Initial trailer pulling report - 90D and Airstream 22ft Bambi Sport

[JimVandegriff]

Some final thoughts on our 1st adventure with X and Airstream:
We thoroughly enjoyed ourselves and our adventure. The X performed very well, towing and power not being at all a problem, and being a comfortable vehicle to tow with. Towing range varied from 110 miles on a full charge to 135 (projected). It is possible to drive longer distances if the supercharger network is set up in such a way as to be no more than 100 miles apart. Most charging was done at RV parks using the 50 amp electrical circuit (dialed down to about 30 amps in the X so that the other 30 amp circuit can be used as shore power for the trailer at the same time).
Careful planning is needed at each step of a trip. Planning parameters include elevation, weather (especially wind and rain which can seriously reduce range), supercharger or other charger availability on your planned route, RV park reservations and availability during your traveling time, supermarket availability, and speed you wish to travel. Another factor is planning for supercharger charging time and the need to possibly unhitch and rehitch the trailer and X.
Part of our mission was to introduce our X as an electric vehicle to other people. We spoke to people at every stop about the X and the Airstream, so planning time for that was important to us.
By the way, we enjoyed Kansas and the rest of our trip, but "there is no place like home" to quote Dorothy. We are already beginning to plan our next trip in the spring. Thanks for reading and if you have other questions, I'll do my best to answer here.
Unhooked at home after exactly 3 months on the road together:

 

[ohmman]

More data - mountain pass edition. Lookout mountain pass (4725 feet) was wild - I watched as our energy consumption rate skyrocketed as we ascended - it topped out at 1735 wh/m ( 1 3/4 KW per mile) near the top. We had just charged at the campground we stayed at and 20 miles later we had 35 miles of remaining charge at the top of the pass. Thank goodness and Tesla for good regenerative braking. We ended our travels in Missoula having gone 121.6 miles, using 73.4 KWh at 604 wh/m. We will be here for a few days visiting family, then it is onward through Montana, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, Utah, Nevada, and California. Data galore to come.

I'm curious, was that a bit of an incline given the elevation (4725 feet) and 1735 wh/m usage? What would you estimate the hill grade to be?

As I continue to vet out getting the identical Airstream that Jim and Illijana are pulling, I am dissecting this thread. This particular post is the most disconcerting. A full charge, driving 20 miles, and then having only 35 miles of charge remaining is obscene. I have to think Jim didn't get a full charge at the campground, or that I'm missing something. Regardless, I've taken the liberty of using this great tool to chart the elevation and get some stats on this climb. Ouch! That's one heck of a climb. Graphics attached, and please excuse my guesses at start and stop locations - I just subtracted 20 miles from Lookout Mountain Pass. Note also that the metrics are in.. well, metric.

 

[JimVandegriff]

As I continue to vet out getting the identical Airstream that Jim and Illijana are pulling, I am dissecting this thread. This particular post is the most disconcerting. A full charge, driving 20 miles, and then having only 35 miles of charge remaining is obscene. I have to think Jim didn't get a full charge at the campground, or that I'm missing something. Regardless, I've taken the liberty of using this great tool to chart the elevation and get some stats on this climb. Ouch! That's one heck of a climb. Graphics attached, and please excuse my guesses at start and stop locations - I just subtracted 20 miles from Lookout Mountain Pass. Note also that the metrics are in.. well, metric.

View attachment 204645 View attachment 204646

We started the day in Spokane, WA, and drove to Couer D'Alene, ID where we fully charged at the supercharger (because we had heard from Gary Guest that the climb was a bear), then tackled the Lookout Mountain climb. It really was shocking to see the rate of energy use per mile near the top, but the regenerative braking coming down was equally impressive. We spent the night in Osburn, ID at the Blue Anchor campground where we charged again. Plug in the locations of Couer D'Alene and Osburn for a more accurate representation of the route. We went from Osburn to Missoula the next day. I'll see if I can find my original calculations notebook. (ed. note - Found the original notes - 66.7 miles that day, using 660 wh/m in total). Remember, the 35 miles of charge left was at the very top of the pass, and based on the current stats the car had, and did not reflect the reality of going down on the other side of the pass, so as scary as it was to see, we now know that regen gets us lots of range back, and that calculations based on what we now know will ease our way in the future.
Illijana and I are doing a post-trip reflection about the locations we went through and the RV parks and superchargers we used. We are about 2/3rds done.
Thanks for that useful tool! It will really help with trip planning.

