The short answer For many South African homes, 7.4 kW is the practical sweet spot. An 11 kW charger is valuable where both the property and vehicle support three-phase charging. A 22 kW charger only delivers its full benefit when the supply and car can use it.
The number printed on a wallbox is its maximum available output. It is not a promise that every car will charge at that speed. The actual rate is limited by the lowest-capacity part of the chain: the electrical supply, the circuit, the charger setting, the charging cable, the vehicle’s onboard AC charger and, at times, the battery-management system.
This is why the biggest charger is not automatically the best charger. The right choice replaces the energy used in normal driving, fits the property and leaves a sensible margin for other loads.
The comparison at a glance
| Charger rating | Typical supply | Nominal current | Energy added in 8 hours | Best fit |
|---|---|---|---|---|
| 7.4 kW | Single phase | 32 A | Up to 59 kWh | Most homes and many EVs |
| 11 kW | Three phase | 16 A per phase | Up to 88 kWh | Three-phase homes and 11 kW-capable EVs |
| 22 kW | Three phase | 32 A per phase | Up to 176 kWh | High-capacity sites and 22 kW-capable EVs |
The energy figures are theoretical wallbox output. The battery receives less because charging has losses and the car may reduce power. Most home sessions also start with a partly charged battery and stop at a selected charge limit.
The vehicle sets the AC ceiling
A home wallbox supplies alternating current. The onboard charger inside the vehicle converts that AC power to DC for the battery. Its rating sets the car’s maximum AC charging speed.
A car limited to about 7 kW AC will take roughly the same power from a 7.4 kW, 11 kW or 22 kW wallbox. A vehicle that accepts 11 kW three phase can benefit from an 11 kW supply, but may take only about 7.4 kW when connected on single phase. Only selected vehicles accept 22 kW AC.
Check the exact model and derivative. Battery size, motor layout and equipment level do not reliably reveal the onboard charger rating. The DC fast-charging figure in a brochure is also not the AC figure.
7.4 kW works with the supply found in many homes
A 7.4 kW wallbox normally uses a 230 V single-phase supply at up to 32 A. That is a substantial continuous load, but it avoids the need for three-phase supply and matches the AC limit of many vehicles sold locally.
It can add close to 50 kWh during a typical overnight window after allowing for normal variation and losses. That is more than many drivers use in a day. The important question is whether the home has 32 A of genuine spare capacity while the geyser, oven, pool equipment and air conditioning are operating.
11 kW can be the balanced three-phase choice
An 11 kW charger normally draws about 16 A on each of three phases. It can charge a compatible vehicle faster than 7.4 kW and spreads the load across the phases. It may suit a property that already has three-phase supply, adequate capacity and a vehicle with an 11 kW onboard charger.
It is not normally available from an ordinary single-phase home supply. Installing an 11 kW-labelled wallbox on single phase does not create 11 kW charging; the output depends on the approved configuration of the exact model.
22 kW is useful only when the whole system supports it
A 22 kW wallbox normally needs 32 A on each of three phases. That is a large demand for a residence. It can make sense for a vehicle that accepts 22 kW AC, a business with several vehicle turnovers, or a future plan supported by the supply design.
For a car limited to 11 kW, the 22 kW wallbox will normally deliver no more than 11 kW. For a single-phase car, it may deliver only the power available on one phase. Paying for the larger wallbox, cable and switchgear therefore does not guarantee a shorter session.
How the three options affect charging time
| Energy to replace | At 7.4 kW | At 11 kW | At 22 kW |
|---|---|---|---|
| 15 kWh | about 2 h 20 min | about 1 h 35 min | about 50 min |
| 30 kWh | about 4 h 40 min | about 3 h 10 min | about 1 h 35 min |
| 50 kWh | about 7 h 45 min | about 5 h 20 min | about 2 h 40 min |
These planning estimates include a modest allowance for losses and assume the vehicle accepts the stated rate throughout. They are not promises for a particular car. Battery temperature, state of charge, charge limits and vehicle control can change the result.
Supply capacity matters as much as charger capacity
A charger must share the property’s supply with every other load. A 60 A single-phase service does not have 32 A spare merely because a 32 A breaker fits in the DB. Maximum demand and the real operating pattern must be assessed.
Where spare capacity is tight, the choices may include commissioning the charger at a lower current, scheduling charging, installing dynamic load management or applying for a supply upgrade. Load management is often the most practical option because the EV can use spare capacity when it exists and reduce demand when the home becomes busy.
Do not let future proofing become overbuilding
Useful future planning may mean selecting an adjustable wallbox, providing a suitable cable route, leaving DB space and allowing for metering or communications. It does not always mean operating at 22 kW today. A higher-rated charger can sometimes be commissioned below its maximum, but the fixed circuit must still follow the approved design and product instructions.
A practical selection checklist
- Confirm the exact vehicle’s maximum AC rate and phase capability.
- Estimate the energy normally used each day, not only the full battery capacity.
- Confirm whether the property is single phase or three phase.
- Assess supply capacity with major household loads operating.
- Check whether solar, backup power or an inverter changes the connection point.
- Decide whether fixed current, scheduling or dynamic load management is required.
- Design and test the dedicated circuit for the commissioned current.
Talk to NevGridSolutions
We can assess the vehicle, supply, distribution board and charging window before recommending 7.4 kW, 11 kW or 22 kW equipment. The aim is a charger that delivers a real benefit at the property, not unused capacity on a label.
065 556 4000 | info@nevgridsolutions.co.za | www.nevgridsolutions.co.za
Frequently asked questions
Will a 22 kW charger charge my car three times faster than 7.4 kW
Only if the vehicle accepts 22 kW AC and the installation can supply it. Many cars are limited to 7.4 kW or 11 kW AC.
Can an 11 kW charger work on single phase
Some product families have different configurations, but typical 11 kW operation requires three phase at about 16 A per phase. Confirm the exact model and instructions.
Is 7.4 kW enough for an EV with a large battery
Often yes. Home charging normally replaces the energy used that day rather than charging an empty battery from zero.
Can I buy a 22 kW wallbox and limit it for now
Sometimes. The charger must support an approved current limit, and the circuit and protection must suit the design. A setting does not correct unsuitable wiring.
Which option works best with solar
The best rate depends on available solar surplus, phase arrangement and control method. A charger able to adjust current can be more useful than one that simply has a high maximum rating.
Talk to NevGridSolutions
NevGridSolutions can assess your vehicle, site, supply capacity, DB, solar or inverter system and installation route before recommending the hardware.