Do you actually drive this?

  Well, yes, that's what I got it for.  I enjoy it greatly, and I also enjoy the magic behind the curtain.

It's hard to know where to begin discussing driving dynamics.  There are multiple nuances in play at once, but many of them are hidden or second-order effects.  Let's start with the most visible fundamentals emphasized in the sales literature for the Kona and other electrics -- the drive modes or "curves", and regenerative braking.  There isn't a whole lot else for a driver to mess with or change!  Most electric cars have no gear-ratio shifting, just a single-speed reduction gear from motor to wheels which is quite enough to cover the entire speed range of the vehicle.  Electric motors have much wider RPM limits than internal-combustion engines where useful power is produced, including down to a total standstill; they don't have to "idle" at 900 RPM and be carefully kept alive while applying power to a drivetrain.  It makes electrics very simple to drive, once you figure out how to shift one to "D" in the first place -- it's a big golf-cart, you have a "go" pedal and a "stop" pedal to control speed, and you just steer it and keep an eye on the guess-o-meter range estimate.

There are many ways to describe the experience.  This review from Robert Llewellyn and the Fully Charged team, which I've referenced before, is worth a watch for comparison.  It presents a nice rundown on the observations of a long roadtrip, where the keyword seems to be "effortless".  For the most part, I agree with that.

Like most other vehicles, the Kona applies some "creep" in the selected direction when the brake pedal is released from a stop.  It's no longer a function of physical automatic-transmission drag, but as described in several references, that old effect became such a natural and expected kinesthetic thing it's now considered a safety feature [updated link].  Under a few circumstances the Kona will remain still with no feet applied to the pedals, notably during a "hill hold" scenario, but usually it will start gently and smoothly moving in D or R.  [And making that silly Jetsons-jingle, unless you've pulled the speaker.]  Unimpeded drift rate seems to be about 4 mph on the flat.

Now we press a pedal, and drivers are given some degree of control over what happens next.


Original Prius HSI pedal curves Those who have been around the hybrid circuit for a while might remember this diagram, from early discussions around the third-generation Prius and my reflections on how it related to the "hybrid system indicator" aka factory-provided sweet-spot meter.  For a fully drive-by-wire accelerator pedal, a computer can apply any response curve it wants, a mapping between pedal position and motive force, and that year of Prius introduced three selectable driving modes.  Vintages of Prius before then had a single pedal curve but it was fairly "slow-bottom", perhaps most like the "ECO" here than the others, which I rapidly came to appreciate in mine because it allowed a lot of fine control over low-speed electric maneuvering.  The curves and drive modes were often misunderstood, however -- selecting any mode in no way changed the maximum power output of the car, it just took a different path reaching that point.

What the Kona drive-mode curves might be The Kona feels like its curves are a bit farther apart at the low end where the pedal first begins to be pressed, so let's fatten them up a bit in that region.  [This is all qualitative; there are no hard numbers here.]  Between Eco, Normal, and Sport, responses to foot travel just off the peg are *quite* different to the discerning "butt-dyno".  The Eco response feels closest to the second-generation Prius, which made me immediately feel so at home with it.  In Sport mode, a gentle tickle of the pedal makes the car LEAP forward like an uncaged animal.  Even "normal" is too jumpy for my taste, and I've found that response like that is also the only choice for a lot of ICE car throttle setups.  A surprising [and to me, disturbing] number of drivers seem to like the perception of "quickness", but then at the same time often *complain* about how all that electric torque makes it too easy to spin the front wheels when taking off from a light.  Well, duh.  "Fun to drive" has many different manifestations, y'know.

  The most notable feature unique to electric or hybrid drivetrains is the regenerative braking capability, where the decelerating car pushes the motor and produces energy that the battery can store.  Regeneration is probably the single largest factor helping the energy economy of these vehicles, because stopping two+ tons of car requires a lot of that.  Even the earliest electrics a century ago had rudimentary regeneration, because their makers realized the potential [!] energy savings.  Regeneration can be configured as some amount of "drag" feeling when the accelerator pedal is released, like gearing a step transmission down, and/or fully integrated with braking so that pressing the normal brake pedal brings in as much productive regeneration as possible before resorting to using hydraulic pressure at the wheels at all.  Modern power electronics and control systems have made it all much easier.

