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Truckers are even required to take a federally mandated 30 minute break[0] during the day, during which the truck can be recharging.

Industrial applications already consume much more power than an entire Megacharger site, so supplying the charger with power is an already solved problem. Getting power from the charger the truck is again, a solved problem in the industrial space. I can order an off the shelf industrial connector [1] that does 1000v @ 400A, which means you might need two of them. Truckers already use 2 pumps to fill their truck, so even that is not out of place.

[0] https://www.fmcsa.dot.gov/regulations/hours-service/summary-... [1] https://www.connector-techals.com.au/manufacturer/rauscher-s...

The regulatory info only gives information on the way things should be with regard to how truckers and the interstate highway system works, but I would suggest that before you invest on this hypothesis, talk to some truckers earning $0.50 per mile. And look at where semis actually park when they're taking their 30 minute and 11 hour breaks, before deciding how fast this transition will occur and how much infrastructure will have to be in place along the major cross country interstates like I-70, I-80, I-35, etc., before a trucking company or an independent trucker decides to go all in on electric.

(I don't know the answer, but I strongly suspect that regulations are not going to be the driver of the adoption of this tech. Short haul or "hot shot" could be better suited for electric and autonomous. Show me some progress there first and I will buy into some actual disruption. If you want a research assignment, take to the interstate back and forth across a couple of flyover states and stop and see where the trucks actually are.)

I’d argue that these trucks would be a much better fit in Europe than the US. Here truckers can drive a maximum of 9.5 hours a day with a 45 minute break. These are mandated by law and the pentalties are severe for going over these limits.

The range also lends itself nicely to this. Over the course of a day a trucker would drive a maximum of 855km (they are limited to 90/h), so with a short fast charge during their break the 500 mile version could easily achieve this, then over night it could be charged slower.

In the UK we also have very narrow delivery windows e.g. Be at Tesco in this 30 minute slot or pay a steep penalty. Scheduling a charging slot will not add much difficulty.

Logistics researchers have also been working on this problem for years. You can find paper after paper in the literature.

On other hand it looks to be about a meter longer than most trucks in Europe so that would mean it has to use shorter trailers, and I do not think the weight has been released yet, but I think it is going to be more than trucks now. And the maximum permitted weight in EU is 40 (except if you transport containers then it is 42).

>And look at where semis actually park when they're taking their 30 minute and 11 hour breaks

and you believe either the Trucking companies, the Regulators, or Telsa give a shit what works for Actual Human Truckers....

Telsa is looking ahead to full automation anyway so humans are seen as a inconvenience, and if they make it hard on Truckers that will just give them addition ammo for any concerns regulator have in replacing Truckers with Automation. To these companies The fact that is might be hard for Truckers to find a Charging station that falls in line with Hour of Service rules just proved we need to eliminate the humans

Good point, I guess, although I was responding to the parent's post that cited meatworld-based regulations as a compensatory excuse for the need for frequent recharging.

Sure, many electric and autonomous vehicle problems go away if we "simply" re-engineer millions of miles of roads and infrastructure in the country. Now you've got two problems.

Comparing on a percentage point basis, you have to ensure that the underlying physical system is equivalent, in this case, the capacity of the batteries.

Current superchargers charge at 2% / minute. I am assuming that's the maximum rate of charge, given the current supercharger infrastructure.

Lets assume that 2% / min is, say, at a 100 kW power level.

When charging a truck, assuming the supercharger technology isn't changed, the charging will still be at 100 kW power level.

So if the truck has 10 times the battery capacity, then the equivalent %age rate of charge will be 0.2%, not the same 2% as the capacity of the battery to be charged has changed.

Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger, or have some sort of port in the truck to which a special connector is connected to transfer huge amounts of power safely, not unlike a dock at the under side of the truck, or maybe the front.

I'm no battery expert, but is it possible that they have several battery compartments that can all be charged simultaneously? Thus reducing charge time?

Edit:

Just read the latter part of your post after I wrote this. I think this is the most likely scenario. "Personally I think Elon is either going to add multiple charging inputs per truck and combine it with a special supercharger,"

Yes it's possible. We could have a power port like a VGA cable with say 10 or 20 independent supplies, simultaneously charging the different battery units.

However those connectors will be very bulky and heavy. Maybe Elon is thinking of a mechanized system, say a power robotic arm sort of thing, or maybe tech similar to the instant battery changing station he demoed a few years back.

