Tesla Semi trucks are equipped with batteries of lower capacity, but their range remains unchanged

Tesla Semi: how battery capacity has changed and what it means

In recent weeks it has become clear that the main contender for using new 4680 cells – Tesla’s electric truck Semi – received batteries with lower capacity than originally promised. This was discovered after reviewing the company’s official certification documentation.

What regulatory documents say
- The California Air Resources Board approved specifications for two Semi models in mid‑April.
- Both versions are equipped with battery modules based on Tesla’s own 4680 cells, but with different capacities:
- High‑battery model – 822 kWh
- Lower model – 548 kWh

Why this matters
Elon Musk announced in December 2022 that the “first” Semi with an 800‑km range would have a battery of about 900 kWh (≈1.7 kWh/mile). In reality, the capacity turned out to be 10 % lower – 822 kWh. However, this did not affect the stated range: the truck still travels 800 km with a full load over 37 tons.

As the source explains, in March Tesla made aerodynamic and mass‑reduction changes:
- Reduced weight by more than 450 kg.
- Improved aerodynamics.

These changes allow achieving the claimed range even with a lower‑capacity battery.

Technical details
ParameterHigh‑battery model (800 km)Lower model (523 km)
Battery capacity822 kWh548 kWh
WheelbaseLongerShorter
Cab operation Longer, “habitable compartment” for long trips Shorter
Three‑motor power 1072 hp1072 hp

The control system allows engaging the rear axle only when needed:
- Front – provides traction at start, acceleration, and hill climbing.
- Rear – more economical for flat highway driving.

Conclusion
Tesla Semi does indeed use 4680 cells, but with slightly lower capacity than stated. Thanks to aerodynamic improvements and weight reduction, the company was able to maintain the promised range. This confirms that the new batteries can meet distance requirements without significant performance loss.