Even with all the advances, regenerative braking is also one of the least understood sciences on the road.  While researching around for my own EV decision I saw a lot of confusion and misinformation posted in forum threads and even supposedly "informative" articles.  In principle, it's simple -- the substantial force of a car slowing to rest is used to spin a "generator" against a controllable load, utilizing the same drive shafts, gear train, and motor that got it going in the first place.  But many people still seem to think it's still done "in the brakes" somehow, as though friction is magically turned into electricity captured in a battery.  It is often an eye-opener to the public when the simpler reality is explained, along with how the physical brakes get very lightly used and pad/shoe changes will be *very* infrequent as a result.  Once they get the concept, then they have to also realize that it's not a 100% capture and replay, there are always losses through the system.


Zero regen pedal curves Regen level one curves Higher regen levels  
Regen 0 Regen 1 Higher  
Besides adding some color to the three different drive curves, now let's add the effects of the regeneration level setting from the paddles.  We've extended the force axis with a negative region, because the motor and electronics act with negative force on the car and slow it down.  I've combined regen levels above 1 into a conceptual "higher", because the decelerative force from 2 or 3 makes the car completely fall on its face, and can easily cross the mandated 1.3 M/s^2 threshold where the brake lights need to pop on.  That mode of "one-pedal driving" seems surprisingly popular, even if it makes everyone in the car feel like their necks are getting whipped back and forth.

For rough comparison, regen 1 feels about like a Prius in "B" mode.  Even that is still too much for a lot of almost-float conditions.  Another mild annoyance is that the manual *lies* about regen 0 being a settable default for any of the drive modes -- the lowest setting is 1, so every time I boot up and get going I have to bap the right paddle once to get it back to 0 for the rest of that run.


All curve groups together When we put all of the curves back together, we get a mess.  Between three drive-modes and four levels of regen, a driver can select any of a dozen wildly different response curves!  This allows for tailoring the car's behavior over a wide range, but one should still understand *what* it is they're changing.

Preferred eco, zero-regen curve I have tried about every different combination of the settings, and keep coming back to this -- "eco" curve, and zero regen.  First off, having a car dive into a steep slowdown and possibly not show it in the brake lights just because the go-pedal was released seems like utter folly, in these days of ubiquitous aggressive tailgating.  Second, being perpetually in a "go-or-slow" scenario, with force always applied one way or the other because finding the "glide" in the middle is too difficult, is simply wasting energy.  Momentum is also energy, and gets us down the road without us needing to change anything about it!  Why mess with that until we have to?  Just letting a car roll is the most efficient driving.
 
  And here's the other major factor that renders auto-regen levels to somewhere between academic and annoying.  The service braking in the Kona *is* fully integrated, with regeneration handling as much of the stopping power requested from the service brake as possible up to some very generous limit of kilowatts.  That comes with the mild caveat that stopping should be smoothly applied.  This is easy to prove with a simple test: set regen 0, find somewhere to do a nice long even stop from a decent speed, preferably downhill, using only the brake pedal.  Then immediately get out and feel the brake rotors, front and rear.  That's not where the energy went, plain and simple.  The Kona, like the Prius, does it right, and testing the working basics of that doesn't even need brake pressure monitors.

After extensive experimentation I dropped my conclusions into a long rant over at Insideevs, in part building on what some other posts had expressed before.  Naturally, a few haters came out of the woodwork to try and shoot me down, but whatever.  Those are probably the same people spinning their front tires on wet leaves and whining about it, while deluded that they're doing really well at 3.7 mi/kWh consumption.

