Range reduction when towing.

[batufrommongolia]

how much range reduces when I tow with cybertruck, let's say im towing 5000lb.

for a traditional truck, I know when I tow something heavy, my mpg reduces a lot. I think this should be same on cybertruck right?

Do you want to use cybertruck to tow?
how much you tow usually?

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[Dids]

how much range reduces when I tow with cybertruck, let's say im towing 5000lb.

for a traditional truck, I know when I tow something heavy, my mpg reduces a lot. I think this should be same on cybertruck right?

Do you want to use cybertruck to tow?
how much you tow usually?

It is unknown because we don't know the relevant specs how much range reduction will be. But a good guess is less range reduction than a gas truck due to electric high torque component of power. The real difference will be in refill time.

 

[craz]

I believe Model X owners see approximately 50% reduction in range at most. Obviously this is highly dependent on altitude, speed, towing weight, trailer size, etc so your results may vary. The aerodynamics of the trailer will likely have a bigger impact on range than the towed weight.

 

[Dids]

I believe Model X owners see approximately 50% reduction in range at most. Obviously this is highly dependent on altitude, speed, towing weight, trailer size, etc so your results may vary. The aerodynamics of the trailer will likely have a bigger impact on range than the towed weight.

I don't think the cybertruck will be affected as much as the Model x. The model x uses induction motors. An electric motor is most efficient when it is under a full load, so for model x efficiency reasons Tesla would not have put a much bigger motor than is needed for non-towing use. This means that when model x is towing it's motor is not at full back emf and is slightly leaking. ( Not all the energy goes to power, it is wasted as heat).
The cybertruck will not have this problem because it will use switched reluctance motors. With switching you can alter the timing to increase torque at the expense of top speed. Cybertruck will have a tow mode. I believe this mode means top speed will be dropped from 130 to say 85. power= torque x rpm so if you lower the rpm you get more torque. I have seen electric motors where you can set the timing for as much as a 20% difference in torque.

 

[craz]

I don't think the cybertruck will be affected as much as the Model x. The model x uses induction motors. An electric motor is most efficient when it is under a full load, so for model x efficiency reasons Tesla would not have put a much bigger motor than is needed for non-towing use. This means that when model x is towing it's motor is not at full back emf and is slightly leaking. ( Not all the energy goes to power, it is wasted as heat).
The cybertruck will not have this problem because it will use switched reluctance motors. With switching you can alter the timing to increase torque at the expense of top speed. Cybertruck will have a tow mode. I believe this mode means top speed will be dropped from 130 to say 85. power= torque x rpm so if you lower the rpm you get more torque. I have seen electric motors where you can set the timing for as much as a 20% difference in torque.

Good points. The Cybertruck will probably have several innovations focused squarely on increasing towing range, but the basic physics aren’t changing. I’d still expect at least 25% range reduction in most cases.

 

[Bamaboy007]

It will be dramatic

 

[TyPope]

Hey guys, have you heard anything about whether or not I'd be able to tow a 5th wheel trailer with the Cybertruck? I know the range will suck with a big trailer but I have one that I don't use for anything right now but storing moving boxes and the snow thrower/motorcycles depending on season. I have an F350 that I'm about to sell but don't really want to sell the trailer but if I sell the truck, I can't move the trailer. We only use the trailer for storage and moving which we shouldn't be doing for a few more years.

So, I'd really like to find out soon if there will be a capability to have a goose neck hitch installed or if the bed would support a 3rd party solution.

 

[ldjessee]

If the 5th wheel or trailer is designed right, it should not be as big of a hit as a 'one size fits most' trailer.

 

[Newton]

It will be very high, greater than 40% why? Because aerodynamics. The cybertruck and evs in general rely heavily on its drag reduction. The trailer will negate alot if the vehicles aerodynamics at the connection point(that beautiful slope on the back of the truck won't be much different than a regular truck when towing) PLUS it adds even more drag from the trailer itself. PLUS the weight and slight friction from the trailer.

Now, if they can make a parachute type material (but flexible)connection between the trailer front and trucks backend, or even top, thus closing that gap. It would reduce the drags losses from the truck trailer connection, basically making it 0. So the trailers backend drag would be the issue. And that is usually very high as it's most likely a large rectangle with a non-tapered rearend. But that too can be altered with an attachable tail panel like the "trailer tail" or vortex generators although unproven I have seen they do help.

Longer post than I expected but some info

 

[ldjessee]

I have seen studies and testing that shows that some trailers, designed right, decrease drag, as they help put the air back behind the truck.

Some custom made trailers that the back end looks more like the nose of a boat turned upside down really smooths out the air, causing dramatically less drag.

