A newly published regulatory filing from the California Air Resources Board (CARB) 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.
For comparison, 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.
4680 Battery Specs
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.
To support the massive energy requirements of commercial logistics, 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.
Variant | Usable Capacity | Estimated Range* | Peak Charging | Peak Power |
|---|---|---|---|---|
Standard Range | 548 kWh | 325 Miles | 1.2 MW | 525 kW |
Long Range | 822 kWh | 500 Miles | 1.2 MW | 800 kW |
The Semi’s Efficiency
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 an astonishing 1.64 kWh per mile.
Again, 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.
Many legacy commercial manufacturers publicly doubted the feasibility of those numbers, but 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.
Why Cybercell?
When Tesla confirmed that they intended to use the Cybercell for the Semi, it raised many questions about using an expensive cell chemistry in such large quantities, versus cheaper, lower-performance LFP cells.
Building a battery for a Class 8 truck requires a delicate balance between maximum energy density to minimize the physical weight of the tractor and extreme thermal stability to handle commercial fast-charging.
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.
