Tesla Semi’s Enormous Battery Might Weigh 11,000 Pounds on Its Own | Hacker News Reader

Tesla Semi’s Enormous Battery Might Weigh 11,000 Pounds on Its Own

thedrive.com

51 pointsourmandave74 comments

11,000pounds for a battery implies 170Wh/kg. High end lithium ion cells can do about 300Wh/kg, and even with some overhead for the battery, we’re talking 250Wh/kg.. So… That’s beatable, & we can’t back out the weight directly from the energy of the pack as we know Tesla has been working on improving chemistry and specific energy and pack efficiency.

Anyway, the claim by Musk that they can achieve 1.5kWh/mile is reasonable, and fits in with my calculations here: https://selenianboondocks.com/2017/11/tesla-semi-part-1/

The vehicles that they delivered did not use all the available aerodynamics tricks that their prototypes did, and uses duals instead of super singles, so it also makes sense it’s only achieving 1.7kWh/mile right now.

Note that a ton of people claimed a 500 mile electric semi with a full load wasn’t feasible. This proves that it is. (The jersey barriers they pulled weighed about a standard 44,000pounds.) The Toyota hydrogen semi has only about a 300 mile range and with fuel an order of magnitude more expensive.

You're talking about battery cells, but you need to look at the battery _pack_ energy density. The model 3 battery pack, which uses the same cells as semi, is about 170Wh/kg. The numbers in TFA are very reasonable estimates.

I already addressed that by including mass overhead for the overall battery. And sure, it’s always possible to assume more conservative numbers for a whole battery and assume Tesla DIDN’T do any engineering work to reduce overall battery mass, but that’s not something you should put in a headline.

(Tesla has typically done better than their peers in overall battery specific energy as well as energy per mile.)

You're using a 16-17% figure for packaging overhead? That's low. Even with relatively expensive construction techniques (for example if you're doing EVTOL) you see 20-25% packaging overhead.

I agree, but a long haul, full payload electric Semi is a very challenging project comparable to an electric aircraft since you’re limited to near the same maximum total weight. I’m merely pointing out that such a battery pack is one possible solution, one that cannot be ruled out based on public information.

The in-use 2170 batteries are apparently 250Wh/kg. With that figure and a more realistic packaging overhead of 30% I'm seeing something like 190Wh/kg, which is more in line with your observation.

From the numbers I can find, the Model S 85kWh has 7104 18650 cells - if we use 49g for mass of cell, that's 767lb of cell vs the pack weight of 1200lb~, or a very rough packaging overhead of ~36%

This is a naïve analysis but it helps assuage my ego, as I've worked on designs for 26650 based packs where we would have been quite happy to hit 30% overhead :) That being said, I realize people can, and do in fact make more mass efficient packs.

Wow, selenianboondocks. That's a blast from the past.

Okay, cool.

So if I read [1] right, some kind of average price for electricity used in the transport sector in the US as of September 2022 was 12.48 cents/kWh. That would mean that the 500-mile trip costs 500 * 1.5 * 12.48 / 100 = $93.6 in energy.

If that includes hauling tens of thousands of pounds of cargo, that sounds rather a lot like it would make transport powered by electricity commercially sane, right? Nice.

EDIT: I hadn't read the article much; it seems the current power value given is actually 1.7 kWh/mile, so that increased the price to 500 * 1.7 * 12.48 / 100 = $106.08. Not a huge increase, obviously.

Thanks for that math. Seems relatively cheap. How does it compare to gasoline?

(500mi / 6.5mpg) * $5.313 = $408.69

6.5mpg - I just Googled average MPG for a fully loaded Semi, could be wrong.

$5.313 - Most recent highway diesel price (https://www.eia.gov/petroleum/gasdiesel/). I'd expect this is high due to fleet discounts and such.

