Tesla packs already run at ~400 volts all the time and will output up to 1300 amps. You can spread the power between several motors.
[editline]15th April 2017[/editline]
I mean gearing isn't really going to reduce the current required so you're going to need it either way.
[QUOTE=Morgen;52107452]This should be good...
[media]https://twitter.com/elonmusk/status/845290493130919936[/media][/QUOTE]
Doubt they can get a semi from 0-60 in less than 1.5 seconds.
Tesla really shouldn't advertise themselves as fast cars. Their fastest car does a full lap of Nurburgring in barely 9 minutes. That's mindbogglingly slow. A 1.8 liter Opel Corsa from 2007 is faster around the track.
They're not even as fast as they think at 0-60mph. A tuned GTR beats them by 0.8 of a second. That's a big gap. Tesla's are faster than most sports cars because they are sports cars. Not cannonballs. They're made to corner, not drag race. They're not made to get from 0-60, they're made to get from 60-100. Sports cars do that in 7 seconds. A Model S does it in 13 seconds.
[QUOTE=Morgen;52109018]Tesla packs already run at ~400 volts all the time and will output up to 1300 amps. You can spread the power between several motors.[/QUOTE]
It's not a problem with the motors. It's a problem with the wiring going literally everywhere else. The packs cannot sustain that sort of output indefinitely, and the wiring required to do so is nothing short of absurd.
[QUOTE=Morgen;52109018]I mean gearing isn't really going to reduce the current required so you're going to need it either way.[/QUOTE]
Uhhh.. we've been over this like 3 times now. You up the voltage instead of the current, then handle the increased RPMs with more aggressive gearing to step it down to low RPM and high torque again.
[QUOTE=Zephyrs;52109089]It's not a problem with the motors. It's a problem with the wiring going literally everywhere else. The packs cannot sustain that sort of output indefinitely, and the wiring required to do so is nothing short of absurd.
Uhhh.. we've been over this like 3 times now. You up the voltage instead of the current, then handle the increased RPMs with more aggressive gearing to step it down to low RPM and high torque again.[/QUOTE]
Higher voltage doesn't have to mean increased motor RPM, and you could simply handle it with a fixed gear still? The pack voltage won't change much unless you started engaging and disengaging extra cells or something odd.
[QUOTE=joost1120;52109083]Doubt they can get a semi from 0-60 in less than 1.5 seconds.
Tesla really shouldn't advertise themselves as fast cars. Their fastest car does a full lap of Nurburgring in barely 9 minutes. That's mindbogglingly slow. A 1.8 liter Opel Corsa from 2007 is faster around the track.
They're not even as fast as they think at 0-60mph. A tuned GTR beats them by 0.8 of a second. That's a big gap. Tesla's are faster than most sports cars because they are sports cars. Not cannonballs. They're made to corner, not drag race. They're not made to get from 0-60, they're made to get from 60-100. Sports cars do that in 7 seconds. A Model S does it in 13 seconds.[/QUOTE]
A Model S is a family sedan that weighs two tons and seats 7. A Tuned GTR is a car that's designed to go fast getting tuned to go faster. The reason Teslas are impressive when they can out-drag sports car's is because they are not supposed to be sports cars. They are fast Sedans and SUV's. They advertise it to break the stigma that EV's are slow golf carts.
It's advertising the potential of electric cars, that a tuned GTR can [I]only[/I] beat a 4,000+ pound luxury car by .8 seconds.
[QUOTE=joost1120;52109083]Doubt they can get a semi from 0-60 in less than 1.5 seconds.
Tesla really shouldn't advertise themselves as fast cars. Their fastest car does a full lap of Nurburgring in barely 9 minutes. That's mindbogglingly slow. A 1.8 liter Opel Corsa from 2007 is faster around the track.
They're not even as fast as they think at 0-60mph. A tuned GTR beats them by 0.8 of a second. That's a big gap. Tesla's are faster than most sports cars because they are sports cars. Not cannonballs. They're made to corner, not drag race. They're not made to get from 0-60, they're made to get from 60-100. Sports cars do that in 7 seconds. A Model S does it in 13 seconds.[/QUOTE]
Model S P100D does 0 - 100 MPH in 6.5 seconds even without Ludicrous plus mode.
Skip to 3:30
[video=youtube;EBXH7KJlsPE]https://www.youtube.com/watch?v=EBXH7KJlsPE[/video]
[QUOTE=OvB;52109159]A Model S is a family sedan that weighs two tons and seats 7. A Tuned GTR is a car that's designed to go fast getting tuned to go faster. The reason Teslas are impressive when they can out-drag sports car's is because they are not supposed to be sports cars. They are fast Sedans and SUV's. They advertise it to break the stigma that EV's are slow golf carts.
