7, 11 or 22 kW AC charging?

The right AC charging rating depends on the electrical supply, the installation limit and the vehicle’s onboard AC charger. Choosing a 22 kW wallbox does not mean every connected vehicle will charge at 22 kW.

What limits actual AC charging power?

During AC charging, the vehicle’s onboard charger converts AC electricity to DC for the battery. Actual charging power is constrained by the available supply, charging equipment, configured current limit and vehicle. Temperature, battery state and vehicle settings may reduce it further.

Start with these questions:

Is the site supply single-phase or three-phase?
What current is available on the intended charging circuit?
What is the vehicle’s maximum AC input, including its supported phases?
Will several vehicles or other loads share the available capacity?

Why are 7, 11 and 22 kW common comparison points?

They are useful catalogue categories, but the electrical configuration behind the number matters. The following calculations assume nominal voltage, a balanced three-phase supply where shown and a power factor of one. For three-phase power, 400 V is the line-to-line voltage and the current is per phase.

Common power class	Illustrative supply	Power calculation	Vehicle requirement
7 / 7.4 kW	230 V, single phase, 32 A	230 × 32 ÷ 1,000 = 7.36 kW	AC input able to accept this single-phase power
11 kW	400 V, three phase, 16 A per phase	√3 × 400 × 16 ÷ 1,000 ≈ 11.1 kW	Three-phase AC charging at the intended rating
22 kW	400 V, three phase, 32 A per phase	√3 × 400 × 32 ÷ 1,000 ≈ 22.2 kW	Three-phase AC charging at the intended rating

These are explanatory calculations, not specifications of an Ampvoya product. Use the selected model’s confirmed nameplate values and installation requirements when ordering.

Compare the application, not only the headline number

For overnight residential parking, begin with the required energy and the time available. For a workplace or hospitality project, consider dwell time, expected vehicle mix and how the site’s total electrical capacity is shared.

A higher-rated unit can be a reasonable specification where both the installation and vehicle support it. It should not be sold as an automatic speed increase for every vehicle.

Will a 22 kW wallbox charge an 11 kW car faster?

A vehicle limited to 11 kW AC cannot take 22 kW AC simply because the wallbox is rated for it. If the supply and configuration support the vehicle’s full 11 kW input, the onboard charger still sets that ceiling. A single-phase vehicle needs a separate phase-and-current check; do not compare total three-phase ratings alone.

How can a buyer estimate a charging window?

Divide the energy needed by the average charging power. For an illustrative 40 kWh requirement, 40 ÷ 7.4 ≈ 5.4 hours, 40 ÷ 11 ≈ 3.6 hours and 40 ÷ 22 ≈ 1.8 hours. These are ideal arithmetic comparisons assuming constant power and no losses. They are not measured charging times. Allow for the vehicle’s limits, battery conditions, charging losses and interruptions when planning a real window.

For multiple bays, use the site load-management example before assuming every vehicle can draw the full wallbox rating at once.

What belongs in the purchase specification?

Destination country and installation setting.
Nominal supply voltage, frequency and phase arrangement.
Required charging current and configured power limit.
Vehicle connector and expected vehicle AC capability.
Access control, networking and load-management requirements.
Electrical protection and documentation for the final configuration.

The Ampvoya EC-W300 is listed as a 7 kW, single-phase 230 V, 32 A Type 2 wallbox with a 5 m cable. Its OEM minimum order is 1,000 units. The 11 kW and 22 kW examples above are selection principles, not additional EC-W300 configurations.