I feel like that average is really low. Talking with my buddy who is a trucker, he said that 6mpg is on the low end. His truck, which isn't anything special, would usually get 8-9. He said those guys getting 6 or lower are usually owner / operators who have older trucks, either because they like the older trucks or they can't afford to get a new one. Most fleets have much newer trucks, a lot of which can get up to 10mpg or more. That may not seem like a huge improvement, but over thousands of miles it adds up really fast.

Semi-trucks use diesel. Diesel is between $5-$6/gallon:

https://www.eia.gov/petroleum/gasdiesel/

Let's use $5/gallon.

According to random website https://motorask.com/semi-trucks-mileage/

> On average, semi-trucks get around 6.5 miles a gallon

But according to https://www.motorbiscuit.com/how-many-miles-per-gallon-do-se...

> Transporting freight from one location to another isn’t cheap. We all pay so much for shipping because semi-trucks are gas guzzlers. In the early ’70s, it was estimated that the average semi got about 5.6 MPG, but that amount has increased slightly. In 2014, new semi-trucks were required to get 7.2 MPG on average.

Heck, let's use 10 MPG.

500 miles ÷ 10 miles/gallon x $5/gallon = $250.

So even with liberal estimates in diesel's favor, unless my numbers are way off, electric comes out way ahead.

....per trip. What about lifetime?

With a more pessimistic 6.5MPG, using mbell's math, that's 82 cents per mile in fuel. Electric is 19 cents per mile.

An average semi lasts 750,000 miles: https://www.tristatetruck.com/blog/posts/what-is-the-average...

Let's assume for a moment that Tesla has made a motor and batteries that will last that long (far from guaranteed). Heck, let's take some random internet claims at face value and say that the motor will last "millions" of miles and the batteries will last 300,000 miles: https://www.vehiclehistory.com/articles/how-many-miles-will-.... Will these batteries last 300k with a likely use case of being driven to their absolute maximum range every single day?

In that 300,000 miles, the fuel savings of electric will save you 300k * (0.82-0.19) = $189k. Replacing all the battery modules in a Model 3 (82kWh) will cost somewhere in the range of $25k. How much would replacing this giant battery cost?

It's possibly better, but the math isn't particularly clear.

A dead battery isn't dead, it just has a reduced capacity. Usually the battery is considered dead at 80%, so it's a 400 mile truck then. That 400 mile truck is still useful, so it'd probably be cheaper to sell the 400 mile truck and buy a new truck then to replace the battery and sell the old battery.

Another question is: how much of the savings in fuel costs going to go to the operator and how much is going to go to Tesla in purchase price? 5 years ago it was announced at $180K, but it's certainly going to sell for a lot more than that. A Nikola Tre with 360 mile range goes for $270K, so it's quite possible that Tesla will charge $400K for theirs. So you might start off at about $250K in the hole so it'll be hundreds of thousands of miles before the Tesla is cheaper than a diesel.

If the battery lasts 2000 cycles (reasonable for good chemistry… some chemistries can last over 5000 cycles), then that’s 1 million miles. (Tesla’s powertrain is certified for that much, too). At electric 19cents per miles and diesel at 82 cents per mile, that’s $630,000 in savings just for fuel, not to mention Diesel Exhaust Fluid, oil changes, and brakes.

The 500 mile range Tesla Semi cost $180,000 at launch. Let’s say they’re off by nearly a factor of 2, so new Semis will be $315,000. That means you’ll be able to buy 2 500 mile Tesla Semis for just the fuel savings from one.

You're selecting a gas price at all-time highs:

https://agtransport.usda.gov/Fuel/Historical-Diesel-Fuel-Pri...

A fair assessment would be $3/gal (what it was prior to 2021). That changes the price dynamics rather quickly..

Further, you get less bang-for-your buck on electric vehicles in the cold. Everything from the breaks to the power runs less efficiently and you'll lose range / capacity.

I don't see this as a super good deal, though for potentially for short-haul (i.e. a few hundred mile) trucking situation(s).