It's advertising the potential of electric cars, that a tuned GTR can [I]only[/I] beat a 4,000+ pound luxury car by .8 seconds.[/QUOTE]
A tuner GTR can ONLY beat a 4,000+ pound luxury car .8 seconds? 45% faster isn't exactly little.
A GTR might be designed to go fast, but it's only designed to accelerate 0-60 once. It's designed to go from 60-100, which it does very fast. Meanwhile the Model S is designed to go from 0-60 and it's not even faster than a sports car.
I get the whole point of it, but there's so many people fanboying over Tesla's because "they are as quick as a supercar", when they clearly aren't.
The 1.5 second GTR is an insane 2000hp+ road legal but barely driveable monster called the Alpha Omega, most tuned GTRs will not beat the Model S P100D (2.3 sec 0-60) and a stock GTR does "only" 2.7 sec 0-60.
[QUOTE=Morgen;52109196]Model S P100D does 0 - 100 MPH in 6.5 seconds even without Ludicrous plus mode.
Skip to 3:30
[video=youtube;EBXH7KJlsPE]https://www.youtube.com/watch?v=EBXH7KJlsPE[/video][/QUOTE]
I got a bit mixed up in mph and kmh. A high-end sports car does 100-200 kmh (124.3mph) in under 7 seconds. A Model S P85D does it actually in 12.6.
[editline]15th April 2017[/editline]
[QUOTE=AlexConnor;52109295]The 1.5 second GTR is an insane 2000hp+ road legal but barely driveable monster called the Alpha Omega, most tuned GTRs will not beat the Model S P100D (2.3 sec 0-60) and a stock GTR does "only" 2.7 sec 0-60.[/QUOTE]
GTR's tuned for drag races regularly beat 2 seconds.
[QUOTE=joost1120;52109300]I got a bit mixed up in mph and kmh. A high-end sports car does 0-200 kmh (124.3mph) in under 7 seconds. A Model S P85D does it actually in 14.7.
[editline]15th April 2017[/editline]
GTR's tuned for drag races regularly beat 2 seconds.[/QUOTE]
10.8 on the P100D.
Teslas aren't meant to be sports cars. They are fast simply because of the nature of electric motors. They handle kinda mushy and are clearly meant to provide a soft and comfortable ride rather than corner well. They have a low rollover risk simply because of the battery placement.
It's pretty much coincidental that Teslas are as fast as they are- sportiness was never a priority.
What remains to be seen is how the new Roadster will be on the road, though.
[QUOTE=FlandersNed;52100386]Doesn't Tesla have serious QC and service distribution problems right now?
Shouldn't they focus on fixing those things before they release the Model 3, let alone a semi or the roadster or a pick up?[/QUOTE]
Tesla is more than just one person working on a single thing at a time
[QUOTE=Morgen;52107740]This, at a 9.73:1 ratio. No difference between dual and single motor vehicles either I believe.
[/QUOTE]
The models with dual motors are geared differently in the front, to get better efficiency at highway speeds.
Tesla could make use of the same system for a semi, why have multiple gears, if you have multiple drivetrains that you could gear differently.
[QUOTE=purvisdavid1;52099048]That, and couldn't you slap a few solar cells on the top of the cargo containers they ship? Boom, you got a source of power on the road, all you gotta do is stop to rest and let the cells charge.
[/QUOTE]
Semi trailers and semi trucks are more often than not owned by separate companies. I work in a warehouse where we own every single trailer but we do not own a single truck nor employ a single driver, they're all contracted with Penski, a semi-truck driver service.
[QUOTE=purvisdavid1;52099048]That, and couldn't you slap a few solar cells on the top of the cargo containers they ship? Boom, you got a source of power on the road, all you gotta do is stop to rest and let the cells charge.[/QUOTE]
Several problems with this. Weight restrictions. It would only work on box trucks (flatbeds and container trailers are out). Plus the power output would be minuscule compared to what is required, so it wouldn't even work anyways.
I kind of want to see the new Roadster before anything else purely because of the war it would cause online between gearheads and techheads. :v:
[QUOTE=Zephyrs;52108959]It comes down to efficiency. There are still some efficiency losses when running electric motors at ludicrous RPMs. Those losses are just less of an issue than building around having to handle several thousand amps of current because you can make the motor casing massive and even run coolant through it fairly easily.
The question is if they are worth adding a transmission for or not. I'm honestly not sure that it is. It's a lot more worthwhile than doing it on a conventional car because the loads are so much more varied, and the power to weight ratio is so much lower, but it still might not be worth it. Even if it is, I can't see there being more than 3-4 gears at most. You really only need a low that can hit 50-65 climbing a decent grade with a full trailer, and a high for cruising on the flat/slight inclines.
