11 kW or 22 kW - which charging power is enough?

When choosing charging equipment, one question comes up right away: 11 kW or 22 kW? The bigger number sounds better, but in practice the upper limit of charging power is almost always set by the car itself. In this guide we explain what AC charging power consists of and how to choose according to your needs.

One phase or three phases?

AC charging power is a combination of current, voltage and the number of phases. Single-phase 230 V charging at 16 A produces 3.7 kW - the level of a regular household socket. Three-phase 400 V charging multiplies the power: 16 A on three phases means 11 kW and 32 A on three phases means 22 kW. The same logic runs through the whole Ampere Point range: for example the P35 portable charger is 3.7 kW (16 A, 1 phase), the Q11 is 11 kW (16 A, 3 phases) and the Q22 is 22 kW (32 A, 3 phases).

The car's on-board AC charger decides

In AC charging the car converts mains power for the battery with its own on-board charger - and it is this charger that sets the maximum power. If the car's on-board AC charger is 11 kW, the car charges at 11 kW even from a 22 kW device. Buying a more powerful device does not speed up charging unless the car supports it. That is why the Wallbox PRIME 11 kW is intended for cars with an 11 kW on-board AC charger, and the PRIME 22 kW for cars with a 22 kW on-board AC charger.

What does the power mean in practice?

As a rough guide, charging speeds are as follows:

• 3.7 kW adds about 15-20 km of range per hour - plenty for overnight charging and short daily drives.
• 11 kW adds about 50-60 km per hour - a typical daily drive recharges in a couple of hours and the battery fills easily overnight.
• 22 kW doubles this - but only if the car's on-board AC charger supports 22 kW charging.

What about fuses and the electrical connection?

Power also shows in the electrical connection. In simple terms: 3.7 kW charging runs through one phase at 16 A, i.e. within the limits of a regular household socket and its fuse. 11 kW requires a three-phase 16 A supply (for example a red CEE16A socket) and 22 kW a three-phase 32 A supply (CEE32A). The higher the charging power, the more is required of the connection and the fuses - which is why a fixed charging station is always installed by a qualified electrician who sizes the whole correctly. Wallbox PRIME stations also have current adjustment and dynamic load balancing that matches the charging power to the rest of your electricity use.

Recommendation: for most people the right choice is 11 kW

Most electric cars have an on-board AC charger of at most 11 kW, so an 11 kW device is the most sensible choice for the majority: it fills the car overnight and demands less of the connection than 22 kW. Choose 22 kW only if your car really supports it - or you want to be ready for your next car. If in doubt, check the on-board AC charger power in your car's specifications before buying.