Are the Average Energy per mile metrics on the trip screen accurate?

[honor_the_driv]

I'm 5 days into having my 2023 AWD Model Y (est 279 mi range). Thus far I've never driven it more than 40 miles in a single day. I'll be taking a short road trip soon, ≈220 miles, and wanted to get a sense of the range I should expect before stopping to charge.

This morning I did a round trip of 25 miles.The trip screen recorded an average energy usage by 250 Wh/mi. A simplistic way to get a rough estimate for potential total range, based on those driving habits, should be to divide the size of the battery by the average energy usage per mile.

I have yet to see a confirmation on the Tesla site for the battery size but what I see online for Model Ys is 67.6 to 81 kWh. Assuming the lower figure of 67,600 Wh (67.6 kWh) then the math works out to 67,600 Wh / (250 Wh/m) = 270.4 mi. That is suspiciously close to the estimated range, according to Tesla. Everything I've read about Tesla's range numbers so far are that those numbers are vastly optimistic and basically never achievable in real-world usage.

So my question is.... are the average energy metrics on the trip screen somewhat accurate and usable for estimating range between legs of a trip, assuming fairly consistent driving behavior?

 

[jcanoe]

Yes. The Tesla Energy Screen will use recent driving data, i.e. past several weeks, for the vehicle when estimating arrival state of charge at the next waypoint/charging stop or at the planned destination. (If you purchase a used Tesla vehicle you should restore the factory settings so that the driving history is cleared.) The energy consumption and estimated arrival time and arrival battery state of charge remaining will be updated as you drive the route. If the Tesla Navigation System Route Planner determines that you won't be able to reach the next waypoint/charging stop at your current energy consumption the Tesla Model Y will display a warning notice to reduce your speed to Xx MPH or else add a charging stop.

Don't overly be concerned with battery size. It is estimated to be 78.x kWh usable for the 2023 Long Range Model Y with 2170 battery cells (this for a new battery pack). The lower value (67.6 kWh) is for the Austin built Tesla Model Y with the 4680 battery cells.

Range is usually not a factor as the Supercharger network in North America now has 2200+ locations and 12,000 Supercharger plugs. There is rarely a need to charge beyond 80% when using a Supercharger in order to reach the next waypoint/charging stop or your destination. Departing from your home with a 90% charge should be more than enough charge to reach the first charging location. Let the Tesla Navigation System Router Planner guide your charging stops and you will be fine. You can use A Better Route Planner (ABRP), on your phone or computer, for additional trip route charging planning.

Plan on stopping every 2 to 2.5 hours for a short, i.e. ~20 minute, Supercharger charging session. Plan on arriving at a Supercharger with less than 30% state of charge remaining and ending the charging session when the battery state of charge is no more than 80%. Always enter the desired Supercharger location in the Tesla Navigation System or when following a trip route. This will ensure the battery pack is fully preconditioned (to the optimal temperature for Supercharging) for the fastest charging session.

 

[honor_the_driv]

Well I asked more because if the trip screen's number of 250 Wh/mi is really an accurate measure of my energy usage for that trip then I might not even have to stop to charge when I go on my trip and still have a maybe 10% left when I get to my destination, assuming I charge to close to 100% before leaving.

There is a charger at the destination so arriving at ≈10% would not be a concern.


Granted, I have a small child, so we'd almost certainly have to stop during the drive anyway, but it would be nice to know the realistic possibilities.

 

[dakhlkt22]

Well I asked more because if the trip screen's number of 250 Wh/mi is really an accurate measure of my energy usage for that trip then I might not even have to stop to charge when I go on my trip and still have a maybe 10% left when I get to my destination, assuming I charge to close to 100% before leaving.

There is a charger at the destination so arriving at ≈10% would not be a concern.


Granted, I have a small child, so we'd almost certainly have to stop during the drive anyway, but it would be nice to know the realistic possibilities.

Instead of calculating it out myself using wh/mi, I would feel more confident using the Tesla navigation which will automatically including charging stops for you. Presumably Tesla's AI calculations are based on the real efficiency of your vehicle. I really like the way Tesla navigation tells you how much battery you are projected to have when you arrive at a SuperCharger. As you drive, you can keep your eye on that number to see if you are on track.

On our recent trip, Tesla navigation wanted me to do two charging stops. I just ignored the idea of a second charging session. When the car told me at the first supercharger that I could stop, I just kept charging. After some extra minutes of charging, the second charging stop was deleted from the trip it originally planned for me.

If you want to get comfortable in advance, you could just pop into the car and enter in your trip destination even though you're not leaving yet and have a look at the routing. It wouldn't be as accurate as same day routing but it'd give you an idea.

 

[jcanoe]

Well I asked more because if the trip screen's number of 250 Wh/mi is really an accurate measure of my energy usage for that trip then I might not even have to stop to charge when I go on my trip and still have a maybe 10% left when I get to my destination, assuming I charge to close to 100% before leaving.

There is a charger at the destination so arriving at ≈10% would not be a concern.


Granted, I have a small child, so we'd almost certainly have to stop during the drive anyway, but it would be nice to know the realistic possibilities.

You will find that road trips are less fatiguing if you stop, take a 20 minute break, while using a Supercharger once every ~2 to 2.5 hours. Be sure that you have a valid credit card or debit card linked to your Tesla account so that you can use the Supercharger network. Seek out Supercharger locations with casual dining or fast food choices within walking distance. If there are multiple Supercharger locations within a short distance you might want to choose the one that is typically less busy during the window when you will be traveling.

