Mercedes-AMG GT XX crushes EV endurance: 40,075 km at 300 km/h

AMG GT XX

Mercedes-AMG has a history of using extreme tests to push technology forward. The CONCEPT AMG GT XX is the latest proof. In August 2025, the electric prototype ran 40,075 kilometers at 300 km/h on the Nardò test track in just under eight days. The car set 25 long-distance records, including the 24-hour distance record for an electric vehicle—beaten fourteen times in one test week.

The AMG GT XX is more than a concept car. It serves as a rolling test lab for the AMG.EA platform, which arrives in production next year. The data, hardware, and endurance results from Nardò are shaping Mercedes-AMG’s future high-performance EVs.

This article breaks down the technology and market implications of the AMG GT XX in plain, direct terms.

Record-Setting Performance

• Distance covered: 40,075 km (the equivalent of driving around the Earth).
• Average speed: 300 km/h.
• Duration: 7 days, 13 hours, 24 minutes, 7 seconds.
• Records set: 25 long-distance EV records.
• 24-hour record: Broken 14 times during the event.

AMG used two cars for the test. Both maintained high speeds while stopping only for rapid recharging. This was not just a publicity stunt. The test validated cooling, aerodynamics, and charging strategies under maximum stress.

Axial-Flux Motors and Direct-Cooled Battery

The AMG GT XX uses three axial-flux motors. Unlike radial-flux motors in most EVs, axial-flux designs deliver higher power density. They are lighter, smaller, and more efficient at high output.

The direct-cooled battery keeps cells at optimal temperatures even under sustained load. Instead of waiting for heat to bleed through casings, coolant runs directly across cells. This cuts thermal build-up and supports fast charging with immediate power availability.

Together, this motor and battery setup enables sustained peak output without de-rating, a common issue in performance EVs.

Cooling System: Central Coolant Hub

At 300 km/h, heat management is as critical as aerodynamics. AMG designed a Central Coolant Hub (CCH).

Key features:

• Integrates pumps, sensors, and valves in one unit.
• Directs coolant to motors, battery, and electronics on demand.
• Reduces weight by removing excess hoses and brackets.
• Links to radiators and underbody cooling plates for efficiency.

The underbody cooling plate relieves radiator load, letting air shutters stay closed longer. This improves efficiency and drag reduction.

Result: full performance is available after both fast driving and fast charging.

Aerodynamics: 0.19 Drag Coefficient

At 300 km/h, 83% of energy goes into overcoming drag. AMG spent as much time tuning aerodynamics as power systems.

Highlights:

• Cd value of 0.19, a record for a wide-tired performance EV.
• Low-slung body with active air curtains and extended diffusers.
• Aero wheels with carbon claddings directing airflow differently at front and rear axles.
• Venturi underbody effect reduces rear lift without raising drag.

Each 0.001 drop in drag coefficient equates to a 90 kg weight saving at these speeds.

Charging at 850 kW

Endurance racing with EVs only works if charging is fast. AMG built a temporary High-Power Charging Hub with Alpitronic.

Key specs:

• Average charging rate: 850 kW.
• Peak current: 1,000 amps via CCS cable.
• Total hub capacity: 2.5 MW.
• Charging cycles simulated in Stuttgart before real testing.

The charging process was integrated into the race strategy. Cars braked with 0.6 g recuperation, recharged quickly, and relaunched at 300 km/h.

This validates megawatt-class charging for consumer EVs in the next five years.