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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

#31

Post by jepler »

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…

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.

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

#32

Post by toomuchtodo »

flor1s wrote: post #17
mtgx wrote: post #12

Earlier quoted context omitted.

Bingo. Not only that, but they may even rely on battery extrapolations for 2022, despite the truck and car being launched in 2019-2020. All they need is to break-even in the first year or two, and then they can make-up the profits from the improvement in battery prices. That said, the roadster itself will likely be profitable from day one. It's the truck that may not be. This is why Musk keeps getting ahead of everyo…

Meh, I think other companies just don't have the bravoure a man like Musk has. Also it helps if your company is a start-up and no heads will roll if you don't make a profit. Established companies don't have that luxury.

Established companies keep their stock price high by being conservative. Startups/growth companies keep their stock price high by pushing the envelope.

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

#33

Post by andreyf »

TylerE wrote: post #28
techbubble wrote: post #27

What would prevent the battery from having a segmented design so that multiple segments can be charged in parallel? Is there something about the chemistry that requires the entire vehicle battery to be a single unit?

At some point the size of the connector TO the vehicle is going to be the limiting factor.

In the case of a truck, that seems less likely -- surely they could come up with a design that hooks in 2, 3, 10 plugs the moment the truck is ready to dock.

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

#34

Post by will_hughes »

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 with unlimited supercharging)

The motivation for killing the unlimited free charging program seems to be partly people who would never charge at home, instead always charging at superchargers and often leaving cars parked for hours in busy locations, and the increasing commercial use of the supercharging network (by taxi companies).

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

#36

Post by mhermher »

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…

Did you seriously just compare rates by percentage across different batteries of probably different capacities? Anything to save face for Tesla I guess.

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

#37

Post by Animats »

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.

That requires a really big plug. Like this one, 400 amps at 440VAC, three phase.[1] There's a standard plug for plugging large ships into shore power. Truck stops are going to need high tension lines coming in.

[1] http://www.cooperindustries.com/content/public/en/wiring_dev...

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

#38

Post by extrapickles »

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…

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...

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

#39

Post by cperciva »

jepler wrote: post #31
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…

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.

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

#40

Post by nimos »

mhermher wrote: post #36
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…

Did you seriously just compare rates by percentage across different batteries of probably different capacities? Anything to save face for Tesla I guess.

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 %.

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