Just because it's cold outside doesn't mean the truck is cold. Sure it'll be less efficient starting off in the morning, but once it gets going it'll warm up quickly. The truck might be 92% efficient at turning electricity into motion, but 8% of 1.7kWh/mile gives you 130W of heat.

130 watts is nothing in this context?

One issue with most lithium chemistry is that it isn’t rechargeable below freezing - it causes permanent damage to the pack.

Practically speaking, this is solvable using in-pack heaters which divert the charging power to warming up the pack first. This takes time if it’s been allowed to sit. Laws of physics and all.

Charging these batteries is also going to take time, a lot of it, and significant charging infrastructure.

Short haul might go through a tank a day, but long haul often uses two drivers working in shifts and can cover 1000+ miles a day easily. It takes 30 minutes or less to refill a diesel long haul truck.

Unless they can get charging times down to an hour or less (which if it is a 875kwh pack like some folks think, that means literally megawatt sustained charging rates), it would require a major change in how long haul truckers work to have a chance.

Current superchargers max out at 250kw, which at max rates would take 3-4 hours to recharge, and they require a decent amount of expensive infrastructure to be able to support that.

If it is much cheaper, that could happen though!

In the video of the delivery event they announced new Megawatt chargers.

Not only did Tesla announce Megawatt chargers they claim will do 70% charging in 30 minutes, but this isn't a sleeper cab, so you're not going to have two drivers doing shifts anyway. And there's no need to worry about the pack freezing during use. The pack can be thermally insulated and the temperature is typically controlled via a coolant loop, possibly using a heat pump to maintain temperature. They're also typically automatically pre-heated before leaving.

If you plug in to charge immediately after driving, the temperature issue isn't a problem as both charging and discharging the battery produce some heat.

(Additionally, the "can't charge below freezing" is a chemistry-dependent thing... it's really only essential for certain chemistries like lithium-iron-phosphate, not the type they're using on the long range Tesla Semi... although acceptable charge rate does reduce at lower temperatures due to lower charge-carrier mobility IIRC.)

Stopping for 30 minutes to add another ~350 miles to the range will mean that a driver won't be limited by the truck in how long they can drive in a day. Additionally, charging is way safer than pumping diesel fuel, so drivers don't need to tend to their truck during charging (unlike fueling), freeing them up to rest or clean up or eat.

Tesla has done an excellent job installing Supercharging infrastructure in the last 10 years in the US (better than everyone else combined, although it's getting better), so installing Megacharging infrastructure seems like something they'll be easily capable of.

Thanks for correcting me! That does indeed seem like they have a very solid product now.

Even at $3/gallon it’s still $150, so that’s 50% more than the electric cost.

I also realize there may be other trade offs and costs involved. The energy cost was asked about so that’s what I answered.

FWIW: I own a 2017 Volt and love it. 50 miles all electric then another 350 or so ICE miles. Those 50 miles cover ~ 90% of its lifetime miles. Electric here is 0.11/kWh. I really wanted the flexibility of electric and gasoline having had reliability issues with both energy sources here in NC.

You appear to be shadow-banned because of your second ever comment, which, while wildly offensive, does not appear to be a statement that you believe but instead an explanation of what Meloni believes.

> If that includes hauling tens of thousands of pounds of cargo...

That is the question. I am very curious if that includes cargo and if so how much weight. I suspect it doesn't include cargo. If it doesn't include cargo, diesel trucks will be far cheaper

If you're looking at historic fuel prices ($3/gal diesel [1]) and what modern trucks are getting (7-10mpg [2]) with loads. You're talking ~$150-$215 for a diesel truck. Plus you have fuel everywhere (less infrastructure costs), quicker refuels, easier repairs, etc.

The cold and time will also siphon off the efficiency of the battery powered trucks. Colder climates will see a 5-10% drop in efficiency in winter, and that'll grow over time. Making it less cost effective in northern climates.

