Regenerative Braking

Discussion in 'Hyundai Kona Electric' started by Boston Charger, Jun 16, 2019.

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  1. Boston Charger

    Boston Charger New Member

    OK, so I'm new to the EV scene. I can't find, in all that Hyundai docs that they provide, an overall explanation of when to incorporate the RG system into my daily driving. I'm gathering that it be primarily used during braking. Should I have it set at 1 all the time, and increase to 2, or even 3, during braking? If not braking, does being set at a constant 1, say on the highway, create drag which uses more energy, and offsets an possible gain via regeneration? TYIA!
     
    Domenick likes this.
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  3. Hey, welcome and congrats on your EV!

    The Regen setting is really only whatever you personally like the most. I myself like setting 2 the best for city driving which is most of my driving. I also have auto Regen activated, so it increases automatically to 3 when I stop behind another car at a light.

    For extended highway driving 1 or even 0 might be more comfortable since you can take your foot of the pedal without slowing down much.

    But, it doesn't have any effect on your consumption. You're not trying to overcome any resistance with a higher setting, that is not what happens.

    With a higher setting it only enables you to better one-pedal-drive, to put more energy back into your battery while slowing down in different situations workout using the friction brakes.

    I hope this very generic description helped you get an idea.

    Sent from my moto x4 using Tapatalk
     
    Brennan Raposo likes this.
  4. "Whatever you personally like" is the key here. Regenerative braking is part of how the car slows down by whatever means you select, including the brake pedal, and it will recover most of that kinetic energy whether you like it or not. Economical driving is much the same as it's always been with ICE cars - drive smoothly and avoid high speeds.
     
    Esprit1st likes this.
  5. SkookumPete

    SkookumPete Well-Known Member

    Regen occurs when the motor becomes a generator. The regen setting has no effect when the motor is driving the wheels, other than by remapping the accelerator pedal. Note that you can have a foot on the pedal when recouping. You're not actually applying power, just lessening the regen.
     
    Jared Potter likes this.
  6. I wanted to echo what KiwiME said, ^^ and also point out that most ICE drivers (generalizing from driving experience in several parts of North America) have never thought about whether they could look a little further down the road and brake more gently, while still maintaining their overall speeds. Both incentive and information are missing for most ICE drivers -- but in an EV, the dash gives you the information and the incentive is significant. Many new EV drivers change their driving style to anticipate what's coming up down the road, arranging to arrive at green traffic signals and changing out of congested lanes. Doing this allows the system to capture a lot more energy, because braking beyond a certain threshold will still use the brake pads, losing the kinetic energy to heat instead of recycling it to the battery. If you drive like a Roman taxi driver (no offense!) with either the accelerator or the brake on the floor at all times, you'll use way more energy, have less range, and (in my experience) not get there any sooner.

    The mental effort of anticipating conditions down the road might be noticeable at first, for some drivers, but with a little practice it becomes automatic like other good driving habits.

    This message brought to you by my Dad, who didn't live to see an electric car in the driveway but hated to spend money on extra gas and replacement brake pads. :)
     
    Kitsilano, Jared Potter and Esprit1st like this.
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  8. NeilBlanchard

    NeilBlanchard Active Member

    I would advocate for using no regen on the accelerator, and coasting when possible. This is more efficient use of the kinetic energy of the moving vehicle, and it tends to let you accelerate less. You can go farther per charge when you coast easily and predictably.

    Regen is great for when you need to slow down, and it is much better than the friction brakes. But regen is always going to lose some energy - so if you accelerate hard, and then immediately use heavy regen, you will see significantly higher energy consumption.

    Lighter acceleration, some coasting, and light braking is always going to go farther on a given charge.
     
  9. That to me just describes a person who is a poor driver overall. People who drive with two feet, one on the gas one on the brake so they’re braking up hill etc. If you’ve set your Regen level to 3 and you’re constantly wildly going from accelerating to regenerating it means you have poor foot control and poor control of your vehicle. The Kona EV is more like a multi step e-pedal design, not quite a two pedal & not fully a single pedal system. But if you’re constantly relying on coasting modes to keep a consistent speed so therefore wasting energy by not maintaining flow/ constantly overcoming inertia, this isn’t the cars fault or the modes fault this is entirely a bad drivers fault in wasting energy.
     
  10. Kitsilano

    Kitsilano Active Member

    Strange to say, there seems to be no evidence-based study comparing energy consumption at various regen settings and braking practices. Until that is done, my own practice is to use AutoRegen and left paddle braking whenever possible. Smooth driving always, of course. Light foot-braking, if necessary. Does LIGHT foot-braking recapture kinetic energy for the battery? Is ZERO regen setting best for straight-and-level driving? I don't know the answer to these questions.
     