They do call it a "megacharger," and the port appears to have multiple connections

https://www.teslarati.com/tesla-semi-megacharger-charging-po...

Look at charging rates in watts (watt hours per hour) instead of in percentage; those semis have much larger capacity batteries, so they need a higher charging rate in W to charge 80% in 30 minutes than a vehicle with a smaller battery.

They don't have larger capacity batteries. They have batteries with more cells. Sure, the total charging rate is a higher Wattage, but you can charge cells in parallel.

The scaling here is exactly the same as with the "larger battery" versions of the Model S having more horsepower; higher capacity = higher throughput when you're dealing with battery banks.

Wait, are you concluding that having batteries with more cells is not the same as increasing the capacity of the system?

For any battery system, the capacity is the product of the number of cells and capacity per cell.

My point is that having a larger capacity battery automatically increases the wattage at which you can recharge. It's not like a gas tank where a 100L tank takes longer to refill than a 50L tank.

No, capacity of the battery isn't what determines the wattage at which you can recharge. It's the physical power supply constraints.

If I have a 250v, 25 kWh battery, I can charge it at 250 V, 100 Amps for 1 hour or at 250V, 1000 Amps for 6 minutes.

What charging rate I select depends on the voltage and chemistry in the battery. Can the battery support charging at such a rate. The charging current rate is limited to the max operating current of the battery.

If the above battery can supply a max current of say 50 amps, then you will have a max charge rate of 250V, 50 Amps for 2 hours.

What makes it confusing is that the charging rates are given as 10C, meaning 10% of nameplate capacity.

Might be fererring to nameplate power capacity.

nC means n*capacity/time, so 10C for 10kWh is 100kW

That’s wrong. 10C means 10x the nameplate capacity. If I have a battery that outputs 40Ah, 10C means I can give it a charging current of 400A.

Here’s some napkin math based on a few assumptions.

Assumptions: The article is correct and it’s an 800KW battery pack for the semi. I’m also going to go with a conservative assumption and assume 2C charging rate for the battery pack. I’m also going to assume that the semi will have the ability to take in a 480V charging current because it simplifies wiring and is easier to get in an industrial capacity.

With those assumptions, you’ll need 1.6MW of power, something that can be easily delivered with less than eight 500MCM cables (roughly 1” copper cables including insulation that weigh about 2lb a foot and are still rather flexible). This seems in line with the charging port photos I’ve seen for the semi. Neither the cables or the power needs are that dramatic, there’s wind turbines that put out that much power individually along I-70 in Kansas for example where there is thousands of them.

This makes sense--it explains why it takes as long to charge my mobile phone as a model S. Obviously different chemistries can charge at different rates, and the power supply and cooling needs to scale with the battery capacity, but if these are scaled then two batteries which use the same cells will recharge in the same time regardless of how many cells are in the battery.

I suspect Tesla's grid storage already proves this point.

I would imagine that the difficulty in charging is proportional to the cell's capacity, so charging 2*n cell shouldn't be any harder than charging n cells, as long as the cell's capacity is the same. If you increase the capacity of a cell, then you might have to innovate.

All these EVs use roughly the same small cells, right? Essentially thousands of the same cells used in hobbyist RC aircraft (with which I’m fairly familiar)?

Unless I’m mistaken, each little cell should theoretically be chargeable in parallel, limited only by heat, massively parallel wiring, and the one massive input carrying ridiculous current.

In theory, if one cell takes 30 minutes to charge, all cells could be charged in parallel in 30 minutes. Obviously this is ignoring the challenges I mentioned, which generally don’t apply to the relatively small RC aircraft with which I have experience.

If all of them are connected in parallel, then you are right. It's like filling an array of glasses in the rain.

However the superchargers connect to the vehicle through a power port, which is relatively small. So it may not have as many parallel connections. You could split the charging to individual cells inside the car, allowing for parallel charging of all the cells simultaneously, but that means that the supercharger has to handle the cumulative power requirement of all the cells in parallel. So if you have 500 50W cells, then the super charger has to have the capacity to handle 25 kW of power. And that much power requires some very bulky cabling, even with a 3-phase supply.

The parallel connections are visible: https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-...

Yup, definitely 3 phase. But then it has to supply a charger or an array of chargers on the vehicle that convert the power to DC, leading to increased bulk and costs. So we're back to the 501 terminal plug again.

Perhaps they’re looking into some even superer superchargers for the tractors. It’s a shame they apparently publicly abandoned the hot-swap battery system, although I can’t imagine they’re not still working on it, especially for the tractors.

