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upyoars t1_izyrim7 wrote

Can someone translate what "lower GVW than 81,000" means? Is that a good thing or a bad thing?

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domino2064 t1_izysz49 wrote

It means gross vehicle weight and the issue is that the Tesla Semi, demonstrated only had about a quarter to half of the load of a traditional semi, which is important, because in 2017, Musk said that these trucks would be more efficient than trains. 🙄

Also, the charge times aren't super great, and while he was pushing these semis, other automakers were expanding in the short distance, delivery sector with trucks that are arguably more practical and useful.

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fattymccheese t1_izyz5tb wrote

the article claims 72k lbs assuming a standard allowance of 35k for the vehicle and trailer itself... that's not 'about a quarter to half of the load'.. that's 3/4 of a standard load...

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Miserable_Ride666 t1_izyttxp wrote

Someone else may do a better job but the total weight of the truck, trailer and load cannot legally exceed 81,000 pounds. Gets more specific by axle.

Most regular tucks you see on the road can haul 40,000ish pounds of freight.

Would love to know what the max cargo weight a Tesla truck can haul.

Also a not completely packed trailer does not mean it's not pulling a full load and it would be spaced out with more in the back to even out the axle weight.

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Sans_culottez t1_izyv6iu wrote

IIRC they upped the GVW to 83,000lbs about for electric semis, but that doesn’t matter much for long haul trucking, since the current battery package for the Tesla Semi is close to 11,000lbs.

Edit: Ah, it is in fact 82,000lbs: https://ops.fhwa.dot.gov/freight/pol_plng_finance/policy/fastact/tswprovisions2019/index.htm

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privated1ck t1_izz0y0j wrote

This guy's YT video says the Semi has special permission to go to 82k pounds.

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Sans_culottez t1_izz48r6 wrote

It’s a good video, but it has some problems.This only looks at the energy efficiency costs on a per mile basis, a lot of trucking profit is made by moving mass tonnage in a specific timeframe. Even with special dispensation to run at a higher total tonnage, if you’re still losing out on total cargo tonnage it won’t make sense yet.

It can make sense, for mid-range hops from a supplier shipping exactly one product (like coke or pepsi), and would eventually make more sense as charger infrastructure got further down the line. Especially since theoretically you also require less maintenance on EV’s in general.

But semis get in lots of accidents too, and I’ve yet to see one of these go up in flames in a tunnel.

I also question how well the efficiency and torque math works out if they have to go through a mountain range.

Edit: that actually lead me to a horrible thought, like it’s sometime before every car is an electric vehicle, but I know of tunnel accidents that have killed close to a hundred, what happens when every car involved is also a highly explosive hot burning fire that can’t be put out with water?

I could see the internal temps of the tunnel near the accident setting off other batteries and the internal temps of the tunnel in general to be too high to safely deploy rescuing teams. Hopefully this will be less of an issue if we can move to safer battery chemistries.

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Angry_Tau t1_izz7dkt wrote

Regarding your edit, yes this is absolutely a fundamental flaw. This is one of the many reasons why from a civil engineering perspective, the Loop/Hyperloop (and similar battery-powered gadget-bahns) are laughably bad ideas.

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Sans_culottez t1_izz7z1k wrote

You can’t even put out those fires without flooding the tunnel with chemicals that will kill humans.

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gerkletoss t1_izzdsda wrote

Why would hyperloop have a fire problem?

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Angry_Tau t1_izzjhyp wrote

As far as I'm aware, the basic idea is that the compressor and running gear would all be battery-powered, given that the concept relies on "gliding" through the tube without any contact--ruling out an external power source like a third rail or catenary.

Furthermore, lithium battery fires oxidize themselves--even if the tube were completely devoid of air (which isn't actually the plan anymore), battery fires would still occur.

And finally, the proposed "overhead tube" or underground tube infrastructure makes fire escape much more complicated and difficult. Conceivably, at the very least if you had limited mobility, escaping a sealed steel tube either up or down would pose a significant challenge. Given the nature of historical tunnel fires, even most able-bodied people probably wouldn't stand a chance.

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privated1ck t1_izz6z3r wrote

This video has lots of problems, lots of assumptions, just look at the comments. But I'm pointing to the 82k weight limit assertion only.

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Sans_culottez t1_izz7t3o wrote

I think it was worth watching even with its lofty assumptions and math favoring Tesla, because that’s like: best case scenario if they deliver on all of their claims, and only assumes transportation and vehicle costs. And that’s not something that makes them look particularly good even then.

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privated1ck t1_izzb4h7 wrote

This particular youtuber is not a Tesla fan by any means, he wrote a highly skeptical article about electric versus gas energy efficiency.

But he made a whole bunch of assumptions here that he could have easily gotten more specific on, and left out some significant factors like brake regeneration.

