During the recent customer delivery event of the Tesla Semi truck, Tesla announced that the vehicle will charge at a megawatt level.

That's not a surprise, because for large electric vehicles like Class 8 semi trucks, there really is no other way to quickly replenish the driving range, considering how big the batteries are (at least several hundred kWh).

According to the brief info, the company developed a new charging solution for 1+ MW (1,000+ kW) DC charging.

It's not said how high the power might go. We guess that it's just the starting point, as the CharIN's Megawatt Charging System (MCS) is potentially ready for 3,750 kW (3.75 MW) of peak power, assuming 3,000 A (3 kA) at up to 1,250 V (1.25 kV).

V4 charging cable

What we do know is that to achieve a 1 MW charging level, and maintain a thin/light/flexible charging cable, Tesla developed a new V4 charging cable, which uses a new immersion cooling technology.

As we can see in the image below, there are 12 wires (6 each way) and two coolant tubes inside the V3 Supercharging cable. That's enough to achieve a current density of roughly 14 A/mm2, (compared to 4 A/mm2 or so in the V2 version, without liquid cooling).

The new V4 charging cable has a significantly different setup with two arrays of thinner wires (instead of two groups of six thick wires previously), additionally immersed in coolant (on the return tubes). According to Tesla, this way the current density might increase to 35 A/mm2. That's 2.5x more.

Tesla Semi: 1+ MW DC charging

Through the use of the V4 charging cable, Tesla will be able to deliver a much higher current to the vehicle. Additional electrical losses will be quickly compensated for by the more intensive cooling.

But that's not the whole story. Charging power must be increased multiple times (four times if we compare a 1 MW to a 250 kW V3 Supercharging) and potentially maintained longer. This is why simultaneously Tesla will also more than double the voltage to about 1,000 V level (battery system and the charger's DC output voltage).

1 MW for Tesla Cybertruck

During the presentation, Tesla confirmed that the new 1+ MW charging system is coming to the upcoming Tesla Cybertruck.

Not only that, it was said that it's coming to Tesla Superchargers in 2023. Combining this with the clear sign "V4" it seems that we are talking about 1 MW V4 Tesla Superchargers.

1+ MW charging connector

We are not entirely sure about the charging connector. Tesla does not show the Semi's charging inlet and its new 1+ MW charging plug, as well as it does not say anything about the compatibility with CharIn's MCS, supported by a high number of manufacturers. It's a an open question.

Tesla's proprietary charging connector for cars in North America - recently opened and called the North American Charging Standard (NACS) - will rather not be able to withstand the 1+ MW load. The company says that it supports 1,000 V and should be good for 1 MW, but that's just an entry point for the heavy-duty vehicles.

In other words we might see two separate things:

Anyway, to handle 1+ MW charging (especially multiple stalls at once), Tesla intends to equip its fast charging stations with battery energy storage systems, based on the Tesla Megapacks.

Gallery: Tesla Semi

Tesla Semi specs (2022):

  • Fully loaded at 82,000 lbs (37,195 kg) Gross Combination Weight
  • Range: about 300 miles (483 km) or 500 miles (804 km)
    (two battery options)
  • Energy Consumption: less than 2 kWh/mile (1.24 kWh/km)
  • Estimated battery capacity (based on range and energy consumption): lower than 600 kWh or 1,000 kWh (1 MWh)
  • Acceleration 0-60 mph (96.5 km/h): 20 seconds (when fully loaded)
  • Speed up a 5% Grade: Highway speed limit
  • Powertrain: 3 independent motors (vs. four motors in the initial specs in 2017)
    - two electric motors for acceleration at the rear axle (with automatic disengage)
    - one electric motor for highway driving at the second axle (constantly engaged)
    - carbon-sleeved rotors just like Plaid
  • Fast Charging: up to 70% of range in 30 minutes
    Peak output: 1+ MW
  • Fuel Savings (est.): up to $200,000 over 3 years
Tesla MY2023 VIN Decoder  
 

Initial prices (at unveiling in 2017):

  • Expected Base Price (300 mile range) – $150,000
  • Expected Base Price (500 mile range) – $180,000
  • Base Reservation – $20,000
  • Expected Founders Series Price – $200,000
  • Founders Series Reservation – $200,000
    * Prices displayed in USD. International pricing will vary.
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