[editline]15th April 2017[/editline]
I really think you are underestimating how much power it takes to climb a 7% grade with a full load. The cabling required to maintain that kind of power output at 4-500 volts is going to make the liquid cooled supercharger cables seem like speaker wire in comparison.
You're going to need very high voltages to cut down on cable size. Maybe they can just get away with rewiring the motors to use very high voltages while keeping the RPMs down, but there's issues with that too.[/QUOTE]
Using the numbers you gave
[IMG]http://i.imgur.com/Zn79x6m.png[/IMG]
That's 632 kW for a 40 tonne lorry going up a 7% grade at 55MPH. For a worst-case 400V battery that's 1580 Amps distributed among potentially as many motors as you have drive wheels, also potentially with independent cabling.
Chucking that into a resistance calculator you find that you need a 40 mm diameter single copper cable, which is [B]huge[/B] but can be bought. An 800V battery pack brings this down to 25 mm diameter.
Also bear in mind that chassis wiring does not necessarily run at the same voltage as the motors, and 650kW DC-DC converters are difficult to build but not at all impossible.
With a bit of gymnastics you can also run your motors off a lower effective voltage than the bus voltage, with something like [URL="https://en.wikipedia.org/wiki/Space_vector_modulation"]SVM[/URL] -- with very little additional cost, it's just a modulation scheme. They probably already do this to control power. So it's not strictly necessary to redesign your motor to run at a higher voltage. I'm not disputing that this is a difficult vehicle to build, but I don't think you've done enough calculations to reject it out of hand.
[editline]blah[/editline]
Oops, I typed 9.18 instead of 9.81. Only changes things by a few percent though.
Tesla have inverters on the drive unit anyway to convert the power from DC to three phase AC:
[t]https://i2.wp.com/electrek.files.wordpress.com/2016/06/tesla-drive-inverter.jpg[/t]
[QUOTE=Morgen;52112845]Tesla have inverters on the drive unit anyway to convert the power from DC to three phase AC:
[t]https://i2.wp.com/electrek.files.wordpress.com/2016/06/tesla-drive-inverter.jpg[/t][/QUOTE]
From the description it sounds like a normal [URL="http://www.irf.com/electronics/topology-fundamentals"]3-phase bridge[/URL]. With appropriate control they can produce any AC phasor at up to ~86% DC voltage (because trigonometry) for drive purposes and also provide rectification for regen braking. Because you can modulate the output voltage down without losing efficiency, you can run the batteries at as high a voltage as you want, as long as you don't explode the bridge, so chassis wiring is a bit lighter. They can't step the voltage [I]up[/I] though.
We got some new info from Musk today about the semi
[t]https://electrek.files.wordpress.com/2017/04/tesla-semi.jpg[/t]
[QUOTE]Musk is currently giving a TED talk today about his projects and after releasing the concept for his new ‘Boring Company’, he talked briefly about Tesla Semi.
He confirmed that the prototype is already working and he even got a quick test drive around the parking lot.
The CEO also [B]confirmed that the vehicle will be capable of long hauls[/B], which was previously uncertain due to its expected all-electric powertrain requiring an incredibly large battery pack in order to travel hundreds of miles with a payload.
[/QUOTE]
[url]https://electrek.co/2017/04/28/tesla-semi-elon-musk-teaser-image-all-electric-truck/[/url]
[QUOTE=Morgen;52161714]We got some new info from Musk today about the semi
[t]https://electrek.files.wordpress.com/2017/04/tesla-semi.jpg[/t]
[url]https://electrek.co/2017/04/28/tesla-semi-elon-musk-teaser-image-all-electric-truck/[/url][/QUOTE]
:speedfap:
[QUOTE=Morgen;52161714]We got some new info from Musk today about the semi
[t]https://electrek.files.wordpress.com/2017/04/tesla-semi.jpg[/t]
[url]https://electrek.co/2017/04/28/tesla-semi-elon-musk-teaser-image-all-electric-truck/[/url][/QUOTE]
It seems it is designed by Alienware.
[QUOTE=AntonioR;52161739]It seems it is designed by Alienware.[/QUOTE]
It looks similar to the Daimler Cascadia, which the guy leading the program at Tesla used to run the program for:
[t]http://icdn8.digitaltrends.com/image/daimler-trucks-north-america-prasentiert-brandneuen-freightliner-cascadia-970x647-c.jpg[/t]
Reading this thread just reminds me of the truck from Fortress and the auto-semi's from Logan.
On topic; maybe they could get around the battery problem by having the trailers packed with batteries underneath? I'm far from an engineer but that would seem like another way of doing it.
[QUOTE=Morgen;52161714]We got some new info from Musk today about the semi
[t]https://electrek.files.wordpress.com/2017/04/tesla-semi.jpg[/t]
[url]https://electrek.co/2017/04/28/tesla-semi-elon-musk-teaser-image-all-electric-truck/[/url][/QUOTE]
I just got a semi.