The only way this truck makes any sense would be short-haul (single day round-trip deliveries) and government subsidies IMO. Plenty of market, but not quite where it needs to be.

[1] https://agtransport.usda.gov/Fuel/Historical-Diesel-Fuel-Pri...

[2] https://lonestarclassictruckclub.org/average-fuel-mileage-fo...

Had you bothered to watch the presentation from last night, or done any cursory research this morning in place of inserting your "suspect it doesn't include cargo", you might know that this includes 82,000lbs of cargo.

Tesla also released a video[1] showing a time-lapse of a fully loaded truck going from Fremont to San Diego fully loaded with no charge stop. (The trip does include a 30 minute bio break as required by law.)

[1] https://youtu.be/GtgaYEh-qSk

We need to taxes vehicles by weight. Vehicle weight is the biggest contributor to road surface wear. The damage cause by trucks accounts for 99% of road surface damage. [0]https://www.insidescience.org/news/how-much-damage-do-heavy-...

Prettttty sure that's the case in the U. S. Are they taxed enough? There's a strong argument to say that they're not. But here's just one URL indicating that there is a tax on heavy vehicles: https://www.irs.gov/newsroom/truckers-must-pay-heavy-highway...

Seems like it would probably be a bigger win to put a 100kwh pack in and create a modular generator package. A lot of the polluting big rigs do is particulate matter when accelerating. Using batteries as the buffer between power generation and power consumption would do a lot of good.

Being able to run different kinds of small 20-80hp generators at their max efficiency RPM would be great. And if it were a reasonably sized module different folks could compete to make different highly efficient generator packages running on gas, diesel, CNG or LNG, ammonia, DME, hydrogen, ethanol, or whatever.

I think you are describing a hybrid. The power company at my previous location had hybrid rigs for working on high voltage [1]. There are also hybrid fire engines. [2]

[1] - https://www.pge.com/mybusiness/environment/pge/fleets/

[2] - https://chargedevs.com/newswire/los-angeles-fire-department-...

No? A hybrid powertrain is really expensive by itself, requires a more expensive-per-kWh battery pack, and has little efficiency advantage over an optimally geared Diesel engine in cruise, as it’s already running optimally.

And you’re only making a marginal improvement in CO2 emissions. All the synth fuels are much more expensive than electricity.

Right but even the 'diesel in cruise' is still less common than you'd think. There are hills up and down, there's passing, there are bridges, headwinds and tailwinds, etc. Required power is different if you're fully loaded vs partially vs empty vs no trailer. Even on interstates there are towns every 50-100mi that have their own traffic and thus non-cruise speeds.

If the exception to cruise is only 0.1% then I agree it's dumb to consider. If it's 10% or more and the emissions during non cruise are significantly worse, it could end up accounting for 30-40% of total emissions instead of just 10%

So, a hybrid truck? You can just buy those from Volvo or Scania right now. The problem is it does nothing to gratify the ego of America's foremost megalomaniac.

It also does almost nothing to reduce emissions since the emissions benefit of a hybrid over a well-geared diesel truck is negligible.

In long haul service, but in local service it can easily double the fuel efficiency and eliminate particulates that diesels generate in transient operation.

But then why tow around that huge, expensive engine if you’re not using it? Tesla makes a 300 mile Semi as well. A 100kWh hybrid battery would experience a lot harsher cycling conditions than a larger battery in a pure electric Semi would.

I guess it's a question you'd need to ask the 1000s of customers who have bought existing HEV and PHEV trucks, not me. There's clearly some niche for them. Anyway if we're going to talk about "dragging around" something then obviously the main thing we are going to discuss is 5 tons of dead batteries, not a teensy little diesel drivetrain that maybe weighs 1 ton or less.

The idea that extra battery capacity is “dead weight” is a common misconception that belies a common ignorance about the electrical and chemical properties of batteries.

