The Kona EV consumption, range and charging

As noted in the previous post, I’m using a Kona EV for almost a year now, so I can write about the experience with it.

It’s a 2022 model with the smaller battery (39.2 kWh), 11kW charger and heat pump. There’s also a 64 kWh battery option which, according to reports of other people, is much better for long trips.

However, I think even this smaller battery shouldn’t be just dismissed. Sure, there are compromises about it, but it’s far from a car that „can’t get anywhere“.

Consumption

Consumption is a strong point of this car. Hyundai boasts quite low numbers and I can confirm that they are, in a sense, realistic.

That is, if you drive in summer conditions on dry roads, you can get these numbers on a mixed road trips, or even go lower, without any particular changes to driving style (that is, driving with the flow of the rest of the traffic, not 50km/h on a highway and not drafting behind trucks).

I’ve had few trips that included some amount of highway ‒ about 20% (highways are the worst category for EVs as consumption goes) that went as low as 10kWh/100km (this is significantly lower than the official numbers).

On the other hand, EV consumption ‒ this car included ‒ is sensitive to many factors and vary a lot. During wet winter day on a mostly-highway drive, I was able to get over 20kWh/100km.

While both are somewhat extremes, the difference is twofold.

Range estimates

The car estimates how much range is left in the battery. This is based on recent past driving. It doesn’t take the planned trip into account in any way (in this trim, it doesn’t even have built-in navigation, so it has no chance of knowing where it is going).

This means, if driving style changes, the estimate is wrong and the driver should know not to rely on it for planning directly.

Most daily drives are within a safe range with enough margin and each owner learns fast not to worry about them.

The range estimate is useful for keeping an eye while driving long trips and trying to get as much from a single charge as possible. Simply comparing the estimate with the distance. While the estimate might be wrong initially, it’ll get better and the margin will either increase or decrease. This gives an early warning that it might not be enough to get to the destination and a charging stop earlier might be needed.

For estimating and planning longer trips, one can use a tool like ABRP. But it has somewhat conservative information about the consumption of this car (maybe even about other cars). I’ve adjusted the „Reference consumption“ to 150 on summer tires and to 175 on winter tires. I suspect the car is sold in larger numbers somewhere in Scandinavia with different tires and this offsets the tool’s estimates.

Non-linear percents

One quirk worth knowing is, the battery percents are not based on kWh left in the battery, but on Ah in it. This may look like an overly technical detail, but the result of that is that a percent of battery at the top (eg. between 100% and 99%) means more distance than the percent at the bottom. This is because the voltage of the battery drops with the state of charge.

In other words, the percents are disappearing faster when the battery is near empty.

The estimator showing kilometres tries to account for that.

Factors influencing the consumption

There are many factors influencing the consumption. However, some of them seem to be different from common „EV folklore“, at least according to my observations.

Speed

Driving speed is likely the biggest factor. The effect is almost not observable to about 70km/h and is small to maybe 100km/h, then it rises more prominently.

There seems to be a significant rise somewhere between 120 and 130. There’s also an increase of noise at about these speeds.

Considering the highway speed in Korea is 120km/h, I suspect they tuned the aerodynamics for „their“ speeds and somehow neglected our European top speeds (130 is actually on the high end of allowed speeds across the world).

Lowering speed on the highway can save some energy, lowering speed in city driving likely not.

Tires

As noted indirectly above, winter vs summer tires have a significant influence on the consumption.

External addons

Like, roof boxes, bicycles on the roof, etc. These all break the aerodynamics and make the consumption worse.

I’ve heard that it’s often better to put skis inside a roof box than carry them bare on the roof rack ‒ even if bigger, the aerodynamics of the roof box is slightly better.

Weather effects

Wind has a lot of effect ‒ that’s obvious for a headwind, but even crosswind makes the consumption higher.

Humidity also plays a role. Wet roads increase consumption, so does fog or rain (that increases the aerodynamic drag) or simply humid air. This has more effect in higher speeds.

What doesn’t seem to have that much of an effect is temperature. There seems to be some small amount of consumption increase with cold, but all that humidity and wind seems to be more significant factor. Nevertheless, during cold days, one oftentimes get more humidity and more wind. Dry, sunny but cold day is going to be more favorable than a summer rainstorm.

There’s some energy lost for heating the cabin. With the heat pump, it’s not huge amount (the initial heating takes quite a bit, but keeping it warm during a longer drive no longer consumes much) and it can be lowered even further by using the Driver only option (which blows the warm air only through some of the vents close to the driver seat, not wasting it on the rest of the empty car). Lowering the temperature and using a heated seat can be used too, but it doesn’t seem to be a significant difference ‒ I use such setup more to keep myself alert and awake than to save energy. All in all, the difference is not significant enough to compromise comfort.

Air flaps

The car has air flaps at the front. Most of the time they are closed off, making the car more aerodynamic. They get opened only on occasion when it needs to feed a lot of air through the heat exchanger, either because of need to cool down or to warm things using the heat pump.

