Tesla Semi Walkaround & Discussion at ACT Expo w/ Dan Priestley

TL;DR

Tesla Semi director of engineering Dan Priestley explains the truck's aerodynamic design, integrated chassis, dual e-axle drivetrain, and TCO advantages over diesel.

Key Points

• 1.Aerodynamics account for ~50% of energy use, driving Tesla's design choices. The hard-mounted cab eliminates compliance gaps seen on traditional trucks, reducing drag and enabling a compounding efficiency effect that lowers required battery size, cost, and mass.
• 2.The Semi uses a unibody-style integrated chassis rather than a traditional twisting frame. Battery structure, frame rails, drivetrain, and front subframe all work together as one 'skateboard,' avoiding the torque-delivery inefficiencies of a longitudinal driveline.
• 3.Two battery variants balance range and payload: 500-mile long-range and a standard-range option. The long-range truck hauls a 45,000 lb payload and can be slip-seated with megawatt charging during driver rest breaks, achieving time and payload parity with diesel.
• 4.Tesla reuses components from Cybertruck and other models to control cost and improve reliability. Drive inverters and stators are shared with Cybertruck; the HVAC compressor comes from CyberCab; light modules and screens are also carried over from existing vehicles.
• 5.The twin e-axle setup provides 6x4 traction with 6x2 highway efficiency. The mid 'torque axle' has two independently driven motors for high-power events, while the rear 'efficiency axle' disconnects at highway cruise with zero windage losses.
• 6.Charging infrastructure is being built in lockstep with truck deliveries across ~50 sites. Tesla offers both a 1.2 MW V4 fast charger and a 125 kW base charger available to purchase online, leveraging the Supercharger team's experience deploying 80,000+ DC fast charging posts worldwide.