[QUOTE=dai;52099089]*imagine if train cars had electric motors in the wheels to aid the motion of the full train? Even just a little bit of added push would be a massive relief on the main engine, speeding up starts and stops[/QUOTE]
Trains wouldn't really benefit that much for speeding up faster, and all cars already are equipped with brakes
[QUOTE=Goz3rr;52099768]Trains wouldn't really benefit that much for speeding up faster, and all cars already are equipped with brakes[/QUOTE]
Regenerative braking is a big thing for trains though.
[QUOTE=Morgen;52099784]Regenerative braking is a big thing for trains though.[/QUOTE]
Which is already a pretty common thing in Europe for the past two decades
[QUOTE=Morgen;52099784]Regenerative braking is a big thing for trains though.[/QUOTE]
KERS R&D is still steadily improving, and it's only a matter of time until consumer and commercial vehicles alike start seeing themselves outfitted with the tech. It would likely be limited to acceleration from a stop (brake for a light/sign, use that same kinetic energy to get moving again) but would absolutely increase overall MPG's, since initial acceleration is one of the biggest gas hogs.
[QUOTE=tratzzz;52099011]Probably going to be a cab-over, can't see Tesla making a conventional one, especially when they don't really require a giant engine room.
What means, probably going to be a lot less popular in the USA than it is going to be in Europe.[/QUOTE]
You're gonna need all that room for batteries to get this thing enough range, though, and rolling it out will include making sure that pretty much every major truckstop has charge points [i]at every single parking stall[/i].
If he does try to push an all electric, battery operated, bigrig on us I can only say 'Best of luck there buddy-o'. What would work best would be a small diesel engine producing about 500HP mated to a generator, which then drives traction motors, exactly as in freight locomotives. Those would allow for a transition period until the infrastructure to support a completely battery based rig is in place.
[editline]13th April 2017[/editline]
[QUOTE=Morgen;52099784]Regenerative braking is a big thing for trains though.[/QUOTE]
Most locomotives with dynamic braking just short the traction motors out across a resistor bank with powerful cooling fans keeping it from going fwoomf. There's nothing regenerative about it, though it wouldn't be difficult at all to replace or augment that resistor bank with a charging system for use in a bigrig.
[QUOTE=Sam Za Nemesis;52098973]Also announced a new conversible Tesla Roadster!
[media]https://twitter.com/elonmusk/status/852581046625345536[/media][/QUOTE]
I REALLY wanna see this.
It's also supposed to be performance focused right?
I love ICE cars, but I really want to see a performance focused Tesla. Lower weight hopefully with all that power?! MENTAL
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?
They can do more than one thing
I'm surprised no one is willing to convert some of Izuzu's work trucks to electric. These are super popular with small businesses who don't want larger trucks.
[t]https://my.mixtape.moe/uarqnd.png[/t]
[QUOTE=Whitefox08;52100504]I'm surprised no one is willing to convert some of Izuzu's work trucks to electric. These are super popular with small businesses who don't want larger trucks.
[t]https://my.mixtape.moe/uarqnd.png[/t][/QUOTE]
it's all about the mike tyson truck
[media]https://www.youtube.com/watch?v=c3KK4_qFp1M[/media]
[QUOTE=Del91;52099405]
They're already heavy as fuck, it'll help with traction. :v:[/QUOTE]
They should not be any heavier, weight limits are a serious concern for cab drivers when using interstates. Some drivers can be paid by how much material they deliver
[QUOTE=Whitefox08;52100504]I'm surprised no one is willing to convert some of Izuzu's work trucks to electric. These are super popular with small businesses who don't want larger trucks.[/QUOTE]
I'm not sure why people act like this doesn't exist yet. I live near a Scania factory and they use these kind of electric trucks to move trailers around the city:
[img]http://www.nc-nielsen.dk/Images/710/300/crop/elektrisk-terberg.jpg[/img]
And the local muncipality has added Nissan E-NV200's and electric Isuzu's to the maintenance fleet
[QUOTE=tratzzz;52099011]Probably going to be a cab-over, can't see Tesla making a conventional one, especially when they don't really require a giant engine room.
What means, probably going to be a lot less popular in the USA than it is going to be in Europe.[/QUOTE]
Conventional semi trucks are far more aerodynamic than cab-over trucks, which have all the aerodynamics of a brick. It'll probably look more like a giant Ford Transit
Aerodynamics is extremely important. It'll probably not be a big flat nose truck like in Europe.
[QUOTE=OvB;52105340]Aerodynamics is extremely important. It'll probably not be a big flat nose truck like in Europe.[/QUOTE]
Might even go as far to say it's probably the single most important thing when it comes to designing an electric semi.
[QUOTE=Morgen;52105349]Might even go as far to say it's probably the single most important thing when it comes to designing an electric semi.[/QUOTE]
Ehh.. not as much as you might think.
