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That Tesla Semi

The reporting seems to be that the Tesla Semi truck has just done what near all said couldn’t be. Carrying a full load for 500 miles without recharging.


Not wholly, entirely, convinced myself. Now, I don’t know ’bout US rules but here in the UK it’s the total, laden, weight of the truck that is allowed onto the roads. If the batteries weigh several tonnes more than a truck with an ICE and a diesel tank then that simply must mean a reduction in carrying load – beause trucks do tend to bump up against that allowable upper limit of total weight allowed on the roads.

So, I’d guess – guess – that the total allowable carrying weight of that Tesla Semi is lower than of a diesel truck. Meaning that it’s not the price of the truck plus fuel, it’s the price of more than one truck (say, 1.2 trucks, just to have a number) against one truck.

However, it’s also possible to think back the other way. Actual truck loading is a weight/volume problem. Carrying a truck of potato chips isn’t 40 tonnes. Carrying a truck of Pepsi cans is – we might well not fill all the volume before hitting that weight limit.

So, say that the Semi can only carry – because battery weight and total loaded weight limit – 80% of the normal maximum weight load. That’s only a problem for things which do hit, on that weight/volume basis, the weight limit of the load, isn’t it? And how much of road freight does that?

I’ve no idea what the answers are here. I think I’d get close to insisting that given battery weights then total possible carrying weight is lower. But how important that is I don’t know – because how many truck loads are weight, instead of volume, limited?

We got any experts around here?

43 thoughts on “That Tesla Semi”

  1. US highways are long, straight and flat with little congestion. So mostly constant speed, not stuck in streams of slow moving traffic. very little stop/start, or hills to climb.

    Try it London to Edinburgh see how it works out.

    And yes: fully ‘laden’ raises the question… laden with what?

  2. I’ve heard one point about “hills”. Both techs use the same energy to climb them. Only electric captures some of the energy back into the batteries of coming down one.

  3. And how much load is not just about weight but volume too. Those batteries have to go somewhere. Where? It seems unlikely they will be in the tractor unit due to lack of space and axle weight restrictions, so it is likely they will be in the bed of the trailer to spread the load over all the axles. This will intrude into the cargo space, reducing volume.

    And another consideration. If the ‘semi’ is a flatbed to take a container box, the increased tare weight due to batteries means the weight of the container load must be reduced – that has implications for shipping costs since weight limits for container boxes will have to be reduced for electric trucks, meaning more boxes to carry the same load.

    And… logistics. Since for a period in this magical change over from ICE to electric, trucks picking up container boxes at ports will be some EV, some ICE – marrying up container boxes with reduced weight limits and matching them to EV pick up is going to be, er, challenging, unless ALL shipping containers have reduced weights – then we have a big, big cost.

    Also… just because something is possible doesn’t mean it is practical or desirable. It is possible to circumnavigate the globe in a ship with sails, but we don’t do that any more… soon maybe.

  4. @TW.

    True, but recovered energy will never equal that expended. Also not all hills have a down side – they often climb to higher ground. Other hills may have a gentler, gradual down slope which still requires power to maintain speed, so any recovery will be insignificant.

    There’s also journey time to consider. The longer the journey – congestion or gradients to negotiate, the longer aircon/heater and other electrics are needed which all have to come from the batteries.

  5. You say “semi” I say “artic”. Which means I don’t have to guess whether Yanks say sehmi or seem-eye.

  6. California is proposing to ban all diesel vehicles, or at least the sale of new ones, in the next several years. If that happens, and Gov Newsom loves to do this sort of stuff, and if it’s the case that EV large trucks carry less cargo, then it’ll be yet another factor increasing costs on citizens while doing very little to affect the climate issues.

    Did I read somewhere that the Dutch are abolishing agriculture? Is this a plan to shorten average heights?

  7. Just a reminder, there are no climate issues. This is very slowly starting to dawn on more and more people now. You would think that after four decades of failed predictions the climate doom people wouldn’t have a shred of credibility left but here we are.

  8. The write-up I’ve seen quotes 2kWh per mile, which is twice as good as a Tesla car – a mate with a Tesla says he gets 4.2 kWh/mile. Near on 1000kWh of batteries must take up a lot of space – perhaps they stack them behind the driver. You can’t really put them in the trailer as it’s then no longer an interchangeable unit like all other semi trailers are.

    My money is still on diesel for trucking. I have diesel vehicles & don’t intend to get rid of them.

  9. No one seems to have mentioned that recharging time after 500 miles. Will the pickup points be cluttered up with recharging trucks instead of just filling them up with diesel, loading them up and getting rid of them?

