Studio711.com – Ben Martens

Welcome to another Tesla Tuesday!

We just crossed 40,000 miles on our 2022 Model Y after almost exactly two years of ownership. I’ll use a similar format to the 20,000 mile review.

Cost

While I’ve always been interested in EVs as technology, I was never willing to pay extra to get it. The key reason we jumped into the Tesla was because I believed we could break even on the cost. I have a detailed data pipeline set up to track everything I can about our costs. By tracking the prices of gas stations around my home daily and comparing it to how many miles we drove each day, I can calculate that we would have spent $8,047 on gas using the Ford Escape that we would likely have purchased instead of the Model Y. Instead, we have spent $1,722 on electricity for charging.

• 91% of the charging was done at home for $0.11/kWh
• 7% of the charging was done at super chargers on road trips for around $0.40-0.45/kWH
• 2% of the charging was done at free chargers like Airbnb’s

Based on the prices of the Model Y and the Escape when we bought our car, I estimated that we would need to save $18,000 to break even. The bulk of that savings is going to come from not buying gas which means that the more gas costs, the faster we break even. Here’s a chart showing the daily gas prices for the half dozen stations closest to our house (which includes a Costo gas station.)

Based on the data so far, I estimate that we’ll save about $15,000 in gas in the first 100k miles if gas prices stay in the same range.

A big chunk of the rest of the savings should come from reduced operating and service costs. There are no oil changes or brake replacements and there are a lot fewer moving parts to wear out. Up until a few weeks ago, we hadn’t bought anything more than windshield washer fluid for the car. But we did buy tires so that was a major purchase. As a quick update to that tire post, the new tires have been working out well. Efficiency was a major part of my research and while it’s difficult to tell over just the first couple thousand miles, I’m not seeing anything that indicates a measurable decrease in efficiency.

I do think that state registration fees are hurting us more than I expected. Our area keeps voting in more and more taxes so, for example, we spent $939 to register the Tesla in 2023. A large portion of that price is based on how much the state says your car is worth so having the extra value in the car does mean it’s $100-200 more/year than Escape would have been.

A major repair bill with the Tesla could change everything, but at this point we’re on track to “break even” even with pessimistic calculations. For example, my $18,000 goal assumes that we the Tesla and the Ford would have lasted the same number of miles and would have sold for the same amount of money. I’m hoping our Tesla will last longer than the Ford would have and I also expect it to sell for significantly more given the longevity of EVs.

Stats

I’m not going to redo all the stats that I did in the 20k update, but I’ll share a new stat: Battery Health. The TeslaMate software which gives me so much of the data I use to track these costs has a new calculation for battery health. It tries to estimate the actual capacity of your battery against the capacity it had when it shipped. This is not an exact measurement, but it shows that we’re right on track with the expected degradation curve. After 40,000 miles we’ve lost 3.6% of our usable capacity. I did notice during our trip to Utah that there was more degradation, but the numbers have bounced back. I’m not sure if that’s something due to us doing lots of rapid charging or driving in extreme heat at high speeds, but it doesn’t look like anything to worry about. Tesla says that batteries lose about 5% in the first 25,000 miles on their way to losing 12% over the first 200,000 miles.

Experience

The best way to explain our thoughts about this car is that if something happened to it today, I’d pull out my phone and buy another one without much thought. We love this car! Yes, it’s a bit annoying looking like so many other cars on the road, but other than that, it’s a fantastic car to own and drive. We drive this almost exclusively now and I must keep track of the last time I drove the truck so it doesn’t sit too long.

I’ve probably said this before, but I underestimated how wonderful it is to walk out to a “full” car every morning. I always thought that filling up with gas didn’t take that much time so it wasn’t a big deal, but you know what takes even less time? Doing nothing! We pull into the garage, plug in the car and that’s it. It’s full every morning.

I also love the “golf cart” nature of the car. I just hop in and go. There’s no consideration about whether I’ve run the gasoline engine long enough to recharge the 12v battery, burn off the moisture I’m generating in the exhaust system, get all the engine parts fully lubricated, etc.

