasting/decelerating correctly, you are going to be arriving at green light, and you [key here--->] won't stop. Kinetic energy is a kind of battery too, and it's very efficient to get energy into and out of!

Every m/s^2 that I don't decelerate is a m/s^2 that I won't have to accelerate.

 

I, too, wonder what the gang means by "coasting," Could be several things. But Lordy!Lordy!, I hope it doesn't mean driving in neutral.

 

I'm sure you got more than you bargained for.

You can coast in neutral, but you can achieve the same thing by setting regen to zero, or by applying just enough accelerator to offset regen. Whenever the power/regen gauge shows no bars, you are coasting or close to it.

 

If it is regenerating power back into the battery - that is not coasting.

 

In an ICE vehicle shifting into neutral will disconnect the engine from the driveshaft, works better to coast but is also very very illegal and dangerous. An electric vehicles neutral is just a peer disconnect as the motor and wheels are permanently connected.

 

Coasting can only happen if there is no regen on the accelerator pedal - and yes it happens best when you lift your foot off the pedals. On some EVs, you can coast in D - this is preferable. But many EVs need to be put in neutral in order to coast. This is not ideal, as you lose regen on the brake, and you have to put it back in D in order to accelerate.

 

Again, simply not true, and all your expertise in EVs does not make you a Kona owner. You've argued that setting regen to zero is a more surefire way of coasting than feathering the accelerator, but apart from that, there is no difference between the two methods. If neither power nor regen is being applied, it's coasting.

 

Well, with the Kona, as SP mentioned above, you can easily get into "coast" mode by just controlling the pedal, and the gauge tells you that, too. That's why I drive in ECO most of the time. It lets me coast or regen brake as desired and with traffic,... without annoying other drivers.

If people are really interested in getting the most efficiency out of your driving, I think there is more payback in how you control your acceleration. I know when my son first got his Tesla, he loved to demo his power to me, but also showed me how it immediately knocked off many kms on his range. I am not suggesting babying your pedal to achieve ultimate efficiency. That would be just as annoying to other drivers as coasting. But just don't tromp it all the time or too much, when taking off from a red light. Again, best is just try to go with the traffic flow. That is the safest way to drive and no risk of inviting any road rage.