  11. NeilBlanchard

    NeilBlanchard Active Member

    Two foot driving? Not me! I am a practiced ecodriver - I averaged 47+MPG over 10 years, in a 30MPG car. And in our 5 EVs, I average 5-5.5 miles per kWh over the whole year. In our e-Golf (which coasts by default), I average 6-6.2 miles per kWh in the summer.

    Coasting USES the energy to move the car forward - so it is losing far less energy than regen. I do use regen - but only when I want to slow down - LIGHT use of the brake pedal uses regen (on any EV other than a Tesla). In our Leaf, and Bolt, and Smart EQ - I shift into neutral when I need to coast, but you have to learn when to do this - in the e-Golfs, you just coast whenever you can, without having to learn anything.

    The "experiment" has been done by every hypermiler / ecodriver out there. Having low rolling resistance tires, properly inflated allows you to coast in many situations. Not having to perfectly feather your right foot, and not having to watch the dash - just lift your right foot, and coast every time, is the way to go the farthest on the least energy.
     
    Jared Potter likes this.
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  13. If you're only using 0 Regen because you're "playing" with your foot all the time, as mentioned it is poor driving skills. I've seen write a few drivers who (in ice cars) pulse drive. That is accelerate a little, then cost a little, and back to accelerating. Terrible driving and a waste of energy both in ice and EVs.

    Light foot breaking does Regen, but it also engaged the friction brakes.

    Is zero Regen the best? I believe not. Because of you're good at using your foot, you can play better with the "gas" pedal to accelerate, coast and Regen.

    But in the end it's personal preference.

    Sent from my moto x4 using Tapatalk
     
    Jared Potter likes this.
  14. I use ECO pretty well all the time, and almost never touch the paddles. Works perfectly for me. Just the right amount of slow down controlled by how much you let off the throttle pedal (regen), and then with a final brake touch just before a stop. And in the mountains, worked well also, as I almost never had to brake (except a few times to cancel the ACC around corners). With ECO you still have full power (or so it seems to me) when you want. Just push the pedal to the floor, and it goes.

    I am not even sure how "coasting" could be used where I drive. I am almost always in traffic (even in the mountains), and coasting would not allow sufficient control for deceleration when needed. And would have a lot of cars cutting me off if I started slowing down so far back to not have to use much brake when coming to a stop. And the drivers that stayed behind me wouldn't be too happy either.

    So I just don't see the practicality of the coasting method. The auto regen in ECO gives me full control, and less work than using the paddles. I actually don't use it to conserve energy (my charging is all free anyway), but it is just a better way to drive the car for me.
     
  15. NeilBlanchard

    NeilBlanchard Active Member

    Driving with no regen on the accelerator changes how you drive, and no amount of "skill" can do better than coasting. I find that I can coast 20-30% of the time, at least, so that means I am consuming less energy, and using it better - and by definition, I don't need to reclaim much from regen.

    Regen loses a fair amount of energy; so by definition you will always lose some. If you use the kinetic energy to move the car forward - you are using it more efficiently, because you only lose to aero drag and rolling resistance - both of which are also part of the equation with regen.

    EVs do coast when you put them in neutral, or when they are setup to coast in D. They simply open the circuit, and the armature just spins - which is like a flywheel. They don't consume any energy when they are coasting.

    I understand the physics of things - and indeed it is the fact that that you cannot have perpetual motion, that shows that regen only without coasting will always use more energy, vs coasting some of the time.

    You can use paddle to get regen - or you can shift into B, or you can simply press the brake pedal. If you press too hard and transition to the friction brakes - then you were driving too fast / too long on the accelerator.

    I hope that folks will try this, and try it for at least a couple of charges. Keep track of your range, and compare other conditions - temperature, precipitation, elevation changes, traffic - and driving your familiar routes. I think you will find that you can be more efficient when you coast.
     
  16. XtsKonaTrooper

    XtsKonaTrooper Active Member

    How much range do you get on your Kona with a full charge.
    I know its a different argument as it only refers to regen production but when i had my Ionic PHEV, my numbers were similiar in Sports mode vereses hybrid mode. I might have used more gas in Sports mode but i regenned enough at high speed braking that it charged up my battery way quicker then staying in hybrid mode. Plus the added convenience of sports mode was faster acceleration if i needed it and more stiffer steering/suspension.
     
  17. Not disputing the efficiency of this (and I am not about to try prove you wrong), just the practicality. Don't other cars (and passengers) get annoyed with you with that type of driving? I would be afraid of inviting road rage if I did this.
     