Consluion

The EV market has changed a lot since we bought our car. The Model Y is now the best selling car of any kind on the planet. It sold 1.23 million units in 2023 beating out things like the Corolla and the Rav4. Not only that, but it was an increase of 66% over the previous year. Tesla factory capacity continues to expand, but estimates for 2024 are all over the place as they are seeing slowdowns like (but smaller than) the rest of the auto industry. 1 in every 12 cars sold in the US is full battery electric. Furthermore, prices on the Model Y have decreased significantly since we purchased and there are federal tax credits at play too. At this point, we love the car so much we’d probably pay a premium to get it, but it’s nice to know that the EV/gas comparison will be more lopsided in the EV’s favor. And it’s even nicer to know, that given our flawless track record with the car so far, we hopefully have a ton of miles left before we start thinking about the next car.

Welcome to another Tesla Tuesday!

After almost 40,000 miles, the time has come to break the streak of spending $0 on service and maintenance (other than windshield washer fluid.) We’re probably replacing the tires a tad bit early, but they’re down to under 5/32″ in some places and at that point the tire shops stop doing repairs, etc. And since I regularly watch my wife and child drive off in the car, I feel better knowing they can stop quickly when they need to. 40,000 miles seems light to me for tire wear, but reading experiences from other users, it sounds like we did average/well on the stock tires. The cars are heavier and very sporty so it’s easy to burn through the performance tires.

Shopping for tires on our Tesla Model Y was an interesting experience. For example, I’ve never really considered rolling resistance of a tire before. Sure I know that some tires are marketed as more efficient than others, but since Teslas have such detailed economy measurements, I was able to find specific percentage differences in various tires. The challenge is that those measurements were mostly self-reported and varied widely in believability.

The second surprise was being reminded that we are effectively drive a sports car. It can do 0-60 in 4.7 seconds (or 4.2 if you swipe your credit card) and those tires are more expensive than what we bought for our Escape or Impreza.

The third surprise was just how much prices have increased since we last purchased tires in 2019. As I was shopping, I kept getting sticker shock at the total installed price. I got the idea to look up our receipt from 2019, find those exact same tires, and then compare the price. It turns out that the same set of tires from 2019 would have cost 27% more if we bought them now. So add that to the fact that these sportier tires were more expensive than the previous tires (an extra ~$90/tire) and that explains the sticker shock. I did check out Costco and was initially going to use them, but I ended up picking a tire that they didn’t offer. I found their tire prices similar but their installation and warranty was much cheaper.

In the end, I chose the Hankook iON evo SUV tires. They’re less performant than other popular options but offer longer tread life. I also got an alignment done because the initial tires were more worn on the inside than on the outside.

Time will tell how well these new tires hold up. It will come as no surprise to you that I was have an absurd amount of data to eventually compare their efficiency with the stock tires.

Welcome to another Tesla Tuesday! Maybe this is more of “EV Tuesday” but we’ll go with it.

Let’s talk about energy efficiency. We know that 30-40mpg is good for an ICE (internal combustion engine) vehicle. But how good is it when you consider all the available energy in the gasoline? The EPA says that a gallon of gasoline is equal to 33.7 kWh. That’s a huge amount of power but the engine only converts 25-30% of that into useful energy. The vast majority of the energy in gasoline is lost to heat.

To put that amount of energy into perspective, there’s theoretically enough energy in a gallon of gasoline to power our house (minus EV charging) for 1.5 days. When full, my F150 has almost a megawatt of power in the gas tank!

EVs on the other hand are more like 80-90% efficient. That can vary more widely though because, for example, in cold weather, heat isn’t free like it is in an ICE vehicle, so you have to use extra energy to generate heat. In an ICE vehicle you’re generating way too much heat year-round whether you want it or not.

Our Model Y LR is one of the most efficient EVs you can buy, and over the first 37,000 miles, it has averaged 278 Wh/mi (Watt hours per mile) or 3.59 miles/kWh. With the energy in one gallon of gas, it could go 121 miles.

This is exactly how the EPA generates their MPGe metric. It’s a bit of a silly calculation because you’re never going to build a car that can extract 33.7 kWh from a gallon of gasoline, but I think it is useful to understand how all those calculations work. And when you hear about how efficient a particular car is, remember that 70% of the energy it’s consuming is lost as a byproduct.

Welcome to another Tesla Tuesday!

The Tesla Cybertruck was released last week. It was announced all the way back in 2019 and now customers are finally taking deliveries. Let’s start with the positives…

The truck is an incredible feat of engineering. The AWD version does 0-60mph in 4.1 seconds and the “Cyberbeast” model does it in just 2.6 seconds. It does all that while having almost as much payload and towing capacity as my maxed-out internal combustion F150. As a visual to help explain how wild it is to cover both ends of the speed/towing spectrum, Tesla released this video of a Porsche losing a drag race to a Cybertruck… while the Cybertruck is also towing the same Porsche model.

