One thousand amps. Thirty minutes. Four hundred kilometres.
In the last two weeks, megawatt truck charging stopped being a press-release slide and became something drivers actually plug in. Scania ran Italy's first MCS session on the Brenner corridor, Finland logged its first public MCS charge, Ekoenergetyka opened its first German MCS hub in Bochum, and Voltix opened a 1.5 MW-per-bay site in Vierzon, France. Here is the engineering math hiding behind those headlines.
The Megawatt Charging System (MCS) is the heavy-duty charging standard built so a long-haul electric truck can refill during the driver's mandatory break after 4.5 hours of driving. The new European sessions give us real numbers to check: Scania's 40 R accepts up to 750 kW at 1,000 A over MCS versus 375 kW at 500 A over CCS2, and Scania says that adds about 400 km in 30 minutes (Sustainable Truck & Van; TrasportoEuropa).
1. P = V × I: why MCS is a current story, not a voltage story
Power is simply voltage times current:
P = V × I
Scania's own numbers line up neatly. 750 kW ÷ 1,000 A = 750 V, and 375 kW ÷ 500 A gives the same 750 V on CCS2. In other words, the truck's pack voltage does not change between connectors. What doubles is the current the inlet, cable and contacts are allowed to carry.
That is why the standard's headroom is described in amps: MCS is designed for up to 3,000 A (TrasportoEuropa). The Alpitronic HYC1000 used in Italy outputs 150–1,000 V DC, so at its 1,000 V ceiling 3,000 A would mean 3 MW, but the cabinet itself is a 1 MW unit. Today the truck, not the charger, is the bottleneck.
Why not just raise voltage instead, like passenger cars going from 400 V to 800 V? Because the pack, inverter and every semiconductor on the truck would need re-rating. We covered that trade-off for cars in our video From 400V to 800V: The Silicon Carbide Revolution.
2. Energy per break: does "400 km in 30 minutes" add up?
Energy is power times time. Even if the truck held its 750 kW peak for the whole stop:
E = 750 kW × 0.5 h = 375 kWh (absolute ceiling)
Spreading 375 kWh over 400 km implies a consumption of ≤ 0.94 kWh/km. Real charging curves taper as the battery fills, so the energy actually delivered in 30 minutes is lower than 375 kWh, which pushes the implied consumption lower still. For a heavy tractor-trailer that is an optimistic figure, so the 400 km claim most likely assumes a favourable load, route, or a high average power with very little taper.
Also notice the 400 km matches the break logic: 400 km in 4.5 hours is an average of about 89 km/h. Scania is sizing the charge to one legal driving block, not to a full battery.
3. I²R: the heat problem that sets the real limit
Every milliohm in the cable, connector pins and inlet turns current into heat:
Ploss = I² × R
Take an illustrative 1 mΩ of total path resistance (an example value, not a measured spec):
- 500 A (CCS2 on the Scania): 500² × 0.001 = 250 W
- 1,000 A (today's MCS trucks): 1,000² × 0.001 = 1 kW
- 3,000 A (MCS design headroom): 3,000² × 0.001 = 9 kW
Doubling current quadruples the heat; tripling it again multiplies it by nine. That is why megawatt cables are liquid-cooled and why contact temperature sensing matters as much as the power electronics. A cable a driver can still lift by hand has to shed kilowatts of heat continuously.
Key point
MCS keeps truck pack voltage roughly where it is (around 750 V on the Scania) and wins by carrying more current. The price of current is I²R heat, which grows with the square of amps, so cable cooling and contact resistance, not the charger cabinet, decide how far toward 3,000 A the system can go.
4. The site: a truck stop that looks like a small substation
Voltix's Vierzon station opens with four charging points of up to 1.5 MW each, with plans for eight (electrive). Nameplate arithmetic:
4 × 1.5 MW = 6 MW → 8 × 1.5 MW = 12 MW
Nobody builds a 12 MW grid connection just to have every bay at full power at once. Sites share power between dispensers. The Alpitronic HYC1000 in Italy, for example, uses eight modules and allocates power dynamically in 62.5 kW steps, which is 16 steps across its 1 MW (TrasportoEuropa). Ekoenergetyka's Bochum hub similarly uses split configurations, with satellite MCS and HPC dispensers fed from shared power units (Ekoenergetyka).
The design question becomes a diversity factor: how many trucks really charge at peak at the same moment, and how long they stay above taper. That decides the transformer rating, the demand charge, and whether a stationary battery is worth adding to buffer the peaks. Volvo's FH Aero Electric, charged in Finland at up to 700 kW (Plugit), shows that even "1.5 MW" bays will mostly see 700–750 kW trucks for now.
To verify
- The MCS maximum voltage is often quoted as 1,250 V (which would make the 3,000 A ceiling about 3.75 MW). The sources above do not state it; to verify against the published SAE J3271 / IEC documents.
- Scania's 400 km in 30 minutes is a manufacturer claim; the load, temperature and charge curve behind it were not published. To verify.
- Voltix has not published the Vierzon grid connection rating or whether the site uses battery buffering. To verify.
- The 1 mΩ resistance in point 3 is an illustrative value for the formula, not a measured MCS cable spec.
Bottom line
Megawatt charging is arriving the way power engineers would predict: same pack voltage, double the current, and a lot of attention on heat and shared power. The trucks currently top out around 700–750 kW, so the chargers have headroom. The next real milestone isn't a bigger cabinet. It's a truck that can actually draw 1,500 A or more without its cable, inlet or pack overheating.
Sources: TrasportoEuropa, 29 Sep 2026 · Sustainable Truck & Van, 29 Sep 2026 · Plugit, Oct 2026 · Ekoenergetyka · electrive, 8 Oct 2026