Regeneration has its limits, though.  It amounts to a burst of *very* rapid charge into the battery, sometimes more than it can safely handle.  A hard stop at speed can easily produce over 300 amps, and while large EV batteries can usually suck that up for a short time, it's far more than most smaller hybrid batteries can accept.  Regeneration control has to change dynamically and fast, responding instantly to driver demand, road conditions, and variable limits based on factors like temperature.  It also has to know when to quit, such as over complex bumps when forces and currents change too quickly to maintain control of.  We can sometimes feel that relinquishing of control as a brief little "sag" in braking force as hydraulics take over, because the ultimate task of the system is to stop the car.

What's interesting is that even in regen level 0, a *tiny* bit of energy recapture happens -- all of -2 to -4 kilowatts or so, and vanishes down to 0 on shifting to Neutral.  The difference between D and N are indistinguishable by feel, so there's no particular advantage to entering a full "neutral glide" at speed like we sometimes need to do in the Prius.  Most of that power trickle seems to go to keeping the 12V system alive, as its voltage reliably shoots back up to that 14.7 float in the process.

If the car's speed is above some minimal level like 2 mph, one can freely shift between D and N and back without having to press the brake pedal.  It's only at a full stop that stepping on the brake is needed to move to D, which I suppose is a reasonable assumption such that an inadvertant tap on the button doesn't unexpectedly *start* the car moving.  But if it's already moving forward, that was the driver's intent so no lurchy additional brake-press is needed then.  Knowing this is important to me because there are several circumstances where shifting to N on the fly is useful.  One is to deliberately use the friction brakes to slow, usually to clean rust off the rotors -- a couple hundred feet of gentle hydraulic-only braking takes care of it, and then it's back into D.  [Moving to N *during* a braking event immediately disables regeneration in just about any hybrid/electric system, and is the easy way to reproduce that "hydraulic takeover" transition to learn what it feels like.]  I also usually shift to N at stoplights and such -- it allows sitting there and watching the rearview to know when to pulse the brake lights toward someone approaching from the rear, without having the car try to creep forward in bursts.  It also makes for a much smoother stop over the last couple of MPH.  Being able to do all that without looking or fumbling was the main reason for the shift button mod to make it easier to find.

Overall, once all these things are worked out and gotten used to at the muscle-memory level, the experience of driving is very smooth and pleasant.  I don't really notice the road/tire noise that others complain about because the windows are usually open some way, my hands are locked into a very stable position on the wheel crossbar, and I'm relaxed and one with the machine just like always.  And pulling 5.5 mi/kWh on a summertime mix of local/highway, I might add -- that's about like high-fifties MPG in a Prius.  The *only* differences I really notice on getting back into the Prius are the longer expanse of dash-top in front of me, and a slightly heavier steering feel.  Oh, and of course that "old car smell".


  Eking out economy

Eco mode downhill Eco mode uphill
downhill uphill
In ECO drive mode, the main display changes to some conceptual assistive layout designed to perhaps guide a driver to best efficiency.  Nobody's been able to get Hyundai's take on what the varying arcs over the top of the circle are really supposed to indicate, but I think I've got it mostly nailed down.  The teal arc across the very top seems to change size according to uphill or downhill pitch of the car, but it varies somewhat with speed and is rather delayed due to calculations from wheel-speed and accelerometer data.  It widens on the uphills presumably to indicate that it's okay and expected to push harder up the hill, and narrows to suggest minimal pedal to essentially coast downhill.  The white arc just inside of that simply indicates absolute pedal application, which is even more useless because it doesn't take regen level settings into account.  In a higher regen setting, the pedal has to be held substantially pushed [showing a lot of white arc] just to glide, which is totally misleading.

