Team-BHP (https://www.team-bhp.com/forum/)

-   Electric Cars (https://www.team-bhp.com/forum/electric-cars/)

-   -   Study: Range ratings of EVs are far less reliable than that of their ICE counterparts (https://www.team-bhp.com/forum/electric-cars/265159-study-range-ratings-evs-far-less-reliable-than-their-ice-counterparts.html)

The range on a single charge is often the first thing to notice before making an EV purchase. While EVs do provide a range rating, which can be compared to an ICE-powered vehicle's DTE estimate on a full tank, a new study has found that the ratings in EVs are far less reliable than on their ICE counterparts.



SAE International has published a study which states that most BEVs fall short of their electric consumption and range label values. Also, when combined with other external factors, the difference between the label value and the actual on-road consumption further increases. ICE vehicles, on the other hand, performed 4% better in terms of fuel efficiency than their rated figure. The study found that 66% of all ICE cars tested achieved an MPG figure higher than their labelled value.

As per the study, EVs, on average, faired 12.5% worse than their rated range. Only 17% of the total EVs in the test managed to surpass their range estimates. As per SAE, EVs are allowed an adjustment factor of 0.7 or higher - meaning that the estimated range is 30 per cent lower than the calculated range. This adjustment factor, coupled with other external factors, means that the real-world range of EVs is more likely to be lower than advertised.

For the study, SAE compared the range rating of 365 ICE-powered cars with 44 battery-electric vehicles. All cars ran through several tests by Gregory Pannone, former head of fuel economy at Chrysler and Dave VanderWerp, director of vehicle testing at CarAndDriver.

Source: SAE International

Link to Team-BHP news

EVs are also very susceptible to varying driving conditions. Ice cold weather? Range drop. Drive above 100 kmph? Range drop. Accelerate hard? Alarming drop!! Mountain roads & a full load of passengers too. The considerations are many.

Also, assuming that you will never let your EV battery drop below 20% (too much range anxiety), your real range is 80% of the actual driving range. This is unlike a petrol car that you can drop to 5% tank level because of the abundance of fuel stations & 5-minute top ups. Imagine driving up to a charging station with 5% battery level and it doesn't work (there are currently many software, hardware & compatibility issues).

Isn't this true for ICE cars as well - ICE cars are also very susceptible to varying driving conditions. Bumper to Bumper traffic? Single Digit FE. Drive above 100 kmph? FE drop. Accelerate hard? Single digit FE!! Extreme weather? FE drop. Mountain roads & a full load of passengers too?? FE drop.

Also why would one wait for 20% to charge their car. On major highways there are multiple chargers, you can charge earlier as well it is all based on the distance you want to travel. Yes on some highways chargers are less you might reach till 20% before finding a charger but that is changing fast. Also, all this is only valid if you are travelling more than 280 kms in a single go.

Not really. An IC engine is also sensitive to these elements but nowhere as much as an EV is. For instance, driving beyond 100 in an ICE doesn't always cause a drop in fuel efficiency. In fact, some cars actually do better in terms of FE between 100-120 than they do below these speeds (tall gearing and turbocharging play a major role here).

The same goes for accelerating hard. A mass market turbo petrol if driven hard will do bad numbers, but it can recover quickly if driven sedately. An EV can't do this just as quick.

The major factor that sets IC and EVs apart is the lack of a gearbox. In an EV, the higher you go in terms of speed, the lower your range. This isn't always true when it comes to IC cars because of what I explained above.

Today I was watching reviews of Fronx and Verna, they have a rated range of 20kmpl, but in city they hardly give 14kmpl.

It's not due to the gearbox, even if a gearbox is used in an EV the benefit in terms of range is very less. EVs are so efficient that aerodynamic resistance at high speed causes lower range, ICE are so ineffecient that aerodynamics is not an issue.

This is only true for cars with tall gearing. Previous car i was driving was Rapid Diesel automatic - 7 speed DSG. Yes it is used to give 20-21 kmpl per litre at 100 also but it would given even more had I been driving it at 90. But the same is not true for the Verna and City that we have in the house. Mass Market cars with 5-6 speed gearbox don't give good FE at high speed. Sweet spot is usually at 80-90 or whatever speed keeps engine rpm below 2000

Same is true for EVs, they do brilliantly at sedate constant speed driving.

No it is not about the gearbox, it is about aerodynamics. Till now most of the mass Market Indian EVs are ICE cars converted to EVs. Hence aerodynamics were not designed keeping low drag requirement in mind. If you look at premium EVs don't have this problem as much because they were designed as EVs - example - Ioniq 5, EV6 and more

Let me explain my 2 cents here.

I drive Audi Q4 which has 82 KWH battery, of which 77 KWH can be used. EPA is 265 miles.

I divide 265 by 77 (available battery). I get 3.4 which is called miles per KWH. This number gets displayed in the dashboard. As long as I see 3.4 , it means I'll get full 265 miles.

This miles per KWH varies based on temperature, as/heat, elevation etc. If it drops below 3.4, that means I get low mileage.

This is how I calculate:
My battery shows 40%
Miles per KWH shows 2.8

If I go by percentage , this would mean I should get 40% of 265 miles = 106 miles remaining.
Instead of that, I take 40% of available battery which is 77 KWH. I've now 30.8. Multiply 30.8 with Miles Per KWH 2.8, that gives me 86.24 miles.

