Where the property and car support three phases, 11 kW is a practical choice. A 22 kW wallbox helps only when the car accepts 22 kW AC and the full installation can supply 32 A on each phase. Check both before buying.
The car decides whether 22 kW is useful
Look for the car’s “maximum AC charging power” or “onboard charger” specification. Do not confuse it with the much larger DC rapid-charging figure.
An EV with an 11 kW onboard charger draws no more than about 11 kW from a 22 kW wallbox. The larger unit does not force extra power into the car. It simply offers a higher ceiling.
Some cars use single-phase onboard charging. On a three-phase supply, they may use only one phase. Check both maximum power and phase support in the specification.
The house must also support the load
At nominal European voltage, 11 kW uses about 16 A on each of three phases. A 22 kW unit uses about 32 A on each phase. This load sits beside heating, cooking and every other electrical demand.
An electrician must assess the service capacity, distribution board, circuit protection, cable route and voltage drop. The charger belongs on a suitable dedicated circuit. Local grid notification or approval rules may also affect the maximum power.
Hardware rating is not operating power
A 22 kW wallbox can often be configured to a lower limit. That does not mean the existing wiring is suitable for later 22 kW use. Any increase needs a fresh installation check.
Compare charging time with the correct formula
Useful battery energy divided by battery-side power gives an estimate. For AC charging, include efficiency: time = energy needed ÷ (input power × efficiency).
This example adds 54 kWh to the battery and assumes 90% efficiency:
| Available input power | Estimated time |
|---|---|
| 11 kW | 54 ÷ (11 × 0.90) = about 5 h 27 min |
| 22 kW | 54 ÷ (22 × 0.90) = about 2 h 44 min |
The second row applies only if the car can accept 22 kW for the session. Battery temperature, charging limits and vehicle controls can extend the time.
Both examples fit within an eight-hour overnight window. Faster is valuable only when the shorter window changes how you use the car.
Is 22 kW worth the extra capacity?
It can be useful for a 22 kW-capable car that returns with a low battery and leaves again soon. It can also serve a site where several cars charge in sequence.
It adds little when the car stays parked overnight or accepts only 11 kW. Higher connection capacity, larger equipment and grid work may cost more. Ask for an itemised installation comparison before deciding.
Future-proofing is a real reason only when the future demand is likely. Conduit space, a suitable distribution-board plan and a load-manageable wallbox may preserve options without energising the full 22 kW today.
When is 11 kW the better choice?
Choose 11 kW when the car supports it, the building has three phases and overnight charging covers your use. Under the stated 90% efficiency assumption, about 99 kWh is the maximum battery-side energy for ten hours at full input power.
Choose less than 11 kW when the home is single-phase, the service has limited headroom or your driving needs are small. A slower charger is not a compromise when it finishes before departure.
Choose 22 kW only after confirming four things:
- the current car or a credible future car can use it;
- the property has three phases;
- the installation can carry 32 A per phase; and
- local grid rules allow the planned load.
Frequently asked questions
Will a 22 kW wallbox charge every EV twice as fast?
No. It can be twice as fast only when the car accepts 22 kW AC and the installation can provide it. An 11 kW car remains limited to about 11 kW.
Can an 11 kW wallbox charge a 22 kW car?
Yes. The car can charge at the lower power. Charging equipment and the car communicate the available current before energy flows.
Does a 22 kW wallbox need three phases?
A 22 kW AC wallbox reaches that nominal power with three phases at 32 A per phase. The building supply and dedicated charging circuit must support that load.
Is 22 kW better for future-proofing?
Only if the extra electrical capacity has a realistic future use. A wallbox can be configured below its hardware maximum, but a larger circuit and grid connection may cost more.