My foot demand was about exactly the same in these two shots, with the terrain at the time somewhat reflected in the outer arc and obviously needing a lot more output than suggested in the left-hand one just to keep going against air resistance.  Oh no, into the red zone!  But in general, driving in a "constant power" model with a bit of speed loss on the uphills and getting it back on the downs is overall more efficient than trying to rigidly hold a speed.  Thus, in this car as well as the Prius or any other, cruise control tends to defeat the purpose if one is trying to maximize range.  Interestingly, the ECO mode also allows configuring a soft speed limit, past which power sent to the wheels will be limited.  That's almost a rough high-limit cruise-control in itself, where a driver's foot can relax into a "just anywhere" held position on a sufficiently open road for a while.  Beware, though -- past a certain pedal demand point, the speed limit is suddenly defeated and the car obeys *that* level of command with one's foot way into it asking for lots of power.  Surprise!  Great if you want to pass someone like a total dick, I suppose.

All four tires are kept around 60 PSI, which is perfectly safe to do and makes for much better rolling and wear profile.  The TPMS sensors or the system they talk to tops out at 51, which happens to be the sidewall rating of the stock Nexens.  So basically when starting off, I can check that they're at 51 all round and assume they're higher, and if any pressures show lower it's probably time to go around and air them all up a bit.

What's not in these shots is the "power/regen" indicator along the left side, which isn't all that much use either.  It has a segment *hysteresis* of up to 10 kilowatts, e.g. my foot has to go from 10 kW to 20 kW before it lights the second bar of the graph, and then back down under 10 before it drops back to one bar ... and then a similar game between 20 and 30, etc.  The little yellow number in the "electricity use" head-unit display, or even a battery-current reading taken via OBD2, is more useful and immediate.


  Driver assistance sort of isn't

  This particular car is the "SEL" lower-end trim, and doesn't have some of the extra comfort/safety stuff included.  That's fine, I didn't really want that stuff so it was appropriate.  It does have a "lane keep" system that uses camera vision to try and stay centered on the road, and in the more assistive modes gently nudges the steering back toward center unless you're signaling for a lane change.  It's amusing for all of about 20 minutes, and then we realize what all of the bugs in it are.  The major one is when an off-ramp lane opens to the right before a highway exit.  The LKA dutifully tries to re-center itself in that rapidly widening "lane", and guess what?  Now you're heading straight for the gore area and off-ramp divider.  Once the lines get too far apart it gives up and cuts out, but the stupid deflection toward disaster has already happened.  It also seems to be no good when lines are converging, changing its little icon to show "inactive" until a lane re-forms to something that looks normal to the little camera in the windshield.  At other times it can be self-negotiating a gentle curve nicely, and then just give up for no obvious reason and leave the car to dive off the roadway without so much as the warning beeps it's supposed to issue.  Not only is it no substitute for a watchful human, the human actually has to fight the damn thing sometimes.

Between LKA and generic cruise and confusing "auto-hold" settings and clumsy features of the paddles, all of this feels more like "driver interference" than "driver assistance" to me.  LKA might be a useful brief reminder to use once in a while if I'm poking at the GPS, which is probably my worst window of attention vulnerability.  I'll give it all an honest go and try to understand how some people might like to use these features, but within about ten minutes I'm like "my airplane" and go back to actually driving the vehicle.  At this point I can often tell just by looking at other cars and their motion dynamics when their drivers are trying to rely on these overly-automated nanny systems -- that so often get it wrong where real-world safety is concerned.  Most notable is those fucking "auto-follow" radar cruise controls, which I am constantly having to yuppie-button off my ass because their supposedly "safe" systems still ride too close.

As much as things may have advanced recently, if you can spin the tales of people sleeping inside moving Teslas as "progress", we're stll a long way from fully autonomous vehicles that can deal with all possible conditions.  Perhaps the best indictment of the human factor comes from a section starting around 05:40 in this "Autoline" interview where a senior figure *in the industry* of autonomous-vehicle research learned that his wife turned *off* all the safety crap in her new car because it was just too annoying.  At least she was able to; that may not be true in their next car.  There seems to be growing agreement that true "autonomy" is going to need a lot of direct infrastructure support, and be kept separated from where human drivers are still doing their thing, at least until the very last human driver is forcibly removed from the loop.

Good luck getting that to happen.


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