There’s a video showing it in winning handily in a pulling competition against other EV trucks and a diesel F350. There’s also a video of the truck being “bulletproof” or at least bullet resistant. During development it was claimed that the truck would also be able to cross open water though I haven’t seen that independently tested yet.

So yes, it’s a technological marvel, but (and this is a big but)… yuck. It looks like a Pontiac Aztec had a baby with a kindergartener’s drawing of a truck. Teslas have extremely low coeffecients of drag and I’m sure that factored into the design, but still, I know that design is subjective, but I have zero interest in driving this eyesore.

When it was announced four years ago, I disliked it so much that I worried it would sink the whole company. Now we’re in a world where Tesla is probably going to claim the title of best selling vehicle on the planet of 2024. They will probably be ok even if the Cybertruck is a flop.

But will it be a flop? I doubt it. It might level out to be the lowest selling of their models after the initial hype, but I think they’ll sell enough of them to cover their development costs. Tesla incite a fan reaction only seen in companies like Apple. They can make anything they want and people will line up to buy it and rave about how great it is.

If I was replacing my internal combustion F150 today, I’d probably end up buying another gas truck. Rivian is good but their trucks are small for what I want. The electric F150 is intersting but I don’t trust the traditional manufacturers to make a good EV or back it up with a good ownership experience. We’ll get to a point where big trucks make sense as EVs, but I think today the best we can do is smaller trucks like the Rivian R1T.

These Tesla Tuesday posts usually talk about experiences with our Model Y and reasons why I’m happy with our decision. Tesla has the highest brand loyalty, but that doesn’t mean I recommend them to everyone or that I’d buy one myself in every situation. So who would I NOT recommend get an electric car?

1. If you live in an apartment, it’s unlikely that you’ll have a lot of charging options. Landlords are quickly realizing the importance of this amenity, but if I couldn’t charge where I normally park, that would remove a lot of the convenience for me. Even if the complex had a few chargers that people could share, I still probably wouldn’t go for it. I love coming home, plugging in the car, and then ignoring it until the morning when I walk out to a full charge.
2. If you have expensive electricity, it can change the math a lot. We pay $0.11/kWh hour here in the Seattle area, but in New Hampshire it’s $0.29/kWh! That’s getting close to Supercharger rates which are around $0.45-0.55/kWh. While all of those are still a lot cheaper than gas, it’s a wide range and needs to be part of your math if you’re doing this to save money. Then again, California has the most expensive electricity in the country but they’re also gaga for electric cars so there are more factors at play than just electricity costs.
3. If you get a new phone and spend the next six months grumbling about how everything changed, this probably isn’t for you. Electric cars usually get the fanciest new tech.
4. If you’re thinking about getting anything other than a Tesla, I wouldn’t recommend it unless you’re literally never going to take it on a trip that would require you to charge away from home. The non-Tesla charging networks are unbelievably horrible and I wouldn’t take a road trip if I had to rely on them. If you think I’m exaggerating, watch this fantastic comparison video or the many videos like it. Once all the non-Tesla muggles can charge at Superchargers, this becomes a non-issue, but then we’ll have to see what kind of crowding problems we have and see which of the other companies die off in the shakeout.
5. If you hate electric vehicles because… just because, then obviously I wouldn’t even be talking about this to you. Multiple times, even in this area, I’ve had some truck get in front of me and purposely “roll coal” to cover me in exhaust. Maybe they still wouldn’t want one if they had more info, but so many people blow off all EVs due to talking points from 24-hour cable news that simply aren’t true.
6. If you’re an expert car mechanic and you enjoy the work, there won’t be much that you can do on your EV. Being able to do most/all of your own car work also changes the math when considering how much an EV could save you.
7. If you drive more than 200 miles a day, you probably wouldn’t want an EV. I wrote a long post about choosing an EV with enough range, but the takeaway was to consider the high end of your common daily use case and then multiply that mileage by 1.5 or 2 to get the target EPA range to have stress free drives in all conditions.
8. If you take a lot of road trips and you don’t want to do any extra planning, an EV is probably not for you. While the car will tell you exactly where to stop and for how long, our trips go a lot smoother when I have tweaked that plan a bit for stops with good bathrooms, restaurants, etc. A long road trip feels like hopping between islands so there’s not a ton of flexibility if you’re trying to be efficient with your time.
9. If you’re going to do a lot of towing or hauling, a gas/diesel truck is still your best bet. Rivian makes an electric truck and Tesla has something sort of truck shaped coming out soon, but despite what the marketing materials say, you’re not going to be asking a front-end loader to dump a yard of gravel in the back. And even if you could tow your camper with it, you’re going to stop so often for charging (and you’ll have to unhook every time) that it’s silly.

