Lets work out the Tesla Semi-Truck Technical Specs

[lnpurnell]

Hi All!

As all of us here are aware, I think the reveal of the new design was impressive along with the range and 0-60 times. What I think we can all have a go at on this forum is to work out the technical specs of the Semi-Truck as I think these will no be disclosed for a while, it will help us all compare the specs with other proposed electric semi trucks that are in the pipeline so we have a fair comparison.

So I think there are several sections we need investigating:

• What kWh rating do you think the battery pack is in the 500 mile model? My assumption at this point is 500kWh
• It looks like they are using a lot of model 3 parts, do you think there will just be multiple model 3 battery packs in the floor plan or a special battery kit for the Semi?
• What will the motors likely be in kW? (they mentioned there are four of them)
• There was also some talk of Megachargers? do we have an idea of the KW rating of these chargers? Elon said that these would be powered by solar and tesla powerpacks (they would need to as utilities would cry at these power levels constantly switching on and off)
• They mentioned a 400 mile charge in 30 minutes, we can assume this is to 80% SOC, do we think this will be at 300-400 volts or do you think they will go to higher voltages like 800 volts (makes sense to go higher as the charger cables will be thinner, however this would make this system completely separate from the rest of the Tesla fleet and electronic parts will be much more expensive on 800v systems)
• The Megachargers seemed similar to the superchargers in physical size, was there an indication of a different connector to charge?

Please add to this list and we can get a good picture of what Tesla is offering !

Thanks!

Leigh.

 

[arnis]

As far as I understood, tractor has 4 Model 3 permanent magnet motors with no differentials, just reduction gears.
And ratio will definitely be way different. Truck max nominal speed will likely be 70mph.
This allows very different ratio compared to Model 3.
Also different reduction ratios between second and third axle for efficiency optimisation at different speeds.

Onboard vehicle, I believe drivetrain will run at the same voltage. 800V motors/inverters are hardly any better.
Nominally, each motor will be under comparable load while truck is cruising at 60mph compared to car
cruising at 60mph. Diesel cars have fuel consumption 5-7l/100km, trucks 30-40l/100km. Divide that load to 4 motors and
we get comparable nominal loads (especially with drag coefficient 0.36).
But while charging, 800V arrangement will help with charging current/conductors. AFAIK, It is possible to use 400V
electronics to charge 800V battery. Positive pin at +400V DC, negative not at 0V DC, but rather -400V DC.

Musk mentioned, that truck's drivetrain is redundant. Therefore I believe one pack failure (4 of them total likely, graphics
from event) will not result in breakdown on the side of the road. Same with motor. It's reasonable to believe that
odd packs serve left motors, even packs serve right motors. Or something similar.

BAMF will likely not have Model 3 battery packs. But it should be reasonable to use Model 3 pack modules.
Vehicle gross weight matters very little in terms of range. If fully loaded BAMF can do 500 miles, then with the same trailer
completely empty it might do 550 miles.

Megachargers we have been shown are actually just stalls. Charger is nearby. That same charger will likely be
able to charge passenger vehicles as well. Just not at the same stall. Trucks will have drive-through stalls with different plug(s).
Truck stalls will have priority over car stalls. Similarly like first Model S arrived per stall pair has priority over the second one today.
They will need to have powerpacks as load from the grid during peak time is not acceptable. Solar will just be there for statement,
but it will not be sufficient. I would remind the tweet when Elon hinted about 350kW as "child's toy". This is what he was talking about.
Like I said, cars could be charged at megacharger sites. Just not at the same bays. There is no reason one megacharger couldn't
serve 4 cars simultaneously.

I would like to get some estimations as well. How much energy is required for 0.36 Cd truck to drive 400 miles on flat road?

 

[deonb]

And ratio will definitely be way different. Truck max nominal speed will likely be 70mph.

Doubt it - part of the country has an 85mph speed limit. I don't think a truck will sell here that can't do 90mph at least when it's empty.

 

[timpierc]

Well some back of the envelope math would say the battery pack is probably around ~ 850kWh. The website is saying < 2 kWh/mile (not sure why they're throwing the 2 number out there, but ok). So let's say its in the high 1's, for shits and giggles we'll say 1.7 kWh/mile. 1.7X500 miles like they're claiming is an 850 kWh battery pack. For the 300 mile number (I'm guessing this is the city option for a semi usage) 1.7x300 would be 500 kwh battery.

 

[Laserbrain]

Have you guys seen the charge port? Kman has it on video - looks like the megacharger connectors got quadrupled compared to the supercharger:

 

[mongo]

Tesla tweeted the cut away of the motor/ battery. Looked like 4 separate packs, full width, double stack. I'm thinking each motor has its own pack and pair of charge pins as shown in previous post.

~200-250 kWh per sub-pack.

1.5 kW/mile GVW 60 MPH.

Charge at 300 kW per pack ~ 750 amps with liquid cooled cables on a support arm.

Non-aerodynamic 100% efficiency numbers
0-60 @ 80k in 20 sec is an avg of 654kW, and 3.6 kWh total.
5 % grade @ 65 MPH 80k is 518 kW add 97.5 for 1.5 kWh/mile, 615.5 kW output 825 HP net equivalent.

 

[ggnykk]

Tesla tweeted the cut away of the motor/ battery. Looked like 4 separate packs, full width, double stack. I'm thinking each motor has its own pack and pair of charge pins as shown in previous post.

~200-250 kWh per sub-pack.

1.5 kW/mile GVW 60 MPH.

Charge at 300 kW per pack ~ 750 amps with liquid cooled cables on a support arm.

Non-aerodynamic 100% efficiency numbers
0-60 @ 80k in 20 sec is an avg of 654kW, and 3.6 kWh total.
5 % grade @ 65 MPH 80k is 518 kW add 97.5 for 1.5 kWh/mile, 615.5 kW output 825 HP net equivalent.