 

[ohmman]

We started the day in Spokane, WA, and drove to Couer D'Alene, ID where we fully charged at the supercharger (because we had heard that the climb was a bear), then tackled the Lookout Mountain climb. It really was shocking to see the rate of energy use per mile near the top, but the regenerative braking coming down was equally impressive. We spent the night in Osburn, ID at the Blue Anchor campground where we charged again. Plug in the locations of Couer D'Alene and Osburn for a more accurate representation of the route. We went from Osburn to Missoula the next day. I'll see if I can find my original calculations notebook.
Illijana and I are doing a post-trip reflection about the locations we went through and the RV parks and superchargers we used. We are about 2/3rds done.
Thanks for that useful tool!

Jim, I'm pretty sure it is the Osburn to Missoula trip that encompasses the Lookout Mountain climb, not the one prior. So really, the question would be more about your SOC leaving the Osburn campground. I can't imagine you left with anything less than 100%, so it just says something about that kind of grade. Perhaps 1000' of climb can affect range more severely if the grade is steeper.

 

[ecarfan]

Perhaps 1000' of climb can affect range more severely if the grade is steeper.

Now there is an interesting theoretical physics problem. Is amount of energy used to gain 1,000 ft on a road with a 5% grade the same as the amount of energy used to gain 1,000 ft on a road with a 10% grade? The vertical gain is the same on both roads but the linear distance travelled is greater on the 5% grade road. Since the energy used overcoming the vehicle's rolling resistance is likely the same on both roads (assuming identical pavement characteristics and weather and other factors) one might conclude it would take less energy to gain 1,000 ft on the steeper road, the opposite of what @ohmman postulated. However, the difference in linear distance covered over the two different roads is very small (visualize the hypotenuse of each triangle in an idealized drawing of the the two roads) so I think we can discount that factor.

I just can't see how a steeper grade would consume significantly more energy to gain elevation compared to a more moderate grade. As you drive up the hill you are expending energy which goes into increasing the potential energy of the vehicle. It seems that would be the primary factor influencing energy consumption. Given the fact that roads rarely exceed a 10% grade, it would seem that rolling resistance would not change much between a level road compared to the steepest roads one would likely encounter on paved, public highways (excluding non-public dirt roads in remote areas which might be even steeper and of course the road surface would be very different).

No doubt I am missing something here...

 

[vandacca]

Now there is an interesting theoretical physics problem. Is amount of energy used to gain 1,000 ft on a road with a 5% grade the same as the amount of energy used to gain 1,000 ft on a road with a 10% grade? The vertical gain is the same on both roads but the linear distance travelled is greater on the 5% grade road. Since the energy used overcoming the vehicle's rolling resistance is likely the same on both roads (assuming identical pavement characteristics and weather and other factors) one might conclude it would take less energy to gain 1,000 ft on the steeper road, the opposite of what @ohmman postulated. However, the difference in linear distance covered over the two different roads is very small (visualize the hypotenuse of each triangle in an idealized drawing of the the two roads) so I think we can discount that factor.

I just can't see how a steeper grade would consume significantly more energy to gain elevation compared to a more moderate grade. As you drive up the hill you are expending energy which goes into increasing the potential energy of the vehicle. It seems that would be the primary factor influencing energy consumption. Given the fact that roads rarely exceed a 10% grade, it would seem that rolling resistance would not change much between a level road compared to the steepest roads one would likely encounter on paved, public highways (excluding non-public dirt roads in remote areas which might be even steeper and of course the road surface would be very different).

No doubt I am missing something here...

Probably something related to lower efficiency at higher torque and/or lower efficiency at higher temperatures (due to motors working harder). It would easily surpass the slight gains in less rolling resistance.

 

[JimVandegriff]

Jim, I'm pretty sure it is the Osburn to Missoula trip that encompasses the Lookout Mountain climb, not the one prior. So really, the question would be more about your SOC leaving the Osburn campground. I can't imagine you left with anything less than 100%, so it just says something about that kind of grade. Perhaps 1000' of climb can affect range more severely if the grade is steeper.