One thing that’s not on this list is “if you don’t live close to a charging station…” The area within 75-100 miles of my house is the area where I care least about charging stations. In fact, I think that living far from a charger could be a good reason to get an EV because you’re probably live away from a city and getting anything (including gas) requires a significant amount of time. Instead, you could wake up every morning to a full charge. The only time I care about public stations is when I’m on a long road trip somewhere.

As I wrap this up, my text editor is complaining about all the uses of “probably” in this post, but I’m going to leave them in because there really are a lot of factors. However, I do think that the list of reasons to not get an EV is shrinking as the years go by. Millions of people are making the switch, but it will take time for to cover everyone’s unique scenario.

Welcome to another Tesla Tuesday!

As I’ve explained before, we jumped into a Model Y because my math convinced me that we’d at least break even when compared to the gas powered Ford Escape that we would have bought instead. That required us to save about $20,000 over the first 100,000 miles. All my calculations were done with gas prices at $3.50 and since they’ve been so much higher, our little experiment is working out quite well. We’re on track to save more than $16,000 in gas alone so if prices keep going up, we might make most of that $20,000 savings in fuel prices alone without even considering lower service costs and higher resale value.

Here’s the kicker: Our same Model Y now costs $8500 less! Plus some buyers will be elligible for a $7500 federal tax credit for a potential savings of $16,000 over what we bought. This means that the “will it save me money” decision is a no-brainer now. Obviously there are plenty of other factors that go into whether and EV fits your situation, but cost isn’t one of them if you’re comparing against other similar new cars.

The average price of a car sold in the US today is $48,000. A Model 3 starts at $38,990 and the Model Y starts at $43,990. The Long Range Model Y that we have starts at $48,490 which is just over the average price. All of these numbers are without the potential $7500 tax credit too. The chart below shows the delta between the Model 3 and Model Y compared to the average new car purchase price. (We got our Model Y price locked in around October of 2021.)

Priced used to be a sticking point when getting people into an EV because you had to pay up front and trust that the savings would come. Now we’re moving into a world where they compete on sticker price and THEN you get bonus savings on top of that over the life of the car.

Cars in general are still expensive and there are easy ways to spend way less than the average US car price by fixing the car you have already, buying a used car, or buying a lower priced new model. There’s still a gap in good EV options towards the lower end of the price spectrum, but the way things are going, that will get filled too. Lower priced cars will be important as countries inch closer to the mandated cutoffs for sales of gas vehicles. The chart below (via notateslaapp.com) shows when various areas are planning to change. It’s notable that nobody has fully hit their dates yet and these do get pushed back so we’ll see if/when we fully get there.

While it’s fun to see more people agreeing with the choice that we made, the bulk of my enjoyment comes from watching our “total savings calculator” spitting out bigger and bigger numbers while we bop around in a car that’s fun to drive with almost zero maintenance.

Now if you’ll excuse me, after 30,000 miles, we’ve had our first part in need of replacement: wiper blades.

For this Tesla Tuesday, I’m going to talk about taking a road trip that wasn’t in a Tesla!

Back in June we took a ~2500-mile road trip to Moab, UT in our Model Y and I did a full writeup about the experience. Recently, due to some unforeseen circumstances, we ended up driving to northeast Montana, and given the complete lack of charging infrastructure in that area, we took our F150 on the ~2000-mile trip. We spent two days getting out there and two days coming back. This was a rare opportunity to take two multi-day road trips in very different vehicles. So how did the F150 fare after our experience with the Model Y?

If you’re not familiar with northeast Montana, you should know that it’s extremely difficult to get to. An Oxford University study listed Glasgow, MT (our destination) as the hardest city in the United States and they have proudly adopted the “official middle of nowhere” slogan. Glasgow has a population of 3300 people making it the 23rd largest municipality in Montana. The closest city with at least that population is Lewiston, MT 200 miles away. The interstate doesn’t go anywhere near Glasgow. About half of the trip is on two lane highways. The train is a viable way to get from Seattle to Glasgow, but given the rules about Amtrak having to cede right of way to freight trains, your 20-30 hour scheduled train ride might be doubled. When an electric vehicle did venture into Montana away from the interstate, it ended up on the front page of the local paper. Thankfully we still have one foot in the world of internal combustion engines and the truck makes a great road trip vehicle.