The Tesla Route Planner will factor in elevation changes when estimating consumption. Unplanned traffic/detours can increase consumption as can cross winds and changing weather conditions. Every Tesla owner will find their own comfort level for battery reserve, i.e. 10%. Better to arrive with a comfortable level of charge remaining than too little for comfort.

 

[Rocky_H]

So my question is.... are the average energy metrics on the trip screen somewhat accurate and usable for estimating range between legs of a trip, assuming fairly consistent driving behavior?

No, not the way you're doing it. You've been puttering around town at low speeds and are looking at that efficiency number. But what you are talking about is can you extrapolate that to a long highway trip? Well, what you're going to do is get on the entrance ramp of the highway, zoom it up to 81 mph and peg your cruise control there, and then will be dismayed that the high speed and high wind resistance doesn't match the great efficiency you were getting when you were going to the grocery store in town. It's two different kinds (speeds) of driving, and the efficiency won't be the same.

Everything I've read about Tesla's range numbers so far are that those numbers are vastly optimistic and basically never achievable in real-world usage.

There is a lot of background context to that. The EPA for gas cars has only one testing procedure, as it should be. For electric cars, they offer manufacturers the choice of two vastly different methods, which most of the public isn't even aware of. One method is to do the specific five cycle testing procedure. That is what Tesla does, and highway speeds are going to be worse than that mild EPA testing cycle. The other method is this weird thing of making up some sandbagging lowball reduced number. That's what the other manufacturers do, so they usually beat that lowballed number in real world tests.

So Tesla is closer to EPA numbers but below them. Other brands are wildly off from their made-up number, but above.

 

[honor_the_driv]

No, not the way you're doing it. You've been puttering around town at low speeds and are looking at that efficiency number. But what you are talking about is can you extrapolate that to a long highway trip?

For the 25 mile round trip I'm referring to it was mostly highway miles, 20.2 miles of highway traffic to be exact.

 

[jcanoe]

You may have the energy advantage of decreasing elevation or a decent tailwind when outbound or inbound. That would be the ideal time to test whether you can make the entire trip without stopping to charge at least once.

Try ABRP (it's free for the standard version) to learn what charging stops ABRP recommends for the trip route.

 

[Art84]

Your Wh/mile will significantly depend on your cruising speed.
So, is the Tesla measurement accurate? Yes
Will you have the same consumption on a road trip? Not necessarily. It will depend on speed, wind, and elevation.

 

[jcanoe]

As many have experienced this summer, temperatures in the 90s or higher will result in significantly higher energy consumption (Wh/mile) than would be experienced if driving with temperatures in the 70s. Daytime energy consumption while the sun is high in the sky will be even higher (a good ceramic tint job on the glass will help reduce the daytime heat load on the Tesla Model Y's climate control system.)

 

[E90alex]

The energy usage/trip meter only accounts for energy used while driving in the efficiency calculation.

 

[honor_the_driv]

The energy usage/trip meter only accounts for energy used while driving in the efficiency calculation.

Do you mean that any energy used while stopped at a red light is not counted towards that calculation?

 

[E90alex]

Do you mean that any energy used while stopped at a red light is not counted towards that calculation?

Energy used while the vehicle is parked is not counted.

 

[jcanoe]

Do you mean that any energy used while stopped at a red light is not counted towards that calculation?

No, not while at a stop light. Energy consumption while preconditioning is not included in the driving efficiency or while parked with the climate control running. The Climate Control system will consume perhaps ~2% of the battery per hour and will not be included. The Energy Screen now includes a tab for energy consumption while parked for functions such as Sentry mode, Summon Standby and Cabin Overheat Protection.

 

[BitJam]

Granted, I have a small child, so we'd almost certainly have to stop during the drive anyway, but it would be nice to know the realistic possibilities.

I suggest you err on the side of caution for your first few road trips. The car should do this for you automatically in the navigation screen. With a few trips under your belt you will have a much better idea of what range you will get than any of us here could give you.

 

[honor_the_driv]

You've been puttering around town at low speeds and are looking at that efficiency number.

So today I did look at the trip efficiency numbers while I was puttering around (lol) on city streets and I see that before I got on the highway the number was around 320Wh/mi.

 

[Rocky_H]

So today I did look at the trip efficiency numbers while I was puttering around (lol) on city streets and I see that before I got on the highway the number was around 320Wh/mi.

I forgot to mention that there is kind of a happy medium about this. For really short drives that have a lot of heating or cooling, the energy consumption does start out really high, because of it doing some heavy climate control. The other day, I backed out of my garage, stopped in the driveway while waiting to make sure my garage door closed all the way, and then finished backing out into the street to start driving. My wh/mile showed over 1,000.

So yes, sometimes the really short 5-10 minute drives do look pretty high on consumption. When drives are a little longer, the cabin gets to temp, and the energy usage settles down. But then at the other end is if people are just doing really fast speeds on the highway, then it can be high again in that condition.

 

[honor_the_driv]

Now that I got my wall charger connected in the app I have a little bit more information on this topic. Check here- Comparing cost per mile using total energy from trip screen metrics vs wall charger metrics and compared with ICE.