CARB Filing Reveals Tesla Semi Battery Capacities

A newly published regulatory filing from the California Air Resources Board has revealed the battery capacities for both production variants of the Tesla Semi. The documentation confirms that the Long Range will use a large 822 kWh pack, while the Standard Range variant will use a smaller 548 kWh pack.

According to the CARB Executive Order, which certifies the powertrain design for the 2026 model year, Tesla is utilizing a Lithium-ion NMCA chemistry for the Semi. NMCA is a high-performance chemistry that delivers a significantly higher energy density than an equivalent weight LFP pack. The flagship Long Range model features an exact usable capacity of 822 kWh and is rated for a peak power output of 800 kW. The Standard Range variant scales the hardware down to a 548 kWh pack, generating 525 kW of peak power to achieve its targeted 325-mile range.

The estimated range for both variants is calculated strictly at the maximum gross combination weight of 82,000 pounds. Both variants are built around Tesla's 2nd-gen 4680 cell architecture, the Cybercell, and are capable of sustaining a 1,200 kW (1.2 MW) peak charging speed.

With the official battery sizes now part of the public record, the physical efficiency of the Tesla Semi can be calculated. To achieve 500 miles of range with an 822 kWh pack, the Long Range Semi operates at 1.64 kWh per mile. For comparison, the Model 3 achieves about 0.250 kWh per mile, about 6x less than the Semi. However, the Model 3 weighs just 4,000 lbs, compared to the Semi’s fully loaded weight of 82,000 lbs.

This efficiency for the Tesla Semi is a victory for Tesla's engineering team. When the Semi program was initially detailed, Tesla claimed the truck would consume less than 2 kWh per mile under a full load. The CARB filing definitively proves that Tesla has engineered a vehicle that significantly undercuts that 2 kWh threshold. Each and every decimal point below 2 kWh translates into massive efficiency increases for logistics operators.

By utilizing NMCA 4680 cells, Tesla ensures the battery pack can safely absorb the thermal load generated by the Megawatt Charging System. Pushing 1.2 MW of sustained power into the pack allows the Semi to replenish roughly 300 miles of range in approximately 30 minutes. This is exactly what will allow Semi fleet operators to maintain similar operational times, rivaling those of traditional diesel trucking.

For reference, the AWD, Long Range variants of the Model 3 and Model Y have about a 75-80 kWh battery, making the Long Range Semi’s pack about 10x larger in energy capacity.