For a given chemistry and power and voltage, doubling a battery’s capacity will halve the battery’s internal resistance, thus improving its charge and discharge efficiency (as well as increasing the maximum charge and discharge power). It also halves the “C-rate,” thus allows it to last more cycles… and because the size is doubled, the number of miles per cycle also doubles. You can also afford to operate the battery with much larger margins, in its optimal state of charge, going from 75% to 25% state of charge, instead of hammering it from 100% to 0% (which would quickly wear it out, not even counting the difference in C-rate).

Sure, this still needs to be balanced with weight and cost, but a larger battery than you strictly need is NOT, in any way, merely “dead weight” in the way the ICE engine and fuel tank is in a PHEV like the Volt when I drove it for 6 months at a time while never using the engine.

Thats a series hybrid idea. they are already doing that, however, car industry has been exceptionally poor in making a efficiency optimized generator mostly because their R&D depts have been tweaking engines that operate over a big rpm range to send power directly to wheels. the design gets much simpler if you are making a high efficiency generator. recently companies like Aquarius have done some work on that.

That said, the main utility for hybrids is in stop&go situations where gas engine has to operate over a large RPM range and energy is essentially lost in stopping. In case of big rigs I actually agree that you need full electrification (or maybe ammonia/H2 engine IFF conversion efficiency to carrier is high). We 'just' need to get the battery energy density up 30-40%. Quite doable IMO.

There are a few startups that are doing carbon capture for trucks the closest to a market solution is probably https://remoracarbon.com/ they also have an interesting business model where they offload the CO2 and sell it off and have a profit sharing with the truck/fleet operator.

It doesn’t solve all emissions problems like NOx and other particulates but it’s a good step and likely we will be seeing both electrified trucks for short hauls and carbon capture for long hauls and for more efficient reuse of existing vehicles.

Hot swap and multiple sizes (weights) of battery would be very killer features.

Fleet vehicles like this are exactly where it makes the most sense to have a stop and swap strategy for refueling, especially when so much energy needs to be transferred at once. Though that is lessened by the size of the battery since they could argue it gets recharged during a mandatory rest period.

The tesla semi already comes in two battery flavors. It's already quite good flexibility.

> Hot swap and multiple sizes (weights) of battery would be very killer features.

That also means the batteries must be carried like cargo. That'd add a lot of extra weight.

Is it really a problem ? I mean, apart from the quantity of lithium needed to create this « enormous » battery, is weight a real limitation factor ? We currently have no info on the full truck weight but I am sure Tesla found ways to optimise weight everywhere else. Mechanical components for a 1000000 miles rated vehicle are heavy and without a gearbox and a crankshaft, I assume the rest of the truck is lighter than its gas counterparts. I am no expert so maybe we are dealing with other orders of magnitude. Anyway, would this impact the maximum cargo weight ?

Speaking as a former shipping and receiving guy, well, yes. It suggests some 11,000 pounds less capacity on a standard semi, which are highly regulated as far as maximum weight/mass goes.

You can make some of that back by the removal of the engine and fuel (though you still need something akin to a motor and perhaps a transmission). Likely parts of the truck will have to be converted to aluminum - perhaps the trailer itself.

A full semi can have 300 gallons of diesel which itself is about 2000 pounds, so we're down to a 9,000 pound difference.

And some percentage are short haul, which are often not even near to fully loaded. Could be as high as 40-50%.

A semi weighs between 10,000 and 25,000 lb. A semi's ICE engine weighs around 3,000lb.

I don't work in the industry. I just observe three things:

1) the weight variance of a semi encompasses the amount imputed to the battery

2) 3,000lb of weight can be saved by not having a diesel engine plus another 2,000lb not having fuel. (Both of which will be in the total gross weight of the semi) some of which will of course be replaced by electric motors.

3) it's a speculative weight. It might also not weigh that much. Might is doing a lot of heavy lifting.

A fourth point: trucks routinely travel partly empty because of weight distribution issues. Not every TEU is full.