Yep, you are correct about Lookout Mountain being between Osburn and Missoula. The really steep climb happened on the 4th of July pass (11% gradient on the app) which while lower, was much steeper in my recollection, and more energy intensive. It was between Couer D'Alene and Osburn. I wish I had taken better notes! We had a discussion yesterday about refining our note taking procedures for our next trip.

 

[ohmman]

Yep, you are correct about Lookout Mountain being between Osburn and Missoula. The really steep climb happened on the 4th of July pass which while lower, was much steeper in my recollection, and more energy intensive. It was between Couer D'Alene and Osburn. I wish I had taken better notes! We had a discussion yesterday about refining our note taking procedures for our next trip.

Thanks, Jim. I was just going by your posting, which claimed it was the Lookout Mountain. But maybe you mixed them up when you posted. Still, I'm concerned about 20 linear miles using up ~220 miles of range.

Probably something related to lower efficiency at higher torque and/or lower efficiency at higher temperatures (due to motors working harder). It would easily surpass the slight gains in less rolling resistance.

OK, you and @ecarfan have taken my comment and made a useful point. We need to take this into a new thread, which I've created.

 

[GSP]

Now there is an interesting theoretical physics problem. Is amount of energy used to gain 1,000 ft on a road with a 5% grade the same as the amount of energy used to gain 1,000 ft on a road with a 10% grade? The vertical gain is the same on both roads but the linear distance travelled is greater on the 5% grade road. Since the energy used overcoming the vehicle's rolling resistance is likely the same on both roads (assuming identical pavement characteristics and weather and other factors) one might conclude it would take less energy to gain 1,000 ft on the steeper road, the opposite of what @ohmman postulated. However, the difference in linear distance covered over the two different roads is very small (visualize the hypotenuse of each triangle in an idealized drawing of the the two roads) so I think we can discount that factor.

I just can't see how a steeper grade would consume significantly more energy to gain elevation compared to a more moderate grade. As you drive up the hill you are expending energy which goes into increasing the potential energy of the vehicle. It seems that would be the primary factor influencing energy consumption. Given the fact that roads rarely exceed a 10% grade, it would seem that rolling resistance would not change much between a level road compared to the steepest roads one would likely encounter on paved, public highways (excluding non-public dirt roads in remote areas which might be even steeper and of course the road surface would be very different).

No doubt I am missing something here...

ecarfan,

Here are my thoughts on the matter, FWIW:

Ascending the steeper grade at the same speed requires significantly more power (rate of energy use). This will result in more energy lost to heat in the motors, inverters, battery and high voltage cables and connections. This can explain the extra energy used.

However, the most alarming thing for the driver is not the kWh used to get to the peak, but the "miles range remaining" estimate. This estimate uses the very high rate of energy consumption to climb to the peak, and this rate is significantly higher for the steeper grade.

GSP

PS. I would like to thank Jim for posting his experiences here. What a great adventure. It was fun and informative to read.

PPS. It is a remarkable testament to the Model X powertrain design that it could handle this trailer at the speeds and grades that Jim drove, without ever needing to cut power to prevent overheating. Tesla has a great platform to make a capable pickup truck someday, when even higher capacity batteries are available.

 

[muleferg]

I ordered this hitch cover for my X from cafe press.

 

[ecarfan]

Ascending the steeper grade at the same speed requires significantly more power (rate of energy use). This will result in more energy lost to heat in the motors, inverters, battery and high voltage cables and connections. This can explain the extra energy used

@GSP thanks for your comments. I can understand how a steeper grade requires more power per linear unit of road distance to move the car/trailer mass uphill. And I can understand how using more power means generating more heat in the drivetrain (battery/cabling/inverter/motor). What I am unable to do is quantify that relationship and therefore I have no conception of how significant the increased motor power and drivetrain heat generation is compared to ascending a grade half as steep and therefore somewhat longer. There is an energy consumption difference between a 10% grade and a 5% grade, but I do not know the magnitude of that difference. It may be smaller than you envision or it may well be much larger than what I envision.

