7.4 kW, 11 kW or 22 kW charger: which should you choose?

The three most common powers

• 7.4 kW: single-phase, 32 A at 230 V. Works in most homes with a single-phase supply.
• 11 kW: three-phase, 16 A per phase at 400 V. Needs a three-phase supply.
• 22 kW: three-phase, 32 A per phase at 400 V. Needs three-phase and plenty of available power.

The car has a limit too

On alternating current (AC), the car’s on-board charger converts the energy for the battery. Many cars accept up to 7.4 or 11 kW on AC; fewer accept 22 kW. If your car only takes 11 kW, a 22 kW wallbox will charge it at 11 kW. And some cars stay below 7.4 kW on single-phase.

So before choosing, check your car’s manual or spec sheet for its maximum AC charging power and whether it accepts three-phase.

The installation decides the rest

A 7.4 kW wallbox draws about 32 A on single-phase, which weighs on a typical contracted power. If the rest of the house is using power at the same time, the main breaker can trip. There are two fixes: adjust the contracted power, or use a charger with dynamic load management, which lowers the charging power when the house needs it.

Moving from single to three-phase is possible, but it means changes to the contract and often to the installation. It only pays off if the car can use it.

So which one?

• House or apartment on single-phase, charging overnight: 7.4 kW is almost always enough.
• Home with three-phase and a car that accepts 11 kW: 11 kW can be worth it, especially if you drive a lot.
• Businesses and fleets with cars that move during the day: 22 kW can make sense, if the car and the available power allow it.

Many wallboxes let you cap the power in their settings. A common choice is to install a three-phase charger ready for the future and limit it to what the installation can take today.