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Sans_culottez t1_izzbeun wrote

Yeah brake regen can help particularly over inclines on the down slope, but as a contrary: what about when the EV had to be stuck on an upslope in bumper to bumper LA traffic? What about transit lines through the north during winter? Like I’m actually interested in seeing real world efficiency tests.

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privated1ck t1_izzc61g wrote

Well that's the beauty of regen. Any energy expended during acceleration can be largely recaptured during deceleration, especially if you have 80,000 lb driving the wheels that are driving the generator. the majority of energy that's lost is due to wind resistance and rolling resistance. It's a known fact that electric vehicles are more efficient in stop and go traffic than they are on sustained Highway driving. Which is exactly the opposite of an ICE vehicle. When a truck is going up a grade it is running at a lo enough speed so the drag ceases to be a significant issue. None of this was accounted for in that video that I quoted.

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Sans_culottez t1_izzcsi0 wrote

That’s cool, I just kinda wonder about the truck that’s been stuck for 4 hours on an upward slope, like it’s not that that it doesn’t happen to ICE trucks either, if they got low on fuel and got stuck, but if that happens, they can get AAA or highway patrol to come out and give them a bit of fuel to get further down the line to the next station. What happens if an EV truck gets stuck in a situation like that where it tried to get over a hump that shouldn’t have taken much power, while not being at peak power itself, and then sat there for so long because of an accident that it could no longer get further up the hill?

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privated1ck t1_izzg7a8 wrote

I suppose they will bring out a generator 🤣

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Sans_culottez t1_izzgert wrote

That’s a capable enough fix in theory, but involves a lot more supply costs.

Edit: assuming both trucks have fully functional working engines and have just ran low on fuel:

You pay the person delivering the fuel to the ICE truck, the cost of their time and fuel costs, they deliver it, the truck gets on their way.

It takes maybe 15 mins to refuel the truck.

For a generator: you pay a lot more for the weight of the generator, plus fuel, plus the time it takes for the person who delivered the generator to run it and charge the EV.

It takes 15mins to set up the truck and the generator, and then at least another 30 to charge the truck assuming the best charging and generator tech available.

That’s not an insignificant amount when you consider you are also blocking off a road way to do this for a lot more time.

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privated1ck t1_izziorg wrote

Only thing that matters to big logistics companies that buy semi tractors, is over the aggregate, does it save money?

Also. I am not an electric truckologist, but I'm not sure that sitting for 4 hours doing nothing but heating/air conditioning the cabin or even running a refrigeration unit on the (presumably well insulated) payload would put a significant drain on a 500 mile battery. And this is a bit of an extreme situation, involving someone who went into the mountains unprepared for the possibility of sitting on a road for 4 hours.

Again with regard to my first comment above, we're not concerned about "black swans", if in the aggregate significant money is being saved on shipping.

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Sans_culottez t1_izzj0r6 wrote

That’s because at the moment they are allowed to offload a lot of the externalities of their business not only onto their drivers, but on the public as a whole, i see that getting clipped down somewhat (hopefully) as those externalities start being subjected onto the average person in a more readily identifiable way.

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Sans_culottez t1_j005jfx wrote

Regarding “black swans” when considering a logistics fleet that does not have a fairly secured transit line like trains (again the answer is always trains.), these sort of “black swan” events happen every day on on a major truck transit hub.

And something like a battery tunnel fire is equivalent to a black swan event like the Hindenburg.

You can’t just write them off as statistical noise.

Edit: like this isn’t me just shitting on EV’s it’s obviously the way of the future if you want to survive climate change.

But it’s going to involve infrastructure costs that are not reflected in the price per kwhat hour of travel. Like in general even with ICE trucks I think there should be laws and physical barriers that slow ALL traffic during tunnel entry, and probably roadway laws that make you follow other trucks 3 car lengths away when entering a tunnel.

It’s just when a tunnel accident happens that is full of fires that can’t be put out without killing people, and even then it does millions of damages to tunnel structures, that I think these kinds of logistical costs will actually be considered.

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privated1ck t1_j008wbr wrote

I'm pretty sure that a semi tractor with full tanks of diesel fuel is just about as dangerous. You can't put that fire out with water either, and in fact diesel fuel flows and floats, making it possibly even more dangerous than a lithium battery fire.

And in a world where major manufacturers choose to pay accident victim's families instead of recalling dangerous vehicles, you can be damn sure it's all about the money.

But that's outside my scope here.

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Sans_culottez t1_j00a2nj wrote

Well that’s kinda my point, existing regulations about transportation of fuel trucks discourage them from going through tunnels, generally.

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privated1ck t1_j00cisc wrote

Not talking about a fuel truck, I'm talking about a semi tractor with side tanks full of diesel fuel for the tractor.