They can’t be operated directly by the driver and the only indication of if they are open is higher consumption at highway speeds and a kind of very silent „turbine noise“ coming from that area.

I’m going to leave some extensive observations about these and battery thermal management for a separate post, as all that was getting somewhat long.

Weight

Despite all the advice to keep clutter at home because of consumption, it seems extra weight does not influence the consumption in any measurable way (as long as that weight is closed inside the car, of course).

Considering how aggressive Hyundai cars are about using regenerative breaking, it seems they are able to regain most of what extra is used when going uphill and accelerating by going downhill and decelerating.

In other words, don’t expect your range to suffer by giving another person a ride, not even speaking about the effect of leaving the charging cable at home.

AC charging

The car is equipped with a 11kW charger (3 phase x 16A). If connected to a single-phase AC station, it can take up to 1x32A, which is about 7kW.

For those who don’t know the difference, with AC charging the car is connected to Alternating Current from the mains directly and the charger is inside the car under the hood somewhere. This is the same for public slow charging stations and by connecting the car to a power outlet (either the ordinary single-phase one, which charges slower, or the red three-phase one many people have in their garages).

Combined with the low consumption, the car can effectively „surf AC chargers“. If I have an errand day and expect it would be more total driving than the full range (which happened only once so far), I can plug the car to an AC charger at every stop that has one available. I won’t spend any extra time just for charging and it would provide the extra needed to make the whole day run. Each 30 minute charging session counts.

Similar strategy can be used if such a car lives „on the street“ without its own garage. When I was still living in a flat, most of the time the car was kept charged by surfing charges, only occasionally I’d have to put it further away from the house to a charger for a longer time (usually before or after a longer trip).

DC charging

The car is capable of DC fast charging.

Again, for people without the EV experience, in this case the charger lives in the station. The charger inside the car is bypassed and the battery is fed directly from the station by Direct Current. The station can contain a bigger and heavier charger than would be practical for the car to carry around, which allows the charger to be significantly more powerful. Using them is usually more expensive (while an AC station is mostly just the plug, some fuses and a meter, this is actually an expensive equipment). Most EV drivers use these only when in hurry and most charging happens on the AC while parked for longer periods (like overnight).

The car is willing to take up to about 46kW and a 10-80% charge is supposed to take 48 minutes. These are not top of the game numbers now, but it’s definitely faster than the up to 11kW of AC charging.

The 64kWh battery version of this car takes the same time, it has higher max power input. This is quite common phenomenon with cars that have smaller and larger battery option. It’s because the larger battery is made of the same cells, just having more of them and all the cells are charged in parallel ‒ therefore, more cells can take more total power.

For comparison, Hyundai Ioniq 5/6 boast charge time of 18 minutes and something over 200kW of max power input. As a reference, a water kettle is usually about 2kW.

Charging curve

As with any EV on the market, the car is not willing to always take the max power. The charge slows down with increasing state of charge ‒ and that’s why nobody really advertises how long the car takes to charge to 100%. Usually, it takes about the same time to charge it from 80 to 100% as it takes from 0 to 80%.

But it’s not like there would be a single steep drop at 80%. This car has a drop at about 65% to some 35kW. Another drop is somewhere around 75% (I’m not sure exactly where). Past some 87%, it charges at 13kW and will drop to about 6kW at 95% or so (it’ll also drop to lower power on AC at that point).

This is for the smaller battery with a heat pump. While the large battery always has the heat pump, there are versions of the smaller-battery one without the pump. As I hear the pump running during a DC charge, I assume it is used for more effective cooling. Without the heat pump, the only option is to circulate the coolant through the radiator and blow air through it ‒ which might (or might not) offer worse performance.

Poor man’s advantages of slow-ish DC charging

As mentioned, these are not really top of the game numbers any more. These are not terrible, considering the consumption ‒ it would be worse if the car consumed twice as much (it would also make the range on the same battery half what it is).

Anyway, these conservative charging speeds have two small advantages.

Most of the chargers in Czech republic are 50kW ones. Due to the battery voltage and limit of 125A on the cable (the common setup of the 50kW chargers), these limit the car to some 44kW, which is very close to its limit. This means I can just pick any charger based on amenities available around for me than adjusting to the needs of the car.

With more conservative charging speed, the car is less sensitive to battery temperature. The car doesn’t have an option to preheat the battery before reaching the charger, but it mostly doesn’t need it. If the car is connected to a DC charge first thing on a cold morning, it’ll limit the charging speed for few minutes (before it heats up by charging), but an hour of driving is enough to warm it even during winter. This means, if one starts a trip with reasonably charged car, the battery would be warm by the time charging is needed.

Occasional failed handshakes

From time to time, the handshake between the car and the DC charger fails. It’s often the case with ABB chargers (I’ve never seen it on an AC charge, but the communication protocol for these are significantly simpler and less fragile).