Logistics is fascinating. TCO is the closest most computer scientists get to "how can owning a Mac be cheaper than owning a Windows PC" but logistics does this almost every sum. Weight and carry capacity may not be the sole deciding factor here when a semi is worth $500k and has a 2nd hand value and is a finance decision with tail costs and operation costs.

Except the vehicle has made weight reductions elsewhere, including engine, transmission, emissions control, fuel tank, etc. A typical useful payload is around 44,000pounds still keeping under the 80,000pound limit, and the Tesla Semi was able to do that (electric trucks are allowed ~2000pounds extra).

2,000 extra pounds for electric vehicles.

Though I only gave it a quick search and it seems annoying difficult to find straightforward spec sheets for semi tractors like you can for any piece of CAT equipment, [0]"As we highlighted above, there are several ways to measure a semi-truck’s weight, and the maximum legal weight for a fully-loaded semi in the United States is 80,000 pounds. The lowest unladen weight is roughly 25,000 pounds, but will typically be closer to 35,000."

So, 10,000+ pounds for the power pack alone is a sizable chunk of the maximum allowable weight, and could potentially eat into the allowance for cargo, more so for restricted routes like older inner city bridges with tight weight limits and the like.

[0]https://www.jdpower.com/cars/shopping-guides/how-much-does-a...

I’m curious how often fully loaded semis hit 80000 lbs. a quick google seems to show me maximum capacity instead of average/median weights…

Agricultural products, heavy equipment hauls, bulk materials, etc. regularly hit 80k pounds and above. Truckers picking routes to bypass scales is a meme for a reason.

Not at all uncommon, though my experience is with equipment rather than general containerized or palletized cargo.

e.g. a CAT D8T bulldozer weighs in at over 80,000lbs all on its own and they are often trucked around as a complete unit, so you're looking at 20-35,000 more for the trailer and tractor to haul it. Heavier pieces of equipment like D9's (108,000#) or D10's (145,000#) are generally 2-3 loads of chassis/tracks/blade&attachments.

Just an aside, a D9 is a real hellbeast. I got to drive one on some forestry work and there's not much out there that makes it stop moving. Gives me a stiff willy just thinking about it.

Both the CAT D9 and the Tesla Model 3 Performance advertise 450 HP.

Drivers being ticketed for overloaded trucks was a constant complaint in my childhood home back in IL, where the head of the household owned a concrete construction company.

Apparently the highway patrol would camp out in the industrial/shipping areas and watch for compressed suspensions/bulging tire sidewalls on big trucks as a monthly fundraising exercise.

Obviously there's a business incentive to move as much as you possibly can at once...

>watch for compressed suspensions/bulging tire sidewalls on big trucks as a monthly fundraising exercise.

I am unhappy with this description. An overloaded truck is a safety issue, and also a long term road-wear issue.

> I am unhappy with this description. An overloaded truck is a safety issue, and also a long term road-wear issue.

Sure, except this fundraising didn't stop the activity. It just took a cut from the profits, and the vehicles drove off AIUI. This was Illinois in the late 80s-early 90s I'm talking about...

It's not about safety. The 80k limit comes from limiting wear and tear on roads. Pretty much every semi truck is built to tolerate 120-150k without caring though wear and tear on the trucks really starts to increase a lot beyond that.

Some states have higher weight limits when the ground is frozen.

Any time you see a trailer that carries some sort of bulk good it is safe to assume that that trailer is right at the max weight.

EV trucks are allowed to have a maximum weight of 82,000 pounds instead of 80,000 for ICE trucks.

Tesla does get a small buffer for the battery size, due to EV trucks being allowed 82k instead of 80k lbs max.[0] Doesn't save the entire extra budget though.