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Sans_culottez t1_j00d6gr wrote

Okay, we’ve already accounted for that for ICE trucking, but we don’t put that shit in our actual total volume of inventory by Mile, even now.

Like I’m not okay with how ICE trucking companies let off their externalities onto their workers and other people that have to be on the road. But they already do it.

And now you’re introducing another very different engine plan that is evaluated without any of of the logistical hurdles, only the specific engine costs.

That’s not gonna work.

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privated1ck t1_j00eb62 wrote

When you speak of companies who "let off their externalities" onto others, I assume You're about the trucking companies that employee independent truckers who own or lease their own vehicles? Assuming I understand what you even talking about, that's not the model that works best for an emerging technology like this. I'm talking about massive logistics companies with their own fleets. They can afford to absorb the initial costs, and average out the effects of cost and risk over a large number of vehicles over a large amount of time with plenty of capital to cushion the shocks.

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Sans_culottez t1_j00f40v wrote

Oh no, I I mean all logistics companies that happen to involve truckers. They by and large treat all of their workers like shit, it just gets a lot worse with “independent” trucking companies like you mentioned.

Even the best companies, that treat their workers the best (which basically doesn’t exist in the US), still offload a lot of externalities onto the localities that they work through, they just don’t offload it onto their workers directly.

You end up paying it through taxes to repair your roadways, only that’s the only way you see it when you’re a flyby town with only a gas station, and then wonder why no one in your town ever gets up unless they get out.

Edit: also, I’m not a demon mind that figures all this shit out for the company. I’m just someone with a weird intelligence that just so happened to have a lot of family in the trucking industry.

The demon minds will figure this shit out for the logistics companies, after your town has been burnt to the ground from them figuring it out.

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privated1ck t1_j00wdcg wrote

This comment thread is getting way off track. The way the trucking industry treats its workers is completely independent of whether those trucks are electric or petroleum powered. The question of whether fleets will replace their petroleum-powered trucks with electric powered trucks is strictly a matter of the economics of one versus the other, all other fixed costs/common considerations being equal. And large companies will be the movers in this space because their economies of scale make the risk proposition worthwhile.

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Sans_culottez t1_j00wqfe wrote

No honestly it is very much not. The way the trucking industry gets away with pretending it is efficient In the US is by offloading externalities onto its workers and municipalities.

It’s passing the buck right along, and that’s very easy to do so long as someone else gotta pay for it.

Edit: and yo, again about how somebody else has to pay for it, how many truckers you know ended up with a crank habit to make their deadline?

That’s company time you gotta pay on your family line.

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Ancient_Persimmon t1_j03ksye wrote

If it's in bumper to bumper traffic, it will barely be using any energy, so it would give an increase in efficiency.

Cold weather negatively affects range, but that effect will be less significant than with an EV car, since some of the factors such as interior heating and winter tires play a much smaller part in energy usage on a Semi. The cabin may be a little larger than a car, but not substantially so the amount of heat needed will be similar. Semis don't switch tires in the winter.

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gerkletoss t1_izzdmj8 wrote

>But semis get in lots of accidents too, and I’ve yet to see one of these go up in flames in a tunnel.

EVs have fewer fires per collision than ICEs.

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Sans_culottez t1_izzdr5l wrote

Yes, but the fires are of a completely different quality and require completely different methods of putting out.

Vodka burns different than styrofoam and gasoline.

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Ok-Welder-4816 t1_izzynro wrote

Eventually we will get solid state batteries working. Those do not combust no matter what you do to them (short of, like, throwing them in a smelter). They also have many other advantages: much greater density, unlimited lifetime (because of no electrolyte eating away at the poles), ability to use them as structural components, faster charging...

There are such batteries in the works, but the problem they have a lot of catch-up to do. Even if they're 50% better, than current lithium, lithium keeps getting better every year, so it's a moving target... when solid state hits the market in 5 years, it's advantage may be gone, until it also benefits from years of improvement.

Hopefully, eventually lithium tech will hit a plateau, and then it will make sense to switch to pouring all our resources into solid state.

There are also partially solid (gel-like) electrolytes already in use, that are significantly less flammable than liquid.

On the other end of the spectrum, there's research into sodium batteries. These store a lot more energy than lithium, but also make a lot bigger boom. Like the difference between a car fire that's difficult to extinguish and, well, a 2000lb bomb... But for applications where performance is the only thing that matters, they sound pretty cool.

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swanspank t1_izytcw4 wrote

GVW is Gross Vehicle Weight. That is the absolute total weight of the passengers, tractor, container, and freight typically given for the maximum capacity the vehicle is rated to carry. The question appears to be was that the specified weight capacity it is capable of transporting OR was that the weight of the vehicle and the cargo it was actually carrying during the specific test.

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