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Tesla’s promises don’t compute with current physics and economics of batteries

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Re: Tesla’s promises don’t compute with current physics and economics of batteries

#91

Post by nimos »

petre wrote: post #81
baddox wrote: post #48

Earlier quoted context omitted.

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 ch…

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.

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#92

Post by _ph_ »

lukealization wrote: post #25
_ea1k wrote: post #14

Earlier quoted context omitted.

I don't really agree. If another company rolled a 200kwh car out of the back of a truck, did a few passes of the stage, gave passengers rides (high speed launches) for a while, and then reported ~60% battery remaining, I think most would believe them. We would also wonder about making it to production, but Tesla actually has a halfway decent track record at that.

> If another company rolled a 200kwh car out of the back of a truck ... That's the thing. They didn't. The roadster concept didn't have 200kWh in it at all.

It might not have exactly 200kWh of battery installed, but one reason for planning such a large battery is to be able to support the neccessary current levels for the accelleration they have demonstrated. So they couldn't have just put a small battery in the car either.

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#93

Post by PeachPlum »

lucaspiller wrote: post #88
firebones wrote: post #70

Earlier quoted context omitted.

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 infrastructu…

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 b…

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.

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#94

Post by erik_seaberg »

blhack wrote: post #80
dboreham wrote: post #69

Earlier quoted context omitted.

I might have been skeptical too but I recently saw a _ship_ charged while docked for about 50min in Norway. Big plugs, two circuits and I think 600V. I took a picture that I could dig out for the curious.

Wow I would love to see that! Am I reading this right? A electric ship?

Working on a ship without power is like working in a basement during a blackout. Either you hook up to shorepower or you keep your genset running and everyone else near the dock has to deal with the smoke and noise.

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#95

Post by gamblor956 »

blhack wrote: post #80
dboreham wrote: post #69

Earlier quoted context omitted.

I might have been skeptical too but I recently saw a _ship_ charged while docked for about 50min in Norway. Big plugs, two circuits and I think 600V. I took a picture that I could dig out for the curious.

Wow I would love to see that! Am I reading this right? A electric ship?

No, a normal ship. To minimize pollution, most ports now require cargo ships to run their electrical systems off of harbor power while docked (instead of using the ship's own diesel generators).

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#96

Post by baddox »

nimos wrote: post #91
petre wrote: post #81

Earlier quoted context omitted.

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?

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#97

Post by baddox »

kumarvvr wrote: post #56
baddox wrote: post #48

Earlier quoted context omitted.

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 ch…

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 superch…

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.

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#98

Post by puranjay »

sametmax wrote: post #89
nimos wrote: post #30

The Tesla superchargers currently charge at around 2% a minute up until about 80% which is 40 minutes to hit 80%. Tesla is advertising 400 miles in 30 minutes which is 80% of the 500 mile capacity. What is so hard to believe about a 33% improvement over a couple year old tech that is a couple years from release? Here are current industrial/transportation/residential electric prices in US [0]. They think Tesla will pa…

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 agai…

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?

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#99

Post by johngrefe »

It breaks the "laws of batteries" until it doesn't. Has everyone lost their memory retention? Maybe everyone on HN is Software centric and hardware hobbyist. Fair enough. Big things coming in the battery space. https://news.utexas.edu/2017/02/28/goodenough-introduces-new...

Re: Tesla’s promises don’t compute with current physics and economics of batteries

#100

Post by LoSboccacc »

matt4077 wrote: post #43
ams6110 wrote: post #9

If this were any other company making such unsubstantiated claims that didn't have any basis in the reality of the underlying technology, they'd be getting roasted here.

You may be right. But there's nothing wrong with it. Tesla has done amazing things, and so has SpaceX. Yes, they're in the habit of being late. But neither has, as far as I can remember, ever produced "vapourware" they didn't eventually start selling. For a nice reference: see this comment sceptical of Tesla's capability to deliver this 100MW battery in Australia in 100 days. Which was just recently completed on time…

Gonna bet that being an hypercar they got the space for batteries by having a lower ground clearance

That said I’m still skeptical aboutthe figures given but not because of the batteries - it takes lot of engineering to keep a car togheter at those speeds: most of the components will be quite close to the limit of material science and tesla is not exactly known for its quality control pipeline.

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