I do not have any long (as in over 5 miles or so to get a usable per mile average kWh figure) steep grades near my house that I could run tests on with my S. What we need is someone who lives near a multi-mile very steep grade (7-10%) and a multi-mile moderate grade (3-5%). At the bottom of each grade, starting with the same battery SOC, they could set one of the trip odometers to 0, go up the grade to the peak, and then they would have a kWh/mi figure for each grade. That would be very interesting information. If they were towing a trailer, all the better. Of course we would want the weather conditions to be basically the same during each run, and also want the car HVAC settings to be the same (and all windows closed, maintain the same speed, etc.).

However, the most alarming thing for the driver is not the kWh used to get to the peak, but the "miles range remaining" estimate. This estimate uses the very high rate of energy consumption to climb to the peak, and this rate is significantly higher for the steeper grade

Yes, but the car's Energy Prediction graph in the center display bases that estimate on what the car has used over the last several miles driven and doesn't know that the car is about to stop requiring such high levels of power at the peak and have an almost free ride downhill during which some energy will be added to the battery.

I am sure that in the future the energy graph will be tied into the onboard nav route so that the energy usage data during a steep uphill will not appear so alarming to the driver.

 

[ohmman]

@JimVandegriff and Illijana,

Just want to tell you that this thread, your data, and your experience have encouraged me to follow in your footsteps. We made the decision to purchase the same 22' Sport (2017 model) and finalized it today. They are doing some custom work to it over the next week but we should take delivery soon.

Thanks so much, and I look forward to providing similar detailed threads to the community!

 

[JimVandegriff]

@JimVandegriff and Illijana,

Just want to tell you that this thread, your data, and your experience have encouraged me to follow in your footsteps. We made the decision to purchase the same 22' Sport (2017 model) and finalized it today. They are doing some custom work to it over the next week but we should take delivery soon.

Thanks so much, and I look forward to providing similar detailed threads to the community!

That is terrific! The 2017 had some nice additions as well (door window, bed riser, dual sink). I'm looking forward to hearing your adventures! All the best to you and family in the fun to come. Jim and Illijana

 

[azbob]

Jim, Do you know what the Combined Gross Vehicle Weight is for the Model X? We know that the Model X can pull 5,000 lbs with 20 inch wheels. If the Model X weighs 4,500 lbs with zero passengers and cargo, then pulling a 4,500 lb airstream, would add up to 9,500 lbs. What would be nice to know is how much additional weight one can have for passengers and cargo in the Model X and not exceed the Gross Combined Vehicle and Trailer weight for the Model X.

 

[Lbkmxp100d]

Some final thoughts on our 1st adventure with X and Airstream:
We thoroughly enjoyed ourselves and our adventure. The X performed very well, towing and power not being at all a problem, and being a comfortable vehicle to tow with. Towing range varied from 110 miles on a full charge to 135 (projected). It is possible to drive longer distances if the supercharger network is set up in such a way as to be no more than 100 miles apart. Most charging was done at RV parks using the 50 amp electrical circuit (dialed down to about 30 amps in the X so that the other 30 amp circuit can be used as shore power for the trailer at the same time).
Careful planning is needed at each step of a trip. Planning parameters include elevation, weather (especially wind and rain which can seriously reduce range), supercharger or other charger availability on your planned route, RV park reservations and availability during your traveling time, supermarket availability, and speed you wish to travel. Another factor is planning for supercharger charging time and the need to possibly unhitch and rehitch the trailer and X.
Part of our mission was to introduce our X as an electric vehicle to other people. We spoke to people at every stop about the X and the Airstream, so planning time for that was important to us.
By the way, we enjoyed Kansas and the rest of our trip, but "there is no place like home" to quote Dorothy. We are already beginning to plan our next trip in the spring. Thanks for reading and if you have other questions, I'll do my best to answer here.
Unhooked at home after exactly 3 months on the road together:
View attachment 202995

I'm in the market for an Airstream and was curious to know where you got yours? I too will be towing with my X P100D and your info you provided on this forum is much appreciated!

 

[JimVandegriff]

I'm in the market for an Airstream and was curious to know where you got yours? I too will be towing with my X P100D and your info you provided on this forum is much appreciated!

