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| © Tesla Electric cars like the Tesla Model X can pull, but they can't do it for long. |
They can pull, but they can't do it for long.
A long-range Tesla Model X
can tow up to 5000 pounds, and the automaker claims over 7500 pounds of
towing capacity for its upcoming Cybertruck. Respectable numbers, but
here's the thing—today's electric cars, regardless of make, just aren't
great for towing.
As Engineering Explained's Jason Fenske describes in this
video, the energy density of electric cars leaves much to be desired.
The current state of battery technology is such that only so much energy
can be stored in a package that's not too big for a passenger car. The
Model X's 100-kWh battery pack has the most energy storage of any
production EV. The EPA certified the Model X Long Range as being able to
go 328 miles between charges.
When you add a trailer to the mix,
that range goes way down. Fenske details a couple of hypothetical
trailering scenarios for a Model X in this video. In one, he simulates a
family taking their Model X on a camping trip, driving 100 miles up a
1-percent grade at 75 mph. Factoring the 5500-pound weight of the Model X
itself, plus 500 lb of payload and 5000 lb of trailer, increased drag
coefficient from the trailer, rolling resistance, and gravity, Fenske
calculates that 100.4 kWh is needed to make that trip. In other words,
you'd need to recharge to make it.
That's not factoring use of
HVAC and other ancillary systems either. Fenske calculates that doing
the same trip without the trailer would only take around half the
energy, and towing the trailer at 60 mph requires 84 kWh of energy.
Essentially, a trailer can kill EV driving range.
For comparison,
he runs the same 75-mph trailering uphill scenario with a Ford F-150.
That truck comes with a choice of 23- or 36-gallon fuel tanks. Given
that a gallon of gas is equivalent to 33 kWh of energy, that means the
Ford has around 775 to 1200 kWh of energy capacity. The trip would
require 170 kWh of energy, so the 23-gallon F-150 would only need to
operate at around 21 percent efficiency to do it, while the 36-gallon
truck only needs to work at around 14 percent.
Fenske also runs
some numbers on the Tesla Cybertruck based on preliminary specs, and
calculates how the Model X trip would go with no incline and going
downhill. The numbers are a lot better, but still a ways off the F-150
going uphill.
So while you can tow with an EV, they won't be
practical tow vehicles until their energy capacity increases
significantly. When the Model X offers a 200- or 300-kWh battery pack,
towing long distances will be much more practical.