[QUOTE=madmax678;52163110]Reading this thread just reminds me of the truck from Fortress and the auto-semi's from Logan.
On topic; maybe they could get around the battery problem by having the trailers packed with batteries underneath? I'm far from an engineer but that would seem like another way of doing it.[/QUOTE]
I looked it up out of curiosity. I'm certainly not an expert on this shit (I'm an accountant!)' but what I've figured was:
A litre of diesel fuel has an energy density of 9.7kWh ([url]http://hypertextbook.com/facts/2006/TatyanaNektalova.shtml[/url])
Most semi-trailers today get something like 6.5 mpg, which converts to 36L/100km ([url]http://www.popularmechanics.com/cars/trucks/g116/10-things-you-didnt-know-about-semi-trucks/[/url]). I know that some Australian road trains have fuel consumption of 1L/1km, though.
Based on those figures, an electric truck of equivalent weight would require 36 x 9.7kWh, or roughly 360kWh, of battery storage to travel 100km. Some Tesla's only have 100kWh of storage to travel 539km, for comparison.
Granted, that's going to be off from the actual figure probably by a lot, I'm certainly not accounting for enough variables, and those calculations are probably flawed anyways. But if the Tesla semi is going to do anything like 300km hauls, it would need something like 1080kWh of battery storage to do. Eleven times more than the most storage you can get in a Model S. And 300km range is fairly pathetic for a semi.
[editline]29th April 2017[/editline]
[b]My calculations are most likely very flawed, but it's just a rough idea[/b]. If someone wants to do some actual calculations, I would actually be rather pleased to see them.
[QUOTE=BF;52163768]I looked it up out of curiosity. I'm certainly not an expert on this shit (I'm an accountant!)' but what I've figured was:
A litre of diesel fuel has an energy density of 9.7kWh ([url]http://hypertextbook.com/facts/2006/TatyanaNektalova.shtml[/url])
Most semi-trailers today get something like 6.5 mpg, which converts to 36L/100km ([url]http://www.popularmechanics.com/cars/trucks/g116/10-things-you-didnt-know-about-semi-trucks/[/url]). I know that some Australian road trains have fuel consumption of 1L/1km, though.
Based on those figures, an electric truck of equivalent weight would require 36 x 9.7kWh, or roughly 360kWh, of battery storage to travel 100km. Some Tesla's only have 100kWh of storage to travel 539km, for comparison.
Granted, that's going to be off from the actual figure probably by a lot, I'm certainly not accounting for enough variables, and those calculations are probably flawed anyways. But if the Tesla semi is going to do anything like 300km hauls, it would need something like 1080kWh of battery storage to do. Eleven times more than the most storage you can get in a Model S. And 300km range is fairly pathetic for a semi.
[editline]29th April 2017[/editline]
[b]My calculations are most likely very flawed, but it's just a rough idea[/b]. If someone wants to do some actual calculations, I would actually be rather pleased to see them.[/QUOTE]
The biggest thing you are missing here is the inefficiency of engines. A US gallon of gasoline contains 33.33 kWh, you don't see regular cars the size and weight of a Model S getting 110 mpg+ do you?
Maybe 30% of the energy from fuel is going to end up as kinetic energy being applied to the wheels. So if you take your 360 kWh figure and say 30% of it is actually useful energy in a regular truck then you're down to 108 kWh per 100km. Now suddenly you're 1080 kWh figure gives the truck a range of 1000 km.
[editline]29th April 2017[/editline]
Plus you can capture energy again on an electric semi with regen braking to further help things.
That semi looks amazing. I can't wait for the actual announcement in September.
Also I'd imagine the range will be pretty damn good. The electric concept works well for semi trucks, honestly. All the space used for the giant engine and fuel tanks can be replaced with stacked battery banks, and since the location of the batteries isn't as important as the location of the engine/fuel they can redesign the cabin to accommodate a more efficient and sensible battery location and design. I'd imagine we'll see something like racks of long batteries that run the entire length of the cab accessible from the 'hood', allowing for ease of access for servicing and replacement.
I'd also imagine companies purchasing these trucks will by default have unlimited access to superchargers and the new super-superchargers Tesla is planning, as well as the option to subscribe to/pay extra for 'quick battery refits' at Tesla locations, for dual-driver semis instead of pulling into a charger overnight while you sleep, you can have a Tesla service center replace the dead batteries with fresh ones in a few minutes and be on your way in roughly the same time as filling the gas tank.
Also considering Superchargers are strategically placed (or planned) along literally every single major US/Western European highway/interstate, I'd say Musk has been working toward this exact goal from the beginning.
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