Airstreams are sold at Airstream dealers, and at some independent dealers. You can check for dealers in your area at Airstream USA, Airstream Travel Trailer, Silver Bullet | Airstream., or find used Airstreams at Airstream Trailer Classifieds - Airstream Trailers For Sale. We got our Airstream Sport Bambi (22ft) at Bay Area Airstream which includes dealerships in Idaho, Oregon, and northern California. The best walk through videos I've found come from Colonial Airstream and you can get a sense of standard pricing there. The video walkthroughs are quite good. You can expect to pay about 15% less than msrp after negotiating. Colonial Airstream - Airstream Travel Trailer, Bambi, Flying Cloud, International Signature, Serenity, Classic Limited, Interstate, Sport. Let us know what you find!

 

[JimVandegriff]

Jim, Do you know what the Combined Gross Vehicle Weight is for the Model X? We know that the Model X can pull 5,000 lbs with 20 inch wheels. If the Model X weighs 4,500 lbs with zero passengers and cargo, then pulling a 4,500 lb airstream, would add up to 9,500 lbs. What would be nice to know is how much additional weight one can have for passengers and cargo in the Model X and not exceed the Gross Combined Vehicle and Trailer weight for the Model X.

I always assumed that our X weighs in at about 6500 lbs. I think we checked it once and it was below 6000, but don't remember exactly. Our fully loaded trailer weighed in at about 4100 lbs if I remember correctly, so total is in the 10,000 lb range plus or minus a few hundred. Does that help? Let me know if you need any other numbers. I can't guarantee I've got them, but maybe ohmman will chime in.

 

[ohmman]

I have the numbers for the X90D/20" wheels specifically. They differ based on model.

Curb Weight (empty): 5271lbs
GVWR (max loaded with passengers): 6768lbs.
Max towing capacity: 5000lbs.

The max towing capacity is calculated based on the owner not exceeding the GVWR. Therefore, the GCWR is 6768+5000 = 11,768 lbs for the Model X 90D. Note that approaching the GVWR will reduce the vehicle's tongue weight capacity. That is, if you load up your X (especially toward the back) with passengers and cargo, you should reduce the maximum 500lb tongue capacity accordingly. Some dealers will tell you that a weight distribution hitch will reduce the effective tongue weight, but my research has concluded it's a bad idea to make that reliance. The weight is still there. You're better off loading your trailer appropriately and using a tongue scale.

 

[ohmman]

@JimVandegriff and Illijana, did you use a tongue scale with your 22 Sport? My Sport, which is very lightly front loaded at the time with nothing under the bed and very little in the cabinets (but with a full fresh water tank) weighs in at just under 500 lbs - and that's before we count the weight distribution hitch that inserts into the receiver, and the cantilevering effects. One note is that I didn't have the trailer fully level when measuring the weight (it was nose down), so it may have been showing a higher effective weight than at level. The scale is +/- 2-3%.

Obviously I can backload the trailer behind the axles to better balance, but I was curious if you had paid attention to this. I'll spend a little more time balancing and weighing once I have it loaded for a trip. It would be easy enough to put the Sterilite containers in the bathroom with the door closed to offset the tongue.

Thanks.

 

[JimVandegriff]

@JimVandegriff and Illijana, did you use a tongue scale with your 22 Sport? My Sport, which is very lightly front loaded at the time with nothing under the bed and very little in the cabinets (but with a full fresh water tank) weighs in at just under 500 lbs - and that's before we count the weight distribution hitch that inserts into the receiver, and the cantilevering effects. One note is that I didn't have the trailer fully level when measuring the weight (it was nose down), so it may have been showing a higher effective weight than at level. The scale is +/- 2-3%.

Obviously I can backload the trailer behind the axles to better balance, but I was curious if you had paid attention to this. I'll spend a little more time balancing and weighing once I have it loaded for a trip. It would be easy enough to put the Sterilite containers in the bathroom with the door closed to offset the tongue.

Thanks.

We did not use a tongue scale (he said with head firmly in sand). We do use the bathroom shower for storage, and the main closet is behind the the axle of the trailer, so that helps. I'd be interested in hearing weight numbers with the hitch on and trailer and car fully loaded. How is trip planning going?