  10. Tractor. Don’t you have that backwards, ie. 4mi/kWh? Even the Ford EV pickup gets about 2mi/kWh, but less if towing.

  11. Climate nonsense and hysteria will be ignored soon – the favorite, “ten years left”, idiotic statements only really work on young people who haven’t heard them before.
    But, despite these false justifications for moving away from diesel, a hybrid truck might have some advantages – a small battery, used for limited range travel in cities to reduce pollution, with a diesel engine running at its peak efficiency to recharge the battery once away from the centre. This would all be housed in the tractor unit.

  12. If it’s any good to you, I was reading about something like this recently. Weight limit for diesel trucks in the US is 80,000lb (IIRC) Electric gets a slightly higher 82k. To get the same run range as a diesel semi, you’re probably talking in terms of 8 tons more weight.

  13. For “range “you probably need to be talking about the maximum hours a driver is allowed to drive, expressed in distance, for the diesel. Because a refuelling stop doesn’t really eat into that. But for electric, with recharge times much longer, it’s really the distance on one charge.

  14. ” likely they will be in the bed of the trailer to spread the load over all the axles”

    That won’t be possible either – trailers have to be fungible. Any truck can take any trailer because you don’t spend time waiting for *your* trailer to be loaded, you come in and grab one ready to go.

    But as for space in the truck, the engine compartment is now empty – the motors are in the wheels. That’s where you put your batteries.

  15. But, despite these false justifications for moving away from diesel, a hybrid truck might have some advantages
    It isn’t quite that simple. The legislation that been imposed on emissions for diesels in the States have meant on energy consumption cost & reliability*, electric’s approaching comparability now. Although the smart money’s on hydrogen for the future.
    *Modern low-emission diesels with urea injection are just not as reliable as the old diesels that had million mile life expectancies. It was generally the truck structure that failed before the engine/drivechain did. A lot of them now do the final miles of a trip being towed.

  16. Aligning charging stations with mandatory rest periods is also going to be a problem.

    Maximum of 11 hours of consecutive driving (and no more than 14 total ‘on duty’) after a 10 hour rest period, and a 30 minute break after 8 hours of driving (these are the federal, thus minimum, limits, states may be more strict).

    Right now a trucker could stop at a rest stop or even off the side of the highway to rest – won’t be able to do that if you’re coming up on the end of your charge.

    And 11 hours of driving at, say, a 50 mph average will mean you’ll need to stop to charge at the end of every long-haul shift.

    Right now these trucks would work for short trip cargo between a couple nearby cities but its not going to be used for long-haul trucking like this.

  17. Incidentally lads, that last bit of info’s got me thinking. The current V-dub I’ve been driving’s been enough trouble as it is. But it isn’t the “blue” diesel model with the urea injection system. Thank heavens I bought an earlier rather than later model. Be warned! S’not the only car to have these systems fitted.

  18. Also run into problems with split-driving – where you take a second driver who can sleep in the truck’s berth so you don’t have to stop (except to fuel). Again, unless there’s a charger every 400 miles you can’t charge at all and even if there is, you’ll spend so much time there that its not worth doing the split-driving.

  19. “Although the smart money’s on hydrogen for the future.”

    Hydrogen, outside of solid-oxide fuel cells (which can do the fuel cell thing straight to fossil fuels) or fuel reformation (where the engine breaks fossil fuels down into hydrogen and CO2/water and burns the hydrogen) is a non-starter.

    BMW just made a hydrogen-fueled car. If it sits in your garage for two weeks the gas tank will drain itself. And you can’t actually put it into a garage because it bleeds off hydrogen gas as the tank interior warms up. And the tank takes up the whole back seat.

    Running an infrastructure on super-high pressure H2 (for pumping metal hydride storage) or cryogenic H2 (for direct usage) is more of a pipe dream than powering all the cars in the country on ‘renewables’.

  20. The trucking industry already has a partial solution to the charging problem. Several companies (UPS for one), plan their routes so their drivers drive half their allotted time out, drop the trailer off, pick up a trailer going the other way and are back home for the night. This is usually for the workers benefit and convenience and not because they are concerned about charging the truck batteries. Though it should work well in this instance. Note, the solution doesn’t have to be for all trucks and trailers just the use case that that makes sense.

  21. 1 kg of hydrogen has the fuel equivalent of a half-gallon of diesel weighing 2.4 kg.
    Great! And the siesel tank is a light sheet-steel box structure or two.

    But 1kg of hydrogen comes in a 5′ long steel gas cylinder weighing 100kg.

    So instead of a truck tank of 100 gallons of diesel (say) at 500 kg, you can have the hydrogen equivalent for only 20 tonnes of gas cylinders. And those 200 cylinders, each 5′ long by a foot in diameter, will nicely fill up the cargo space anyway, so the axle weight remaining won’t have any room for cargo! Neat.

