I built this calculator in the hopes that radical transparency would help.
It’s Canada-centric, but you can plug in local prices, gas and electricity rates, etc, and it should successfully pull grid emissions data from your area.
I’m looking for any feedback on how to make it more useful, compelling, etc.
Thanks!
I like having some pre-built configs, but it would be nice to enter my own values and other models. This is especially true for the used market, since the resale value is so low. It can be especially compelling to show how much you would save by buying a used EV.
Paradoxically, it’s also a very busy page. Maybe have collapsible sections, and some easy to read charts in one place?
This. Let me plug in Chevy Bolt and the Kona EV, for instance.
Thanks for the feedback, I’ll add a link to a blank calculator where you can load the details of the vehicles you want to compare.
Yea, I need to make it simpler, thanks for the feedback.
You’re missing tires from the maintenance list, you only have tire rotations. This will probably go in the negative column for most EVs.
How did you arrive at these 4 vehicles? Larger vehicles will necessarily have a longer payback period than smaller ones (both in cost and emissions) because they have a larger battery pack. Maybe include Ioniq 6, Polestar 2/3, and/or Lexus ES350e.
You touched on Canada-centric but US users will want miles, and you don’t specify CAD or USD.
The tire thing is FUD in my experience - and I haven’t seen anything other than anecdotal evedince that under similar driving patterns and styles there’s substantial differences in wear. My Ioniq 5 for example only weighs ~15% more than a Rav4 and less than a Honda Pilot.
When I drove a Subaru STi, I shredded my first set of tires. My station wagon, that weighed more, the tires lasted forever because I drove like an old man. With EVs, if you have fun enjoying that instant torque by punching it off every stoplight, you’ll definitely shred some tires. Accelerate smoothly and I don’t see why tires would see substantially shorter lifespan - which is what I’m seeing from my personal tread wear so far (but that’s anecdotal and therefore of extremely limited value).
I don’t know about wear but I have seen studies that concluded they have increased rubber emissions but I’m not about to go looking for them again. But being that most EVs are fucking trucks and SUVs that shouldn’t be surprising and they wouldn’t apply to small cars that weigh similar.
I don’t have accelerated wear either but I also have a very light EV.
EVs are both heavy and have a huge amount of torque. Both cause higher tire wear. But this is because North American EVs have stupid big batteries.
Any chance of adding imperial measurements for if southerners? 🥺
Can do!
Nice, thanks
Strange city and country code. What if a country has two cities with the same name?
Overall very nice, but no one does this math with ICE cars and very few people do the 5 year math of car ownership.
Would be nice to compare any ICE.
Also, the math ignores devaluation, which is a huge issue with EV. and Etron GT devalues $55,000 in 3 years.
Also, while brake wear is significantly lower, tire wear is significantly higher. There seems to be a bit of bias here. Also, no one does fuel injector service.
This highlights that EVs in Canada are overpriced.
Hmm, depreciation on my Ioniq isn’t anything like that bad. And I had a fuel injector quit in my last car at 130k. The cost of replacing all four injectors was a heck of a lot more than quoted. I intentionally lowballed service costs for ICE vehicles because people tend to (dramatically) underestimate what they spend on maintenance.
Also, the tire thing is FUD. Tire wear is higher IF you regularly use all that torque. If you floor it off every light (which is very fun) you shred your tires. If you drive conservatively there’s minimal difference. My Ioniq 5 weighs about 2000kg, a non-plug-in Rav4 hybrid weighs 1700kg, and a Honda Pilot is around 2200kg so the weight just isn’t that different from other vehicles.
Just to add to the tire wear conversation: My winter tires have lasted 5 seasons (from early October-late April), and are finally worn enough for the tire shop to tell me this was the last season for them, and I drive ~140km/day.
My summers on the otherhand were purchased from a dealership and only lasted 3 seasons (and were showing some pretty bad wear at that). New ones will be going on their second season next month, hopefully they last longer than that!
This is on a PHEV ford escape.
Ioniq are $55-60k new, $65k plus with taxes in Canada.
2022 with 60K kms is $28K. So 50% devaluation in 4 years is significant. In fact, so significant that buying these new makes no sense.
The torque causes tire wear. You don’t defy physics.
https://www.automotiveworld.com/articles/inside-the-not-so-hidden-issue-of-higher-tyre-usage-in-evs/
Ah good, we can talk physics.