Bridges (bridging the gap between the two) made of highly elastic material, say spandex, has been tried by many DIYers and unless it is pulled pretty tight and tested, usually it balloons up pretty bad. Here is one with it pulled tight to stop ballooning. https://smg.photobucket.com/user/tomausherman/media/CIMG2935.jpg.html

Most people think for a shape to be aerodynamic it has to have a point at the front, but a very aerodynamic shape, the rain drop, is pointy at the rear.

 

[Dids]

Hey guys, have you heard anything about whether or not I'd be able to tow a 5th wheel trailer with the Cybertruck? I know the range will suck with a big trailer but I have one that I don't use for anything right now but storing moving boxes and the snow thrower/motorcycles depending on season. I have an F350 that I'm about to sell but don't really want to sell the trailer but if I sell the truck, I can't move the trailer. We only use the trailer for storage and moving which we shouldn't be doing for a few more years.

So, I'd really like to find out soon if there will be a capability to have a goose neck hitch installed or if the bed would support a 3rd party solution.

People say the sail sides will interfere, but I don't know if they thought of using CT lowered with a higher 5th wheel.
What is your clearance on the goose neck?
The bed can support/ haul 3500lbs. Why wouldn't it be strong enough to handle a 5th wheel?

 

[batufrommongolia]

basic physics is energy = mass * force * distance.
so towing more means mass becomes larger, energy cost will become larger. but battery is same, so distance has to be smaller.

 

[ajdelange]

Energy = force*distance where the force here is drag. Energy is also consumed when accelerating and in going up hill. This is proportional to mass but much of it is recovered by the regenerative braking system. Thus while the inertial and gravitational (mass related) loads may be the biggest in an ICE vehicle drag tends to be dominant when a BEV is used. This is not directly related to mass except in the sense that a more massive trailer is likely to have larger frontal cross section.

 

[ldjessee]

Unless going up hill or down, the difference mass makes is inertial, starting and stopping, as well as a small load increase from increased friction on load baring parts that move.

The math is done well here:

But he makes the assumption the trip requires traveling 100 miles up hill, gaining a mile in altitude. Where I live, that is impossible without flying.
If the trip is from a west coast city, it is possible and on the east coast it is possible, but less likely (mountains are not as tall).
He also makes the assumption the trip will require towing the max weight capacity for that vehicle.
For the CyberTruck numbers, he has it pulling a 14,000lb trailer. He does not keep the load the same across vehicles (the Model X is pulling a 5,000lb trailer). Which to me is not a fair comparison.

If you look at the energy breakdown, you will see that the energy required for the 75mph trip that aerodynamic is the highest of the three listed. Even for the CyberTruck, though the numbers are closer, the energy for aerodynamics is still the highest.

Yes, weight will cause there to be more energy expended than without it, but the speed driven at makes a bigger impact on the energy needed than weight does, especially if you are towing less than the max capacity of the CyberTruck.
The formula is Energy (Work) = Force (which includes mass) * Distance.

 

[ajdelange]

Yes, weight will cause there to be more energy expended than without it, but the speed driven at makes a bigger impact on the energy needed than weight does, especially if you are towing less than the max capacity of the CyberTruck.

In general the inertial load is the largest load on a motor vehicle but as I explained in my last post with a large amount of inertial (and potential) losses recoverable in a BEV drag assumes greater relative importance, especially at higher speed. Towing around town (lawn service for example) inertial/potential will be the big determinants but out on the highway drag will become more significant if not the most significant. Which load is bigger under which circumstances depends on so many things that it is really not possible to make statements any more specific than these broad generalities. It should be pretty clear than drag isn't going to be the big load going up a 15% grade at 40 mph.

The formula is Energy (Work) = Force (which includes mass) * Distance

Yes, that's the formula but no, force does not include mass except where acceleration is involved. The drag on a sphere in free fall is the same whether the sphere is solid osmium or a paper thin hollow aluminum ball. The drag depends only on the speed, the drag coefficient, the frontal area and the density of the fluid. Thus the mass of the fluid is a factor but not the mass of the trailer. IOW while the unit of drag force is kg-m/sec^2 (just as it is for any force) the kg are those of the air - not those of the trailer. Another example would be the work done by one of the motors. It is equal to the force times the radius times the angle turned. The force depends only on the stator magnetic field and the current induced in the rotor. But the force require to accelerate a given mass is F =m*a i.e. determined by the mass and the acceleration. When accelerating the energy is still E = m*∫a*v(t)dt =m*∫a*a*tdt = (0.5)*m*v^2

We often speak of kg force (which I don't think we should because it leads to confusion over this). The kg force assumes that we are in the earth's gravitation field (9.8 m/s^2). On Mars a kg would exert much less force on a horizontal surface).