Moving 40 tons of shit up a 5-7% grade sucks up a substantial amount of energy. Aerodynamics matter, but the change in potential energy of a truck climbing 2500 feet is staggering. 80,000 pounds moving 2,500 feet straight up is roughly 75 kwh. That's not accounting for any losses of energy along the way, it's purely potential energy. Drag, rolling resistance, noise, heat, and everything else are going to make that even worse.
At a 5% grade, that's less than 10 miles of driving. Even if you made a truck with a drag coefficient of zero that's still going to be like pushing a barn through molasses.
This should be good...
[media]https://twitter.com/elonmusk/status/845290493130919936[/media]
I'm really interested to see what kind of range they can get with an electric semi. Electric motors shouldn't have any issues moving the load but I wonder if they'll have any gearing or just straight 1:1 like the model s. Gearing is really important with semis but I doubt they'd be able to use any off the shelf transmissions.
[editline]15th April 2017[/editline]
And while I guess a fast semi is neat, you really don't need it for hauling. You need ass loads of torque. Most trucks are speed limited anyways
[QUOTE=Del91;52107611]I'm really interested to see what kind of range they can get with an electric semi. Electric motors shouldn't have any issues moving the load but I wonder if they'll have any gearing or just straight 1:1 like the model s. Gearing is really important with semis but I doubt they'd be able to use any off the shelf transmissions.
[editline]15th April 2017[/editline]
And while I guess a fast semi is neat, you really don't need it for hauling. You need ass loads of torque. Most trucks are speed limited anyways[/QUOTE]
Model S/X is not 1:1, it is fixed geared.
[QUOTE=AGMadsAG;52107730]Model S/X is not 1:1, it is fixed geared.[/QUOTE]
This, at a 9.73:1 ratio. No difference between dual and single motor vehicles either I believe.
[editline]15th April 2017[/editline]
They tried having two gears in the Roadster but the torque would shred the transmission. A beefier transmission could be done in a truck though.
[editline]15th April 2017[/editline]
Though I'm not sure what the benefit would be of multiple gears in an EV, even in a semi? You still put the same amount of power in, it's just different gears allow for more torque or higher top speeds which we have plenty of already for a semi.
-snip the question's already been asked lmao-
[QUOTE=Morgen;52107740]Though I'm not sure what the benefit would be of multiple gears in an EV, even in a semi? You still put the same amount of power in, it's just different gears allow for more torque or higher top speeds which we have plenty of already for a semi.[/QUOTE]
Hill climbing.
See above for sloppy calculations about the kind of energy involved in going up a hill. Without gearing, that's a metric shitload of current. It doesn't matter as much for cars because they are going to have much higher power to weight ratios.
[QUOTE=Zephyrs;52108122]Hill climbing.
See above for sloppy calculations about the kind of energy involved in going up a hill. Without gearing, that's a metric shitload of current. It doesn't matter as much for cars because they are going to have much higher power to weight ratios.[/QUOTE]
But don't you need to still put the same amount of power in either way? If you need an additional 75 kW or whatever to get up a hill then you still to output it regardless of the RPM of your motor don't you? Gearing is useful with an engine to increase torque in a trade off for top speed. Iirc modern electric trains don't have transmissions, and instead have some sort of electronic system.
Wattage may be the same, but wattage comes from current * voltage. Torque comes from current. High torque = high current = very large cabling, lots of energy loss from resistance, and lots of heat.
I'm oversimplifying, but that's the general gist.
[QUOTE=Zephyrs;52108272]Wattage may be the same, but wattage comes from current * voltage. Torque comes from current. High torque = high current = very large cabling, lots of energy loss from resistance, and lots of heat.
I'm oversimplifying, but that's the general gist.[/QUOTE]
Okay but gearing doesn't increase your voltage? Upping the pack voltage from 400v to 800v would make sense for the semi.
[QUOTE=Morgen;52108307]Okay but gearing doesn't increase your voltage?[/QUOTE]
Wattage = voltage * current. If the total power output needs to be the same (ie the same wattage), and your current goes down, what needs to happen? The voltage needs to go up.
So yes, gearing will indirectly impact the voltage requirements.
[QUOTE=Zephyrs;52108455]Wattage = voltage * current. If the total power output needs to be the same (ie the same wattage), and your current goes down, what needs to happen? The voltage needs to go up.
So yes, gearing will indirectly impact the voltage requirements.[/QUOTE]
If you upped the pack voltage why would you change it when you went through different gears? Just keep it higher all the time. Torque isn't linked directly to the current. I still don't understand what the benefit of gears would be but I agree higher voltage would be useful.
Gears are a torque multiplier
[QUOTE=Del91;52108762]Gears are a torque multiplier[/QUOTE]
Yeah, which is something we will have in abundance for an EV truck.
[QUOTE=Morgen;52108542]If you upped the pack voltage why would you change it when you went through different gears? Just keep it higher all the time. Torque isn't linked directly to the current. I still don't understand what the benefit of gears would be but I agree higher voltage would be useful.[/QUOTE]
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]
[QUOTE=Morgen;52108920]Yeah, which is something we will have in abundance for an EV truck.[/QUOTE]
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.
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