Yea, the video on Tesla twitter page is so clear. It is a 12 packs in width x 4 times for sure. 48 battery packs total. Each pack could be just the standard pack that they use in Powerwall product or Model 3, or even the older cell in 100kwh Model S/X.

 

[Rowan256]

They said 1 mile can be done with less then 2kW
They said they have a 500 mile reach
2kW*500miles=1000kWh, So that sounds to me like a Megawatt powerpack, which is what I already estimated for quite some time.
Somehow I didn't expect all of it fitted in the truck alone, I thought some of it would be placed in the trailer. On top of that, I expected the trailer to be regenerating, that would have made jacknifing impossible for sure, on top of it, if the wind blows hard, trailers won't, or much harder, get blown over, I think the chances of that happening are still there with the current trailers.

 

[TaoJones]

Gah! This asshat is at it again. Between his latest article and the cretinous comments thereafter, I thought perhaps y’all might want to opine via the Comments section as well....

 

[Rowan256]

Gah! This asshat is at it again. Between his latest article and the cretinous comments thereafter, I thought perhaps y’all might want to opine via the Comments section as well....

"30 minutes of recharging time and the fact that the biggest recharger available is 600 kilowatts"
This and everything after it, doesn't make sense lol

 

[TaoJones]

"30 minutes of recharging time and the fact that the biggest recharger available is 600 kilowatts"
This and everything after it, doesn't make sense lol

You’re so right - and what’s even worse is evidently a number of folks (who have added comments) have taken a page out of the faux populist playbook and embraced being low information non-thinkers.

The article’s author might as well be the Pied Piper of Snowballs of Excrement. So to speak - the visual is better.

There’s mindless clickbait and there’s irresponsible drivel. That article seems to have accomplished both descriptors.

I realize this isn’t the first article of this ilk. However, it distinguishes itself with its collective myopia.

 

[Hertog_Martin]

I'm wondering if the 500 mile range on full load is based on the entire drive being at full load for 500 miles straight or if it's maybe an average based on the common 250 miles return trip they mentioned.

Perhaps the 250 to destination fully loaded will take 75% of the battery and with the 25% left you can drive back empty.

 

[mongo]

Yea, the video on Tesla twitter page is so clear. It is a 12 packs in width x 4 times for sure. 48 battery packs total. Each pack could be just the standard pack that they use in Powerwall product or Model 3, or even the older cell in 100kwh Model S/X.

Hi,
Would you take another look to verify/ correct my interpretation? It looked to me like 4 packs , the next set of frames drop the cab floor over it with fore/aft tube structures that make it look like more modules.

 

[arnis]

Doubt it - part of the country has an 85mph speed limit.

a) one country b) some states c) 85mph is not for trucks


Tesla Semi consumption at 60mph should be around 4,5-5x more than Model S. So 150-165kWh per 100 miles.
Based on Cd 0.36, same drag area and comparing Model S size vehicle diesel consumption with truck diesel consumption.

 

[miimura]

Hi,
Would you take another look to verify/ correct my interpretation? It looked to me like 4 packs , the next set of frames drop the cab floor over it with fore/aft tube structures that make it look like more modules.

To me it looks like 4 across, 6 thick, 2 sets fore-aft = 48 modules. Assume ~20kWh modules from the Model 3, then you get ~960kWh.

 

[mongo]

To me it looks like 4 across, 6 thick, 2 sets fore-aft = 48 modules. Assume ~20kWh modules from the Model 3, then you get ~960kWh.

This is the image I was going off. Could you post yours?

 

[Saghost]

Hi,
Would you take another look to verify/ correct my interpretation? It looked to me like 4 packs , the next set of frames drop the cab floor over it with fore/aft tube structures that make it look like more modules.

It definitely shows four discrete packs. The rest isn't as obvious. There are ribs in the packs that may or may not correspond to module locations which appear to make 12 sections in each one. The apparent aspect ratio suggests they are at least two cell tall if the cells are oriented vertically, but I saw nothing to suggest an actual height or cell orientation. (The ribbing might suggest three layers, if it has any signifigance.)

Combined with the redundancy comments and the weird 8 prong plus communication plug KMan filmed, I think maybe they are managed as 4 independent battery systems, each connected to a single motor and each DCFC'd separately. If they went that far, it probably has four separate AC charger modules on board, too, each feeding a single pack...

 

[mongo]

Rear suspension looks like a solid carrier with dual sided differential type access in the center that the motors mount to:

That pivots on an airbag suspension

 

[mongo]

It definitely shows four discrete packs. The rest isn't as obvious. There are ribs in the packs that may or may not correspond to module locations which appear to make 12 sections in each one. The apparent aspect ratio suggests they are at least two cell tall if the cells are oriented vertically, but I saw nothing to suggest an actual height or cell orientation. (The ribbing might suggest three layers, if it has any signifigance.)

Combined with the redundancy comments and the weird 8 prong plus communication plug KMan filmed, I think maybe they are managed as 4 independent battery systems, each connected to a single motor and each DCFC'd separately. If they went that far, it probably has four separate AC charger modules on board, too, each feeding a single pack...

Agreed. But not sure on the charger part. Would it have full 4 pack self charge ability? Seems like a corner case, since it would need a large source to recharge, and the routes should be well known so no out of charge situations. Maybe one charger that can link to any of the packs? 4:1 plug and selection via the pack contactors? With a service/ recharge truck, it could be eliminated entirely.
Lower cost of ownership to have a few megachargers and no truck charging.

 

[Ulmo]

This is the image I was going off. Could you post yours?
View attachment 261157

I see 4, for the 4 redundant drive trains (plug to wheel).