You'd still have to transfer the heat from the cells inside the battery. That would probably lead to a design with increased battery surface, maybe even a radiator or cooling lines.

Already what happens. GM and Tesla use pumped liquid glycol for heating/cooling and some other companies use refrigerants.

Interesting. I did not know that. I always figured they must need to manage heat, at the bare minimum by preventing huge draw for extended periods of time. Do you know where they radiate the heat, given that most Teslas don’t (to my eyes) have visible grill vents?

You only need to do that when charging the battery.

Oh, do the batteries not heat up when discharging quickly as well? I know next to nothing about battery chemistry, but for some reason I just intuitively assumed they did. RC aircraft batteries can certainly catch fire if something causes them to discharge extremely quickly.

They discharge slowly during driving, unless you floor the acceleration while driving up a slope, but I'm sure there are some kind of limits in place, to prevent the user from draining an unsafe amount of power from the battery.

All Teslas have a grill in the front, it's down low. The battery cooling system is shared with the cabin cooling system.

They don't even need the 33% improvement. They could just add that much battery and fake the charge rate by misinforming the user about the charge rate. I.e. say it took 30 minutes to get from 0% to 80%, but really you went from 30% to 80%, the car just shuts down at 30%.

They already have firmware unlocked battery capacity in their currently shipping cars, so this isn't some wild conjuncture. The margins on these vehicles are huge, they can just decide they'd like to pay for marketing by cutting into some of those and shipping more batteries with each vehicle.

>"The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%."

I am curious what exactly happens at 80%, does that 2% a minute rate drop off precipitously? If so what is the reason for that?

Lithium Ion batteries are generally charged using a two step process of constant current then constant voltage. https://www.digikey.com/en/articles/techzone/2012/nov/consta... If 80% is the set point to switch over from constant-current to constant-voltage, then yes, the charge rate will drop continuously until it reaches full charge.

Half of the stories about Musk projects are just rambling about how what he's doing won't work.

I find that doing something that matters in life is not just hard because the task is difficult. It's hard because of all the people that gets in your way.

It's already painful to see people doing nothing by themself. Or even not helping the cause of others. But it's infuriating to see how much energy they spend to go against your attempts.

I'm just constantly surprised and exhausted at the kind of pessimism and cynicism on display in any Tesla thread. Even people who have no stake in the company or its competitors feel compelled to chime in just to say "it won't work!"

I don't get it. For better or for worse, Tesla has made the idea of electric cars feasible to the mainstream.

Surely, that can't be a bad thing. Why knock down the idea so aggressively?

I'm starting my own business myself, and I notice there are fundamentally 2 kinds of people.

One are the risk takers. Who know risks are involved, but do it anyway, sometimes against all odds, because the payoff (in any form) is big or huge. The risk is worth it for them.

Then you have the conservatives, who just don't want to fail. They take no risk, don't step out of their comfort zone, because they might fall down, they might fail. They want to be like all other people, average and safe.

I'm not saying either of them is good or bad. They just have a different take on life. I think conservatives are happier.

Problem is that when a conservative sees a risk taker in action, they don't understand it. They see all the possible ways on how this thing can fail. They ask why these risk takers don't see how this can fail.

Point is that the risk takers do know how things can fail, but do it anyway (ok, sometimes you do have stupid people who don't know). If it fails, they can proudly say "See I knew it! How stupid was that". Conservatives like to remain in their safe zone, where they know how things go. The risk takers always want to change things.

If anyone has another take on this, I would be glad to hear it.

I tend to agree, although I think this is probably a spectrum, rather than binary. Or maybe a bimodal distribution? I think that people probably tend one way or another, but we all probably display both reactions in different areas of life, at different times, etc.

I also think the terms you used probably aren’t ideal, because they imply a political connection that might make people resistant to your premise. It reminds me of the maker vs taker thing.

I like to think of it as reasonable vs unreasonable, as in the George Bernard Shaw quote:

“The reasonable man adapts himself to the world: the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.”

I totally agree. The naysayers aren't convinced that my designs for an interstellar pogo stick are viable. They just don't get my vision. Sure, there are some specifics to iron out and maybe it won't work but at least I'm trying to change things.

Best of luck to you.

It's typical anti-Tesla propaganda.

Agreed. I don't know why there's so much anti-Tesla sentiment on HN.

Smart people like to try to take down the smartest person in the room.