[0]: https://afdc.energy.gov/laws/11682

> NGVs and PEVs may exceed the federal maximum gross vehicle weight limit for comparable conventional fuel vehicles by up to 2,000 pounds (lbs.). The NGV or PEV must not exceed a maximum gross vehicle weight of 82,000 lbs. (Reference Public Law 116-6 and 23 U.S. Code 127(s))

The Youtube channel Engineering Explained went over the Tesla Semi, and the weight of the EV cab should be pretty similar to an ICE cab. Also EV trucks are allowed another 2k pounds.

https://youtu.be/Uv44W7xa4IU

"Also EV trucks are allowed another 2k pounds" - Ah that explains the 82,000lbs mentioned in the Tesla demo. Max weight for conventional trucks is 80K.

There were about 10-12 concrete barriers as load in the demo each weighing 39,000lbs. So the weight being carried is around 40ishK lbs. So rough approximation - half the weight of the truck is load and half is the truck itself.

> ... but I am sure Tesla found ways to optimise weight everywhere else.

This is kind of a "the entire industry is dumb" assumption.

I mean, sometimes industries are dumb, and there are certainly people driving oversized vehicles on the road right now, but if you can find places to optimize vehicle weight outside of the engine/transmission/fuel you're replacing with batteries/motors, that applies to regular old semi-trucks; if you can make a semi-truck weigh 5000 lbs less without compromising on its design parameters, you can make every other semi-truck on the road more fuel efficient and save like 6% of your fuel costs, while also allowing you to haul bigger loads than competitors' trucks.

Everyone making semi-trucks is interested in that, not just Tesla.

Everybody else is using a chassis designed for ICE, so something that handle a vibrating 5000 lb engine, a vibrating 1000lb transmission and can hang 2000lb in fuel. They then need to add reinforcement to hang a 10,000 lb battery.

I'm fairly confident some of the rest of the industry could get a comparable weight if they started from scratch and they optimized for EV only. But that's two assumptions that don't currently hold.

I wonder if this will lead to increased or decreased quality of life for truck drivers. The UK and EU are still aligned on truck driving rules for the time being. In the UK, trucks are limited to 60mph on the motorways which means there's a theoretical max limit of 540 miles a day on a standard day or 600 miles on an extended day. It's also mandated that you have to take at least 45 minutes rest every 4h 30 minutes which I imagine should be sufficient time to charge the vehicle to get the extra 40 - 100 mile range so I don't think EU drivers would really be impacted at all. It may have more of an effect in other countries which have higher speed limits however.

I believe the laws in America are much looser so the effects there may be far greater. I believe US truck drivers can drive for up to 12 hours, so if these were widespread you would imagine US truck drivers may be getting more and longer breaks than if they were driving ICE.

Summary of EU Driver Laws for anyone interested: https://www.gov.uk/drivers-hours/eu-rules

> be sufficient time to charge the vehicle to get the extra 40 - 100 mile range

I think 45 minutes is enough to get closer to 300 miles of additional charge than 100.

Could a different technology, one perhaps with a higher weight per Wh but a higher Wh capacity per volume, make more sense in a semi-trailer-truck? Since on some routes they cruise for up to 11 hours, the weight could be less significant that a car doing city driving.

I wonder if hydrogen fuel cells driving electric motors would work in this case.

Yes, but the range wouldn’t necessarily be better. IIRC, the Toyota hydrogen semi has a range of about 300 miles. And very little fueling infrastructure (with extremely expensive fuel). EDIT: yup: https://www.hotcars.com/heres-what-you-need-to-know-about-to...

Also, it’d require dumping a lot of heat. I talked to a contractor who once helped make the Nikola One heat exchanger, and he said it took as much power as a Nissan Leaf powertrain just to cool the dang thing.

oh that's super interesting. thanks!

So, the big issue everyone seems to be ignoring here is momentum and control, controlling a 20,000lb tractor is going to be hard and incredibly dangerous in bad conditions.

11000lbs -> 5t

When one of those inevitably goes up in flames, it is going to be hella impressive.

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