    What a no-brainer.*

    Some countries and states will quietly forget the ‘no diesel-powered vehicles’ rule.
    The others will starve.
    One will be happy and silent, the other will also be silent. At last.

    *And therefore assured to be a campaign pledge of Biden-Fetterman 2024!

  22. @AJ: it had just occurred to me that you could use diesel tractors for pulling trailers through the wide open spaces and then an EV tractor could do the last miles in built-up areas. Could that be remotely practical?

    If practical what would make it economic?

  23. @dearieme
    Read what I wrote above. The emissions regulations on diesel trucks are becoming so restrictive that they’re making them non-viable. Where they’re being driven doesn’t make a difference. The economy’s dropped & so’s the reliability. If the sensors detect the emissions going outside the parameters the EMS stops the engine. Can you see them relaxing the standards for non-city use? There’s always going to be some residential adjacent to any highway at some point so anywhere can be regarded as a “built up area”.

  24. Bear in mind that many long-haul trucks in the US operate with team drivers, so they can run virtually non-stop for extended periods. Large parts of the supply chain, especially fresh produce, absolutely-depend on this mode of operation. Unless there is a 10-minute battery-swap system, a 500-mile range is not going to work for that portion of the industry.

    It should also be borne in mind that US trucking varies widely from region to region – the East coast is relatively flat, and so the trucking is relatively easy, but anything in or over the Rockies or the Appalachians, for example, involves endless heavy up-grades – usually followed by down-grades, to be sure, but that only helps so much. And you can’t change the fact that trucking from Chicago to Denver, for example, is effectively up-hill all the way.
    We’ve just seen with the Ford 150 electric that real-world towing and hauling performance can fall far short of real-world requirements. Combine that with previous promises (see Nikola, for example ) and you’ll forgive me if I take a wait-and-see attitude.



  25. PS forgot to add that, while the US Interstate GVWR is 80,000 pounds, the average weight of a long-haul semi-truck and trailer combination is actually about 56,000 pounds, due to the volume/density queations described above (figures several years old, maybe OOD). Of this, the tractor is 15-20,000 pounds, depending on configuration. So there may be room under the Interstate weight limits for a significantly-heavier tractor unit without impacting payloads.

    The average semi-tractor engine and transmission weighs between 2,000 and 3,000 pounds.



  26. Agamammon

    Yeah but it doesn’t really matter unless your garage is a completely sealed pressurised tank. All the hydrogen will simply disappear into the drive.

  27. One further thought, after looking at Tesla’s marketing – it shows the tractor as having tandem drivers. Now, if the tractor has several extra tons of batteries aboard, and a 53-foot tandem-axle trailer at or near the Interstate maximum of 56,000 pounds, I’d be interested to know how they’re satisfying the Federal bridge-loading formula,N%22%20of%204%20axles).

    while still keeping the whole rigging less than 65 feet long. I suspect that the different weight distribution may mean that specific load and balance will be required to keep the axle loads of tractor and trailer within allowable limits. It’s mot enough to say ‘at the allowable GVWR of 82,000 pounds’ unless they also say ‘without special loading restrictions’.



  28. @BiS: we bought a new diesel a few years ago. I say “new” but we were careful to buy a 2005 model. Even the 2006 regs (or round about 2006 anyway) were too pernicious for us. It’s still only done 200,000 miles so it may have plenty of life left. I hope so: we’ve just put on new tyres all round.

  29. It’s a bit more complicated than total weight. The main concern is the axle weight. A good rule of thumb is 11,000 Kg per axle. Then there is a maximum length, which cannot reasonably be increased as the vehicle length dictates the corners it can use. And the height, which again cannot be increased because it would limit the routes that can be used due to low bridges. Tesla have said that the payload they can carry is the same (or more!) as for diesel HGVs.

    If there was a way of increasing the payload, it would have already been used to increase the payload of diesel lorries.

    On the subject of range, this is easier for artics than cars because the purpose of a car journey is often to transport the driver, while the purpose of an artic is to transport the load. If the range is insufficient for an artic, you can swap the tractor and keep the load moving. However, in the UK that should not be necessary. Regulations require a driver to have 45 minute of rest after 4.5 hours of driving, which is a ratio of 1:6. As long as your charger can charge six times faster than the battery is drained while driving, you’re ok (once electric HGVs are popular enough that rest stops will have chargers).

  30. I’ll be having some Real Life™ comparisons in about a year or so, given that our Masters of Management have Pikachu’d our region’s Salvation Army maintenance department, where I volunteer, for EV trials.