    Kamloops_KoNa and XtsKonaTrooper like this.
  18. NeilBlanchard

    NeilBlanchard Active Member

    The Ioniq Electric coasts by default, and it is one of, if not the most efficient EVs at the moment.

    Why would you say that coasting annoys anyone? It is smooth and totally normal speed, and nobody can probably tell.

    I use all the road candy - down slopes - that I can, and I often end up catching up to "normal" drivers. I also carry more speed through turns on occasion, so ecodriving may not be what you think it is.

    Again, I hope that folks will try it out - because if you get more range "for free", what's not to like?
     
  19. I guess I’m not totally understanding what you’re defining as coasting and what you think you’re accomplishing by doing said coasting. If you’re on an open 100 km/h freeway with no turns, hills etc. Accelerating to 105km /hr and then “coasting” to say 95 km/h then repeating is somehow more efficient then Continuously applying a small amount of energy to maintain 100 km/h... it’s why cruise control works so well on open flat roads, the computer can make many hundreds/thousands of micro corrections to maintain the optimal power output for cruising. I wouldn’t at all call that coasting. Where Regen and “coasting” can benefit, perhaps where you’re thinking of coasting is the ability for us to anticipate and throttle our peaks of hills and Regen to maintain control down a hill and then anticipating the point to start putting powering into the next uphill. ICE cruise control are usually incredibly inefficient at maintaining efficient operation in this type of driving.
     
  20. Because you would have to start slowing down so early leaving a large gap to the car in front of you. The cars behind you would want to change lanes and get in front of you, rather than being held up behind you waiting to slow down.

    I am not new to hypermiling. We traded in a Prius C to buy the Kona. Just for interest and a test, I tried to get the fuel consumption as low as possible, and slowing down early and accelerating gently certainly helped. But it sure didn't make other car drivers around me very happy.
     
  21. XtsKonaTrooper

    XtsKonaTrooper Active Member

    The reason, i asked if you owned a Kona is because, your theory is that coasting is more efficient and you discount using regen which is known to charge more energy.
    With your thinking, if you owned a Kona, your range should be huge or might even be latter, especially if your not using a pretty good regen system in the Kona.
     
  22. NeilBlanchard

    NeilBlanchard Active Member

    You are describing pulse & glide, which is something that ICE vehicles need to do to stay in peak efficiency. EVs are so much better efficiency at almost any RPM, so it doesn't help to P&G. But EVs don't idle so coasting is also better in an EV.

    I am talking about coasting "opportunistically" - down slopes, or when you need to time a traffic light, or in many various situations. Once you try it, you find many places where you can maintain speed, or even gain speed - when you need to carry on driving. I don't know about you, but most of the time, I drive along much more than I slow to a stop. Coasting is a technique for driving forward, and when you can anticipate a stop. Regen only is needed at the last few bits of the drive, when you have to come to a stop.

    If I see a red light ahead, I start coasting and try to time it - so I never come to a stop. If I don't have to accelerate from a stop - that saves a lot of energy.

    Highways are rarely flat, so I coast when ever I can. You would be surprised how often you can coast.
     
    eastpole likes this.
  23. NeilBlanchard

    NeilBlanchard Active Member

    I have been ecodriving since 2007, and I saved thousands of dollars on gas, in my 2005 Scion xA - it was rated at 30MPG Combined. I kept track of ALL the gas I put in it, and before I started ecodriving I averaged about 37MPG. I was commuting 44 miles each way, on VERY busy roads. I could drive it in 55 minutes with no traffic, but typically it took 1:15-1:20 on good days, and it took over 2 hours on bad days. My worst day was well over 4 hours.

    I had that car for 10 years and put over 168,000 miles on it - I never had to replace the clutch. By the end my OVERALL AVERAGE was over 47MPG for the entire 10 years, through New England winters - everything. I got up to 6 tankfuls during the summer that I averaged over 55MPG for the tank. It had a 12 gallon tank - I went from roughly 375 miles / tank to about 490 average. Those peak tanks were well over 600 miles.

    I have driven 5 EVs over the past 5+ years (my family has 4 drivers), and we have 3 EVs and NO GAS CARS. My extended family has had 12 EVs.

    Our Smart EQ has a 58 mile EPA range - this morning its range was 95 miles. Our e-Golf has a 125 EPA range - the most recent range was 195 miles. Our Bolt EV is rated at 238 miles, and we are charging it on the "hilltop start" mode which charges it to roughly 80% and it was at 245 miles - and I had been towing a trailer, on the highway. Last year we saw ranges 350 miles or more.
     

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