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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

#71

Post by kalleboo »

kumarvvr wrote: post #66
nimos wrote: post #40

Earlier quoted context omitted.

Of course I did. Why wouldn't I? They are all battery PACKS. Maybe I didn't make that clear but I think that is a well known fact that Tesla batteries are made up of a collection of cells. You have 100 of battery X and you go to 1000 of battery X you can charge 10X more watt hours but the same %.

You are so right, the same percentage but at 10 times the current when compared to the former case. Then the question is "Do the superchargers allow for that much current?"

> Then the question is "Do the superchargers allow for that much current?"

They don't, which is why Tesla announced their plans to build new "Megachargers" https://www.teslarati.com/tesla-semi-megacharger-charging-po...

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

#73

Post by nimos »

bryanlarsen wrote: post #46
_ea1k wrote: post #15

Earlier quoted context omitted.

I can't take this author seriously. There is no way that Tesla is paying $1/kw. That is way past the retail rate, and I bet that they are paying much less than the retail rate in many of their markets.

They would if they were pulling straight from the grid. Go to your power company and ask how much it would cost to surge a mega watt of power at peak times. Those kinds of surges are really expensive to handle. Of course Tesla uses storage and solar to smooth their demand so that they can pay normal rates.

$1/kwh is a joke price. Peaking natural gas plants run at 20 cents/kwh on the high end. You can go buy a honda gas generator from home depot and run it for 1-2k hours and pay less than that per kwh.

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

#74

Post by nbanks »

cperciva wrote: post #55
kumarvvr wrote: post #53

Earlier quoted context omitted.

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.

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.

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

#75

Post by fencepost »

pfarnsworth wrote: post #35

Can't you just have multiple super-chargers charging different banks of batteries in parallel?

Not sure why this is getting downvotes, it seems like a blindingly obvious part of the system. As for power to the chargers and paying high premiums for surge loads, it's a real shame there's no technology that Tesla could use to accumulate and store power locally at stations with local storage capacity determined based on expected usage.

For that matter, just take the flat frame/battery pack of the current cars and make them replaceable slabs on rails. Charge each one independently or swap them out, though that'd probably be a service thing instead since you probably want to keep those trucks on the road as much as possible.

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

#76

Post by nbanks »

dreamcompiler wrote: post #67
excalibur wrote: post #44

I think most people are in agreement that the lithium ion battery is less-than-ideal technology that's due for replacement. And we have a number of innovations in battery technology vying for the opportunity. It's starting to feel a bit like Tesla's massive investments are only serving to further entrench the existing battery model. He's basically working to replace Big Oil with Big Lithium. There's no denying the be…

> He's basically working to replace Big Oil with Big Lithium. Electric cars need X kg of elemental lithium over the lifetime of the car. ICE cars need [on the order of] X kg of gasoline every 200 miles. This makes such a huge quantitative difference that comparing lithium mining to oil mining is almost pointless. In addition, lithium can in principle be recycled when the battery wears out. Gasoline cannot be recycled…

Some CO2 hydrogenation processes can produce liquid fuels which is kind of like recycling gasoline, but this is much more complicated than recycling batteries. It may still prove useful for fueling rockets or aircraft in a CO2 neutral way.

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

#77

Post by colmmacc »

will_hughes wrote: post #34
mcguire wrote: post #8

" Tesla offers free electricity to most of its Model S and Model X customers while paying almost $1 per kilowatt hour to produce it, Morsy said. That amounts to a subsidy of as much as $1,000 per car in 2017. " I realize that most people believe that Tesla and Uber will be able to continue subsidising their operations indefinitely, but it makes me very nervous.

The quote is wrong. First of all, supercharging was never 'Free' - it was a $1,000 addon option (at purchase, or $2,000 later) for a long while before finally being made standard. (The hardware was integrated into all models shortly after launch, but cost money to activate) Secondly, they killed the unlimited free charging program for new cars as of this year. (April, I believe was the cutoff for delivery of vehicles…

I got a new Model S in October and it came with free supercharging for life, because I had a referral code from another Tesla owner.

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

#78

Post by kalleboo »

mirimir wrote: post #3

It's an informative article, but the title is inaccurate. Tesla seems to be relying on plausible extrapolations for batteries in ~2020.

And if there's anyone who has good estimations to extrapolate the price and density development of batteries, it's the company that's building the world's biggest battery factory in close collaboration with one of the world's foremost battery manufacturers.

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

#79

Post by whamlastxmas »

colordrops wrote: post #50
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…

It's typical anti-Tesla propaganda.

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

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

#80

Post by blhack »

dboreham wrote: post #69
watchdogtimer wrote: post #19

> To meet Tesla’s claim of 400 miles in 30 minutes for a semi carrying 80,000 pounds would require its new Megachargers to achieve output of more than 1200 kW 1200 kw is a lot of power. That's the average amount of power used by 600 homes, or half of the output of a large wind turbine here in the Midwest, to charge a single truck. If they use a 440 V supply to charge it, that'd be over 2700 amps.

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?

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