Newton’s Second Law
Okay, let’s start with Newton’s second law:
F=m*a
but we’re going to flip it around to
a=F/m
so that acceleration of a body is equal to the force acting on that body divided by its mass. What this tells us is that for a given force f applied to a vehicle of mass m, the vehicle will accelerate at rate a.
Where does that force F come from? From the tires acting against the pavement per the lever arm equation:
t=F*d
or, a force F working through a lever arm of length d will produce a torque t, but again, we’re going to flip it around a bit to give us
F=t/d
Which tells us that a given torque t operating through wheels of radius d will produce a force on the pavement of F.
Now we’re going to combine the two to give us
a=t/(d*m)
So, acceleration is directly proportional to the applied torque and inversely proportional to mass which absolutely supports what you are saying at first glance.
HMI
HMI is an acronym for Human Machine Interface which is a whole mechanical design field built around helping humans interact with complex machines like cars. Now I have to admit some ignorance here, but I don’t know what type of vehicle you drive so I’ll start simple.
In my vehicles, both gas and electric, there’s two pedals specifically related to acceleration. The accelerator (sometimes called a throttle) and the brake pedal - and these pedals are remarkable devices.
The accelerator (negating regenerative braking that we’ll touch on later) controls positive acceleration while the brake controls negative acceleration. Basically, the accelerator makes us go faster (forward or back) and the brake slows us down. But here’s where it gets nuts - these are proportionate input controls. It isn’t like a light switch rather, it’s more like a dimmer - the more you press on the pedal, the more acceleration you get. The way this is accomplished is by controlling the torque applied by the motor. This is key - we can control the torque output of the motor.
Puting it all together
You are absolutely correct that the electric motors in EVs can generate absurd torque which, as we’ve seen, results in incredible acceleration. I certainly had some fun when my EV was new. But, 99% of the time, I’m driving in traffic or on the highway and my accelerator inputs are very light - the motor is generating only a small amount of torque it’s capable of producing.
Gas cars operate in a similar, albeit wildly more complex manner (the accelerator pedal controls the amount of air getting into the engine, then a feed forward control mechanism is guessing how much fuel is needed and a feedback system monitors for the presence of unconsumed oxygen or uncombusted fuel in the exhaust). The important thing is that both are capable of delivering variable torque based on operator inputs.
So let’s imagine we have two cars stopped side by side at a stoplight that turns green. Both vehicles can use their accelerator pedals to control their rate of acceleration and they both accelerate away in a nice sedate manner.
As I mentioned in a previous post, an Ioniq 5 (EV) weighs about 2000kg while a Rav4 (gas) weighs about 1700kg. The EV therefore weighs roughly 15% more. If both vehicles leave the line at the same rate of acceleration the torque output from the EV will need to be 15% higher.
a=t/(d*m)
That then takes us back to Newton’s Second Law and thus the longitudinal interaction force between the tire and pavement will be about 15% higher - which is not nothing, but let’s add some context.
Perspective
The coefficient of drag Cd for the Ioniq 5 is 0.288 vs 0.310 for the Rav4 - about 8% higher. The drag equation is
Fd = 1/2 r * u^2 * Cd*A
where r is the air density, u is velocity, and A is the reference area. In this case r and A are equal (well, mostly equal in the case of area) for our ICE and EV examples.
What this equation tells us is that at a given speed, the Rav4 requires 8% more driving force to overcome wind resistance. This isn’t just during the acceleration phase, but at all times.
It also shows us that drag forces go up with the square of speed. That means that if you increase your speed from 100 to 115km/h (15% increase), the drag forces go up by 32%.
So if we compare the EV to the ICE vehicle under cruising conditions, the friction forces between the tire and the pavement are HIGHER for the ICE vehicle in this example.
Even more than that, the impact of increasing speed dwarfs both the impact of mass and the impact of the coefficient of drag.
Summary
I haven’t come across a peer reviewed body of knowledge that compellingly argues that an EV and an ICE vehicle, driven similarly, will have substantially different rates of tire wear. Rather, speed, proper inflation, and road surface seem to be much more significant. The bulk of reports of accelerated tire wear come from journalists and influencers reviewing vehicles - groups who likely enjoy the acceleration that EVs are capable of, but don’t have to use.