I believe elevation, external elements affect gas cars as well but we don't have this much of data available to us. Also we don't care as there are gas stations everywhere.

Please note that EV's have regen braking. When I drive in bumper to bumper traffic I even get >4 miles per KWH which effectively means I get more range than EPA.

One question for the forum: AUDI Q4 is imported from Germany. For the same model the range is 330 miles and in the US it's 265 mi.

Off topic: I went for glass replacement. Audi gave me a SQ5 as a loaner. I DID NOT like the car. It's noisy, acceleration is not linear and just do not feel refined. It's very difficult to to back to gas car.

Exactly. And turbo petrols are even worse. The diesels do fare better but they are going out of fashion. IMHO Hybrids fare the best while we transition to EV's.

True. How many times are we doing long distance driving anyway? With more fast chargers it is only going to get better and in most cases you would stop for a break anyway and the car can fast charge in the meanwhile. And for over 90% of the cases when you are not doing long distance driving, you the fuel in your home and in most homes across the world. You would never visit a petrol pump for months in an EV and that is time saved too not mention the time wasted in detours to fuel from your preferred petrol pump.

You really do not have to push an electric car hard to accelerate since all of the torque is available from get go. In real life a Tesla Model 3 Performance would leave most hypercars for dead.

Unlike ICE's EV's do not need a torque multiplying gearbox. Infact given frictional losses and additional weight of a gearbox, you would be worse off if you had a gearbox in an EV. You could, though, argue that a gearbox could be used for better performance at higher speeds but then you have to look at effort vs rewards. Personally I see no case for a gearbox in an EV.

Higher speeds at a particular gear = less range is true for every car - ICE or otherwise.

Except for the temperature, the rest of the stuff applies to ICE also. Driving conditions can make your FE go from 10 to 20 kmpl. We just dont bother about it because you know fuel is available everywhere and can extend the range in less than 10 mins

Why except temperature? I can attest to the fact that FE drops 20-30% in winter!

We had ICE two and four wheelers during their best of times proclaiming through advertisements that these deliver a whopping "xx" kmpl with an *. And at the base this * would be decoded in small font italics:-

"under ideal testing conditions"

Hopefully EV makers who are busy with FAME II and PLI for their well being think about their customers well being too and publish real life EV range figures.

I believe EVs are actually more efficient cars, and tech like regenerative braking, low rolling resistance tyres just adds to it. I've driven my Nexon EV (2021 December Model) for over 17k kilometres.
People say EVs are more efficient in traffic due to regenerative braking but this isn't entirely true. If i am to give a one line statement which sums up EV efficiency it will be "EVs are most efficient when you know where you need to slow down". The timing of breaking is of utmost importance. When in bumper to bumper traffic i find myself using the brakes quite a lot, but when out on late night drives in South Bombay i get exceptional efficiency because i know where to brake. I take my foot off the Accelerator pedal well in advance and with regenerative braking set to level 3 i get exceptional efficiency. To put in the numbers i get a 160-170 Wh/km average in bumper to bumper traffic while returning home (Santacruz East) from office (BKC) which is hardly 5km. But when out on late night drives from Santacruz to South Bombay i get a consumption of 115-120 Wh/km over a distance of about 50-60km. Mind you that all the above numbers are with AC on full time on Eco mode with temperature set to 22°C and fan speed at 1 or 2 usually.

One more point on efficiency comparison. ICE cars are also subject to vagaries mentioned by GTO above. Because the monitoring system in EVs is very precise and real time everyone complains. The avg fuel economy figures are shown in ICE cars but they are nowhere close in accuracy, when compared to EVs, as has been demonstrated by Tank Full to empty tests in the past.

I think the issue is less about reliability of the range ratings and more about the consequences of real world performance being different from controlled conditions. Especially on longer trips.

As an example: an EV performing significantly lower than proclaimed range will lead to more stress on the driver to plan and manage the battery levels - more calculations, more searching for enroute chargers, anxiety about the availability of slots, time management.
On the other hand, a significantly lower FE on a diesel or petrol car is way easier to manage with abundance of fuel pumps, shorter pit stops and nearly consistent fuel quality.

I still remember on my old Android phones (around 5 years back), making sure that the battery is enough charged at all times to last through the day was a task in itself. I was charging at every possible opportunity and also carrying a power bank just in case (which had to be charged separately every night).
But with newer phones, the battery backup and charging speed has picked up to an extent that I don’t even bother to track the levels on my phone. It’s almost a given that the phone will not shut down abruptly and leave me stranded unlike the past.

The same needs to happen with EVs where higher battery capacity, availability of recharge stations and fast charging will make this habit to perform precise tracking of the range a moot activity. Just like range to empty on an ICE car is another number on the board.

Even if ICE mileage ratings are less reliable, it’s not a serious issue except having to spend more for fuel.
In the case of EV, if the range is lesser than expected there is a lot of chance of getting stranded in the middle of nowhere.
Charging is also not as simple as filling fuel, so the range being unreliable is a point of concern for prospective buyers.
If the EV is used within city and possibly the day’s travel is planned within 50% of the possible range then getting a lower range becomes a non issue, especially because electricity when used home charging is not as expensive as fuel.

I wonder if it is 20-30% for a Tesla. Which car are we talking about here?