I’ve observed that this is likely related to the car having the charge port in somewhat unusual location (it’s on the nose and quite close to the ground). Often, one needs to twist the cable, because the operator expected the port to be from the side of the car, not from the front.

I’ve always managed to make the handshake work by either holding the connector in place during the handshake or twisting the cable the other way around. Don’t give up on the first attempt and drive away.

Long-distance travel

There are several ranges that come into play around an EV.

Even during winter, I assume a place 100km (a bit more in summer) away is within a round-trip range ‒ if I charge to 100% before leaving, I’m almost sure to get back home without a need to charge. In winter, this might mean I’d have to drive slightly slower on a highway (if the weather is bad and most of the drive is on the highway) and that I might arrive home near empty (but that’s OK as long as I’m sure to get home, I have a charger there).

Similarly, I can reach a place about 200km (more in summer) away if there’s a destination charger there and stay there for a while, so I can go back again. The presence and reliability of destination chargers is not always sure, therefore one might want to have a backup plan.

Then there’s something I’d call a comfortable range. It’s around maybe 300km away for me. This already requires a stop to charge, but I’m likely to want a stop myself. I don’t need a full recharge (or to 80% or so), only maybe 100km, the charging would take about 20-25 minutes. That might be a bit longer than necessary for a minimal toilet break, but about OK to also buy a cup of tea (it’s surprising how long a „just stop for a toilet“ actually takes in any car).

As the car has active cooling of the battery, it can do arbitrary number of DC charging sessions in a row. That makes it possible driving long distances, at least in theory. After the first longer leg (as it can start with 100% charge), the optimum lies in something like 120-180km of highway driving and 30-40 minutes of charging. I also suspect it might be better to lower the driving speed to something like 120km/h ‒ lower consumption means less of charging and could mean arriving at the final destination sooner.

On a trip from Czech republic to Croatia (common summer holiday destination and kind of a benchmark/argument of many people why EVs „suck“), there might be some 5 or 6 stops. That’s probably somewhat on the discomfortable side of things. I mean, people were willing to make these journeys with several hours of border control queues, but one would still desire for something better.

I’d also note that there are EVs that do better ‒ including the bigger battery variant of Kona, which (according to several tests) can get there with just two stops (1, 2).

This is likely the lowest-end EV that’s even capable of this kind of long-distance travel. Cheaper EVs either don’t have active battery cooling ‒ and won’t be able to do more than one or two DC fast charges in a single day (further charge would be incredibly slow due to protection of the already hot battery). Or, some even don’t have the option to fast-charge.

En-route adjustments

There’s one trick worth knowing. If you know you’ll not reach the destination, but only by a small bit, it’s either possible to stop and charge (in most places, there’s at least one charger every 30km or so ‒ this is with exceptions, though, and it is worth having a look at them before making a longer trip). The alternative is slowing down a bit, especially on the highway. Such thing will lower the consumption and sometimes make it possible to get to the previously planned destination faster than by stopping to charge.

Watching the estimated range and adjusting speed based on that is something that can be done and this is in part how some EV drivers surprisingly often arrive home with below 5% of battery, but never get stranded with 0% on the way.

Charging infrastructure

DC infrastructure

My personal opinion on how good or bad the infrastructure is here in Czech republic. I’d say there’s mostly enough coverage of DC chargers around. My view is likely influenced by the fact my car is well satisfied with all these 50kW chargers, though. And of course, as more EVs appear on the roads, we still will need more.

However, not every charger out there has reasonable amenities around. As the expected stay of a driver is 30 minutes or longer on a 50kW charger, a charger that doesn’t even have a toilet there is kind of useless.

Against what general non-EV population thinks, chargers aren’t commonly broken (sometimes glitchy ‒ see the note about failed handshakes) and it’s easy to pick a location with more than one stall, where the chance of all chargers being in use is rather low. That is, reaching an occupied or broken charger isn’t a common experience.

AC infrastructure

This is where I believe we need more infrastructure. A car is parked somewhere most of its life and usually, when I drive somewhere, I spend at least a little time there. This time can be spent charging ‒ but only as long as there’s a plug, AC station or something like that.

Shopping malls are mostly covered already by these. But we still lack them at other places where people spend time ‒ ZOOs, castles, hotels, restaurants, ski lifts. And near estates, block houses and other places where people tend to live ‒ both for the people there and for visitors. This is, to some extend, covered in Prague, but other cities still have a lot to catch up.

Optimally, there should be a charger on every street and bigger parking lot. Having a destination charger available in a destination basically doubles the range at which there’s no need to charge on the route and makes cheaper small-battery cars more useful.

All in all, while we need some high-power DC charges by the highways and main routes, it’s possible to build significantly more AC chargers for the same money and would be a better investment. It’s just, opening a 300kW charger is something that can be shown in news and gains publicity, while installing 20 power outlets on 10 different parking lots is not as glamorous to boast about.