    Which means that 2 of our 4 Caddy’s will become electric versions… Joy.
    Given that our current turbodiesel-driven bricks are never overloaded and are not fitted with reinforced suspension by us ( looks innocent..) and we’re allowed to do nothing to the new cars… well.. Interesting Times.

    I expect the one destined for the Rotterdam runs ( which are pretty standard-ish..) to live pretty well through things, but the one meant for “Everything Else”…
    That one gets to go to locations in the ass-end of nowhere where you have to bring everything + the house to prevent having to drive all the way back to…. That one’ll be getting a real workout..
    Especially since Rotterdam has plenty charging points, but our other locations…. Not So Much.. Nothing conveniently at the sites anyway.

    Not semi’s, or long haul, but I’m curious to see how well the things ( which are simply the electric version of the cars we already use ) compare in use and useability.
    ( and have made some realistic/pessimistic entries in the betting pool, of course..)
    Nothing like Trial by Fire to see how things really work, after all.

  31. @Charles 3rd para
    Sure, the small size of the UK would make domestic electric road haulage more feasible. But the infrastructures going to look a lot different to what it does now. If you’re proposing trucks pull off for a recharge every 4.5 hours, your service areas are going to look a bit different. Currently the truck pulls onto a pump & pulls off typically in around 10 minutes. The rest period can be taken anywhere. Service area recharging for multiple rigs, you’d be talking around 10 times the footprint of the rig to get on & off the charger, plus the feeder roads. That’d be an awful lot of expensive land.

  32. Does no one here think that by the time these trucks are ready for sale that they will be driverless? That would change the economics of running trucks somewhat.

    I read today that Scania are doing driverless truck tests in Sweden right now.

  33. Ottokring – not before it rises to the ceiling and collects around dodgy writing or dust covered electronics;)

    As much as BMW are pushing this concept car, they’re the one telling it’s not safe to garage.

  34. The way of increasing the payload is that legislation has been amended to allow EV-HGVS an extra 2000 lbs laden weight – i.e. 82 tons rather than 80 all up. No laws of physics broken.

    Mechanically, there’s no reason this shouldn’t work (give or take reasonable differences that operators may be willing to swallow).

    The interesting question becomes one of practicalities:
    1) These things call for 1 megawatt chargers – so for the moment, you’re not going to see them on any national network
    2) That huge battery and high tech truck is going to be quite expensive as an upfront cost
    3) Trucks are then run for long term profit, so endurance, reliability and service costs are very important

    The secondary question becomes one of legislation – where and when will operators be forced to buy these things, and how will road tax be calculated?

    For once, Musk might not be selling snake oil here, but the haulage industry is rather different to the fickle car industry, so it’s anyone’s guess how much of the market he can capture. Be certain that Volvo and other companies are going to be hard on his shirt tails for this one.

    For some operators with fixed routes and clearly defined internal needs, an EV-HGV may be a very attractive proposition.

  35. @ Dearieme
    Mmmmm… The Eos is a 2012. I’m seriously thinking about dumping it & going for a mid ‘0’s Sebring for the same reasons as you. I need another 4 seat hard top convertible so it’s back to beautiful Yanks! No BM’s or Mercs for me. I don’t want to undergo the sort of character change they induce in their drivers. Audi? Nah. Just a V-dub for posers. Shame about the need for the two extra seats. I get damp around the gusset just thinking about a Crossfire.

  36. Buses based in large stations on fixed routes might be interested in EV.
    For the rest, there is an enormous change of land use involved. Your local gas station becomes totally uneconomic, the out of town supermarket with the huge car park becomes clogged with EV chargers and aimless shoppers or has to be even bigger with entertainment.

  37. To those talking about hydrogen: take a look at the restrictions on propane-powered vehicles. Then realize that hydrogen is much more dangerous: it is explosive over a larger percentage range mixed with air and the resulting energy is much larger (why they wanted to use in the Shuttle after all).
    Then realize that we still have gasoline fires after a hundred or so years of experience with using it in vehicles.
    Hydrogen is a non-starter, for about the same reason as nuclear-powered cars.

  38. Actually, nuclear-powered might be better on first look – the tiny amount of fuel needed would mean you could add a fair amount of weight in shielding. I’m not sure how efficient something that small would be though.

  39. M,
    Decay-based atomic power sources are too low-power, and to make them powerful enough you need some really active isotopes = insanely low half-times.

    And for fission power sources.. You can’t make them safe in engine size at the power needed. By the time we can build that small safely, it’s much more efficient to build a Neighbourhood Nuke to generate the electricity needed for the EV’s.
    Scale matters..

    Fusion? You run into the fossil fuel v/s hydrogen problem. Hydrogen doesn’t carry that much potential energy, so by it’s nature it only works in bulk reactions to generate enough power.

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