Pros of driving the truck on a long road trip:

• Gas stations are everywhere. While there are long stretches of road with no gas on this route, it was easy to find one whenever we needed it.
• We could drive over 400 miles without refueling. This meant we had the option for more bathroom-only stops at rest areas. While the Model Y has a theoretical range of ~330 miles, I rarely planned anything more than 200 between charges given the relative lack of charging infrastructure.
• There was tons of room to carry our all our gear. We even threw a full size cooler in the back to keep snacks and lunches cool. We ate breakfast and lunch in the car on all our travel days which sped up the trip and saved us money.
• There is more room in the cab for us to have things like pillows and snacks.
• When we drove the Tesla to Moab, I would plan on getting to the midway stopping point hotel with a low battery and then while Tyla and Elijah swam in the pool, I’d go out to charge again. One night with the truck I did go out to fill up the tank but that was much faster than putting a big charge on the battery.
• It’s nice stopping at travel plazas where we can wash the windows, use the bathroom, and get some snacks all in the same spot.
• It was nice to blend in when we were in northeast Montana. A Tesla would have stuck out like I was Elton John in a sequin jacket.

Cons of driving the truck on a long road trip:

• Gas is expensive! Montana has significantly cheaper gas than Washington, but we still spent over $400 on gas alone. We averaged 19.8mpg on the way out and 19.1mpg on the way back due to a major headwind for the first ~5 hours of our trip. If we could have used chargers on the way, we would have only paid around $150 in charging fees.
• You’ll never believe this, but I had to manually steer the truck! What nonsense is this? Joking aside, I did miss the autopilot features of the Tesla.
• The Model Y is AWD and the truck is RWD. It does have four wheel drive but I don’t think it would be a good idea to leave that on for hours on the highway at high speeds. The AWD system gives me a lot more confidence especially on windy, wet roads.
• While the truck does have Android Auto, it means that I have to leave my phone plugged in to the car all the time. Sometimes when everyone else is sleeping or listening to their own thing, I like to pop in one headphone and listen to a podcast. I can’t do that without disconnecting Android Auto which means we don’t get traffic alerts and nobody else can listen to music. In the Tesla, the default maps are great and we have Spotify built into the car.
• The truck doesn’t have automatic climate control so I kept having to futz with the temperature controls.

But how about our travel speed? Did we get there faster since we didn’t have to stop to charge? I kept a detailed log on the way out so I could analyze things. Our average overall trip speed with the Tesla was almost identical to the truck with the truck being a few mph faster on our return trip. We made a total of 5 stops (plus our overnight stop) that averaged about 9 minutes each. The distance between the stops is about the same as if we had needed to charge, but we saved time by not having to charge. Most charging stops are 10-20 minutes so some of the stops were ~10 minutes faster than they would have been in an electric car. Your results may vary depending on how much of an iron bladder your occupants have.

So which vehicle will we take on the next trip? The Tesla. It’s not much of a contest. Nothing on the “pro” list for the truck is worth the extra price of gas, and the Tesla has those other items in its favor too. The only sticking point is, like the Montana trip, if charging will be hard. Situations like that are already rare, and they will be decreasing more over the next 5-10 years as the US standardizes on the Tesla charging connector and more charging stations get built both for fast charging and for overnight charging.

I live in a bubble of the highest per-capita EV ownership in the country. This trip was a good reminder of the huge amount of land that the EV infrastructure needs to cover and the diversity of people that it needs to win over. All of that will take time, so for now I’m sticking by my general statement that an EV can save a lot of people money today, but I’d be hesitant to recommend one to a single car family in most cases.

EV batteries are made up of many lithium-ion cells. Lithium is light and it can store a lot of energy which is a great combination for an electric car. However, extracting lithium from the ground requires a lot of water, energy, and chemicals and a lot of the world’s lithium is found in places that are already very dry. There are additional chemicals like cobalt, nickel, manganese, and aluminum which have their own problems including human rights issues.

So these batteries are full of nasty materials. Aren’t we just trading one fossil fuel (oil) for these other limited resources? The difference is that when you burn gas, it’s gone. When you use up an EV battery, there’s still a future for it.

