Towing with a Tesla

Towing a camper trailer with an electric vehicle is a relatively new phenomenon. The Tesla Model X is the first EV that I am aware of to be offered with a factory installed towing package option that includes a 2” hitch capable of towing a camper trailer with a weight up to 5,000 lbs and a tongue weight not to exceed 500 lbs (with the stock 20” tires, less with the optional 22”). The lightweight 1,700 lb (empty) Safari Condo Alto that I tow is well below those parameters.

I had never towed anything in my life, so I had a lot to learn. I wrote this post for those like me; if you have towing experience this post may bore you. 😉

There are two items Model X owners need to have before they can tow a trailer like an Alto which has it’s own electric brakes (California law requires trailers over 1,500 lbs gross weight to have their own brakes).

Braking the car and the trailer, together

A brake controller must be installed in the car so that when the car’s brakes are applied a signal is sent to the trailer brakes and they are also applied, proportionally. I chose a Tekonsha Prodigy P3 brake controller and installed it following the helpful instructions posted by Tesla Motor Club member @adelman.  Here are some details of my installation. This photo shows the brake controller mounted in the car.

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An upscale hitch ball

You also need a hitch ball (not supplied by Tesla with the towing package option) which connects to the car’s hitch receiver; the trailer tongue attaches to the ball. I opted to purchase the Weigh Safe hitch ball because it has a built in scale that shows the tongue weight.

The scale is not as easy to read as it could be; if the gauge needle was just a few millimeters longer it would touch the scale markers. This photo shows an indicated weight of almost 300 lbs when hitched up to my Alto trailer that was loaded up for a trip. I estimated the trailer weighed about 2,300 lbs.

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Note about measuring tongue weight: the car and trailer need to be level for accurate measurements.

Tongue weight is critical!

The Weigh Safe is certainly more costly than a standard hitch ball, but having the correct tongue weight is a critical safety parameter when towing; it should be between 10% to 15% of the total (loaded) trailer weight. If the tongue weight is too low the trailer can sway uncontrollably; too high a weight and the tow vehicle’s handling can be compromised.

Typically people use a portable scale to measure their tongue weight. But the weight can change depending how the trailer is loaded and how full the various water tanks are (the Alto freshwater tank is behind the axel while the grey and black water tanks are ahead of the axel). Carrying a separate scale is inconvenient and you may be tempted to skip checking the tongue weight before a trip. Having a scale built into the hitch ball means you can measure your tongue weight at any time; very convenient!

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The Bosal hitch that is part of the Model X towing package option specifies that the base of the hitch ball cannot be more than 0.75” above the top inner surface of the hitch receiver. When using the Weigh Safe hitch ball that means mounting it as shown above, in what most people would consider the “upside down” position. In that position the ball is within the required hitch specifications, but the part sticking down can scrape when going in or out of sloped driveways, for example. I purchased the 4” version of the Weigh Safe before I took delivery of the trailer. I was unsure of whether it would be best positioned “up” or “down”. It turned out that “down” was required. For the Alto trailer, that is the version I would recommend.

Weight distribution bars: needed or not?

The Tesla Model X is a heavy vehicle for its size;  over 5,400 lbs for the 100D version and of course hundreds of lbs more with two people and cargo inside. There is an advantage to that heavy vehicle weight: I do not need to use weight distribution bars with my hitch because the Alto trailer even when fully loaded weighs far less than half of the total tow vehicle weight. Weight distribution bars make hitching/unhitching more time consuming. Here is an informative discussion of weight distribution hitches on the Tesla Motors club forum. A Model X owner towing an Airstream Sport 22 using weight distribution bars — at a base weight of 3,634 lbs, much heavier than an Alto — ended up replacing their Tesla-installed Bosal hitch with a Draw-Tite hitch which is specifically designed to accommodate weight distribution bars. See this discussion.

Note: in the Model X owners manual Tesla states that the Bosal factory hitch is a “weight-carrying hitch” (which by implication means it is not a weight distribution hitch) and “You must use the Model X trailer hitch when towing a trailer. Never attempt to attach a different type of trailer hitch.” See this discussion.

When towing with the Model X  I can certainly tell that it is connected to something heavy at the rear, but with over 400 ft lbs of torque available from the two electric motors it’s easy to accelerate quickly when towing, and the precise low speed control provided by the electric drivetrain also makes it relatively simple to position the hitch ball under the trailer tongue when hitching up.

Life in the slow lane

Hitched up to the trailer, I drive conservatively and stay within the posted speed limits, especially on freeways which in California is a maximum of 55mph when towing. To my surprise I found it quite relaxing to be in the far right lane with the cruise control set at 55. Anyone who wants to go faster can always go around me, and so far no one has honked at me or acted annoyed that I was going slower than just about every other vehicle on the freeway.

Tesla’s Traffic Aware Cruise Control (TACC) function, which is part of the Auto Pilot option, is a wonderful driving aid on long trips since it dynamically maintains spacing to the vehicle in front of you. When towing it automatically increases the distance between you and the vehicle in front of you for an added measure of safety. Note that Tesla’s Auto Steer and Auto Lane Change functions, that are also part of the Auto Pilot option, are disabled when towing.

What about range?

Towing a large trailer requires a lot more energy due to the aerodynamic drag of the trailer. Gasoline cars use a lot more gas when towing, and electric cars use more electricity.

Tesla vehicles display energy usage in terms of “watt hours per mile” (Wh/mi); how many watts of stored electricity in the battery are used to move the car one mile (or kilometer, the display can also be set to the metric system). It’s the EV equivalent of MPG.

When towing a trailer like a Safari Condo Alto, at 55mph on a level road the Model X uses at least 30% more energy due to the increased drag. That means more frequent charging stops. Fortunately, the Tesla Supercharger network is extensive and expanding, making trip planning relatively easy. In addition, chargers that work with all EVs are plentiful, and RV campgrounds have 30A and/or 50A connections that we use to charge.

In our Model X 100D I find that I can go up to 150 miles before charging. A stop at a Tesla Supercharger takes 35 to 55 minutes and then I’m on my way again. When we stay at campgrounds with electricity  we charge the car overnight and then we’re ready to go in the morning.

However, the Tesla car navigation system does not accurately take into account the extra energy usage during towing and it will overestimate your projected range. It also assumes that you will be traveling at the posted speed limit, but when towing you typically travel much more slowly.

For detailed trip planning, use the EV Trip Optimizer app

For detailed trip planning and peace of mind, I highly recommend the EV Trip Optimizer for Tesla app! It allows you to accurately calculate how many kilowatts of energy you will use between any two points you specify and takes into account the trailer weight, your speed, weather, elevation changes, and more. It is really quite amazing.

It took us awhile to get used to towing a trailer and the hitching/unhitching procedures. My wife and I created checklists that we keep on our iPhones to ensure we do not skip any steps in the process. Tow safe, and have fun!

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2 thoughts on “Towing with a Tesla

  1. Pingback: Improving the already impressive Alto trailer | Electric Travels

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