Range calculations and towing

[Hahne]

Does the range calculation in the vehicle take into consideration the payload weight in the vehicle? Is there there a place to enter the weight of a trailer so the estimate is more accurate when towing? In actual usage, do you find these estimates pretty close?

 

[bluenycom]

You also need to take into account the shape of the trailer. Aerodynamic makes a big difference the faster you go, maybe even more than the weight on a level road.

 

[jcanoe]

No, Tesla does not use the trailer weight or aerodynamics in estimating range. Based on videos of Tesla vehicles towing travel trailers a good estimate would be to cut your estimated range in half.

 

[OldEVDude]

You want to focus on energy consumption per mile. In a "clean" condition, my MYLR uses about 270 kWh/mile (averaging 75 mph). With 72,500kWh useable battery, that works out to a range of about 265 miles. (My bladder can't last that long, so it hasn't been a problem).

I had occasion in June to pull a 6x12 U-Haul trailer over 300 miles. To extend range, I held my speed at 55 mph to save energy, but consumption still jumped to about 430 kWh/mile. That dropped my range to about 170 miles. After I was on the Interstate for about 15 minutes, the car's energy consumption display seemed to adjust, and estimated remaining range fairly well. I suspect driving at 75mph would result in terrible mileage, so be aware.

That said, the trailer was not at maximum weight, although it was a "solid" trailer, meaning air resistance was rather high.

 

[Rocky_H]

After I was on the Interstate for about 15 minutes, the car's energy consumption display seemed to adjust, and estimated remaining range fairly well.

@Hahne This is a very helpful answer to your question. The main number that just shows the "rated miles" on the battery gauge isn't going to adjust to anything. It's based on a fixed efficiency constant from the EPA testing procedure, which is optimistic even in normal driving.

But if you pull up that Energy display on the screen, that is reading your actual consumption rate as you drive, and then projecting that recent usage into an estimated range remaining in real miles. And that one will be very close, because it's constantly recalculating from all of your actual use, including the trailer weight and drag and heating and everything.

 

[bruce4000]

With EVs having regen braking, on the highway, as long as your not exceeding the max tongue weight and overall max weight, range loss is mostly dependent on aerodynamics. I wish there was some epa rating for trailers and campers but tow vehicle shape also affects so doubt will ever see it. On you tube, Bjorne in Norway had some videos/numbers on towing different trailers which may give some idea.

 

[Hahne]

I had occasion in June to pull a 6x12 U-Haul trailer over 300 miles. To extend range, I held my speed at 55 mph to save energy, but consumption still jumped to about 430 kWh/mile. That dropped my range to about 170 miles. After I was on the Interstate for about 15 minutes, the car's energy consumption display seemed to adjust, and estimated remaining range fairly well. I suspect driving at 75mph would result in terrible mileage, so be aware.

It is very helpful to know that the range estimate recalculates based on how you drive.

Does the recommended supercharger location in navigation planning change to take the actual kWh/mileinto consideration?

 

[OldEVDude]

Alas, when you are using the navigation system to plan the trip it does not take into account the actual power consumption (because when you plan the trip it doesn’t know the load, how you’ll drive, etc). Which also means that as you drive the navigation does not recalculate your range based on actual consumption. (Sounds like a nice idea for a future software enhancement….). Instead you have to follow the energy trip screen.

On the outbound trip with the trailer I took a guess as to power consumption and planned the trip accordingly. On returning I was able to take the actual consumption and plan a little more intelligently.

 

[Johnny Vector]

Alas, when you are using the navigation system to plan the trip it does not take into account the actual power consumption (because when you plan the trip it doesn’t know the load, how you’ll drive, etc). Which also means that as you drive the navigation does not recalculate your range based on actual consumption. (Sounds like a nice idea for a future software enhancement….). Instead you have to follow the energy trip screen.

On the outbound trip with the trailer I took a guess as to power consumption and planned the trip accordingly. On returning I was able to take the actual consumption and plan a little more intelligently.

Are you sure? Because I've enjoyed watching the predicted arrival SOC in the nav increase as I drive along. You have to expand the directions panel to see the arrival SOC, and it updates pretty irregularly, but I've seen it go from 13% when I start driving to like 21% after 30 or 40 miles.

I think you're right about the initial estimate, though. That is, if you're on a long trip and you are charging, it doesn't use your consumption from the previous leg to estimate the efficiency on the upcoming leg. But once you start driving the next leg, it does update the predicted SOC at the next stop.

Now if it could use the cabin camera to check the size of my chai tea, and maybe notice how fast I drink it, and then use that info to predict how long before I need to stop...

 

[Hahne]

. if you're on a long trip and you are charging, it doesn't use your consumption from the previous leg to estimate the efficiency on the upcoming leg. But once you start driving the next leg, it does update the predicted SOC at the next stop....

When you are starting a trip, I understand that it could not know the weight of your payload/trailer and driving style. But after charging on a roadtrip, I would expect it to make an educated guess of range, assuming the same driving parameters. Otherwise it is really hard to know where you should plan to charge. Until chargers are as ubiquitous as gas stations, thus could easily leave someone stranded on a trip.

I would also expect estimated range to take into consideration the histoeical driving style associated with a particular driver profile.

 

[E-curb]

My real world experience, towing a flat utility trailer with a golf cart on it, my range drops by 60%. Weight is over 2,000 pounds, but as others have said, the aerodynamic drag is more significant than the extra weight.

And if you are going to need to charge on your trip, you need to figure out the logistics of getting your car's charge port close enough to the super charger. Worst case is you disconnect your trailer somewhere close to the charger, charge and then re-connect the trailer.