First, EV batteries might not be suitable for the high demands of an electric car anymore, but they might be plenty for a lower drain application such as providing backup power for your house.

Second, EV batteries are incredibly recyclable. Estimates vary but around 95% of the material in an EV battery (and in any lithium battery from your cell phone, power tools, etc.) can be reclaimed through recycling. Recycling also releases fewer greenhouse gases than mining new minerals.

The current challenge is that recycling is expensive, but today the raw materials are abundant, and mining can roughly keep up with the demand, but the economics will change in the future as materials are harder to find, the demand for new batteries increases, and more EV batteries are nearing the ends of their lives. Additionally, some of the recent economic incentives for US battery production can be applied to EV battery recycling as well.

So yes, EV batteries are bad for the environment, but we should be able to keep reusing the materials that are being mined. And just because this process is messy doesn’t mean it’s worse than what is happening with gasoline today. The process of extracting oil, refining it, and burning gas is plenty nasty but comparing the two is beyond the scope of this post.

If you want to see this in action, check out this short YouTube video walkthrough of a battery recycling plant in Arizona, or check out the links below it for more reading materials:

https://www.caranddriver.com/features/a44022888/electric-car-battery-recycling/

https://www.bbc.com/future/article/20220105-lithium-batteries-big-unanswered-question

https://www.motortrend.com/features/ev-battery-recycling/

Welcome to another Tesla Tuesday!

We recently put 2500 miles on our Tesla Model Y and the road trip was a great experience. However, there was one stretch where I had some range anxiety for the first time. We left Twin Falls, ID with 82% charge which should have been enough to get us into Meridian, ID with 25% remaining. However, as we set out, our range was decreasing rapidly, and I was predicting that we’d get there with around 10-15% remaining. That’s still plenty of buffer, but it was disconcerting. I say this not to scare anyone off of EV’s but to make sure I’m not all roses and butterflies when I talk about driving one. I haven’t been able to figure out exactly what happened, but I suspect a combination of the following based on the minute-by-minute data that was logged from the car.

• It was HOT. Temperatures were between 99 and 104 on that stretch of the trip. HVAC can consume quite a bit of battery when it’s that hot.
• The speed limit was 80mph and I had the cruise set at 85mph. More on speed’s impact on efficiency later.
• We were driving into a headwind.
• Traffic was heavy-ish so there was a lot of slowing down and speeding up.

I expect the car’s estimation to take all these things into account, but something was definitely off. About 5 miles out from the supercharger in Boise, we spotted a Tesla with lights flashing going about 60mph trying to conserve energy and I assume they hit the same issue but didn’t notice it soon enough. My guess is that our trips were flagged by the engineers at Tesla and hopefully our experience will help improve their estimation models.

For my part, I decided early on to back off my speed and set the cruise at 78mph. This felt about as slow as I could go without being an annoying rock in the stream. That quickly helped to stabilize the estimate. Click on the link below to see all the charts from this stretch of the trip.

We made it with no trouble, but it was the first time that I had thought about what would happen if we didn’t make it. Some stretches of these roads also had signs about “no gas for X miles” but it’s easier to bring a gas can to your car than it is to bring your car to a charger.

I do think it’s interesting how much easier it is to calculate the exact impact of driving at different speeds and heats. When we cruise at 85mph, we were using 360-380 watts per mile but when we cruise at 65 it’s more like 250-270 watts per mile. That’s a ~40% increase in energy usage for an extra 20mph. This same thing happens in a gas-powered car too, but with a bigger tank and less data, you don’t always notice it as easily.

While TeslaMate does show me average efficiency by temperature, it doesn’t have a dashboard for efficiency by speed. It’s tricky to calculate because of all the various factors at play (temperature, elevation, traffic impact, driving style, etc), but if we take a naive approach and look at average efficiency in kWh based on average speed in mph for an entire trip segment, it looks like the chart below. Take this with a grain of salt because as I mentioned, this is a very rough estimate. I would expect an exponentially increasing line. Below about 35mph, there’s not a lot of data since I only used trips of at least 20 miles and I don’t often drive that far that slowly.

With a gas car, your efficiency peaks around 45mph and at slow speeds, you waste a lot of extra energy, but with an electric car, you can go almost as slow as you want and keep using less energy. However, at high speeds, they act similarly: drag increases with the square of speed. Driving a car with a very low coefficient of drag does help, you’re still bound by the laws of physics.