How to Choose a Home EV Charger: 7 kW vs 22 kW
Choosing a home EV charger is not simply a matter of buying the highest-powered unit. The right charger needs to suit your vehicle, your home’s electrical supply, where you park, when you usually charge and whether you want to use rooftop solar or lower-priced tariff periods.
A well-matched setup can make charging easier and give you useful control over energy use. An oversized or poorly matched charger may cost more without making the car charge any faster.
Start with your vehicle’s onboard AC charging limit
A home EV charger supplies alternating current, or AC, to the vehicle. The vehicle’s onboard charger converts that power to direct current for the battery, and its maximum AC input can limit the charging rate.
For example, connecting a vehicle that accepts a maximum of 11 kW AC to a 22 kW charger will not make it charge at 22 kW. Check the vehicle manual or current manufacturer specifications before choosing a charger. Battery state, temperature and vehicle settings can also affect the rate during a charging session.
7 kW versus 22 kW home charging
When a 7 kW charger may be suitable
A typical 32 A single-phase home charger operates at about 7 kW. This is a common option for homes with single-phase supply and can suit drivers whose vehicle is parked for several hours between trips.
The available output still depends on the vehicle, switchboard capacity, other household loads and the approved connection arrangement. A 7 kW rating is a maximum, not a promise of a fixed charging time.
When a 22 kW charger may be suitable
A 22 kW charger uses three-phase supply. It may suit a home that already has three-phase power, a vehicle that accepts higher-rate three-phase AC charging, or a household with more demanding charging needs.
Many vehicles accept less than 22 kW AC, so three-phase supply and a 22 kW wall unit do not automatically deliver a benefit. The likely charging rate should be checked against both the vehicle and the property before equipment is selected.
Tethered versus socketed chargers
A tethered charger has its charging cable permanently attached. It is convenient for regular home use because the cable is ready whenever you park, but the plug type and cable length need to suit the vehicle and parking position.
A socketed, or untethered, charger requires a separate cable. It can keep the wall unit neater and allows the cable to be replaced or changed separately, but you need to retrieve and store the cable each time.
Neither arrangement is automatically better. Consider where the charge port sits on the vehicle, how you park, whether another EV may use the charger and how the cable will be kept off the ground.
Solar-aware charging
A solar-aware charger can monitor available solar export and adjust EV charging to use some of that surplus. The result depends on when the vehicle is home, the solar system’s output, household consumption, the charger’s minimum operating current and how the monitoring equipment is configured.
Solar charging is not the same as simply choosing an off-peak or controlled-load tariff. Energex notes that an economy or controlled-load arrangement generally cannot use solar connected on the primary tariff to offset that charging load. Current primary-tariff options with dynamic or basic active management can support solar charging, subject to the charger, network arrangement and site design.
Electricity tariffs and charging times
Smart scheduling can move charging into selected time periods, but there is no single off-peak rate or charging window that applies to every home. Check available plans, time periods and eligibility with your electricity retailer before relying on a tariff feature.
Charging time should be estimated from the energy the vehicle needs, the vehicle’s AC limit and the power the installation can provide. Avoid judging a charger by a generic kilometre-per-hour figure because vehicle efficiency, battery state and driving conditions vary.
What load management does
An EV charger can be one of the largest electrical loads in a home. Load management monitors available capacity and can reduce charger output when the house is using more power elsewhere.
This can help coordinate charging with appliances, solar generation or multiple EV chargers. It does not remove the need for proper circuit design or automatically avoid every switchboard or supply upgrade. The charger, monitoring equipment and installation must work together.
Smart features and connectivity
Useful smart features may include:
scheduled charging;
solar-diversion modes;
adjustable charging current;
household load management;
app-based start, stop and monitoring;
charging history and energy-use reporting;
Wi-Fi, Ethernet or cellular connectivity;
access control for shared locations;
coordinated charging for more than one EV.
Check which features work locally if the internet is unavailable, whether ongoing connectivity is required and how software and firmware support are provided.
Comparing Zappi, Evnex and Tesla Wall Connector
Zappi
Current Australian Zappi models include 7 kW and 22 kW options, tethered and untethered versions, and ECO, ECO+ and FAST modes. Zappi can charge from the grid, solar or a combination of both, with app monitoring and scheduling. The appropriate model and monitoring arrangement still depend on the home’s supply and solar setup.
Evnex
Evnex offers single-phase E2 chargers rated up to 7.4 kW and the three-phase X22 rated up to 22 kW. Solar-smart operation, cable length and connectivity vary by model. Current options include Wi-Fi, with cellular connectivity on specified models, plus app scheduling and monitoring. Confirm the exact model rather than assuming every Evnex charger has the same features.
Tesla Wall Connector
The current Australian Gen 3 Tesla Wall Connector manual specifies adjustable output up to 32 A, support for documented single-phase or three-phase arrangements, Wi-Fi connectivity and power sharing between multiple Wall Connectors. It uses a tethered Type 2 handle. Check the vehicle’s connector and AC charging capability rather than assuming compatibility or charging speed.
Other suitable chargers
Other chargers may also be appropriate. Compare current Australian documentation, vehicle and connector compatibility, output, solar functions, communications, cable arrangement, manufacturer support and the features you will actually use.
When to get professional advice
Get advice before purchasing a charger if you are unsure about:
whether the home has single-phase or three-phase supply;
the vehicle’s onboard AC charging limit;
switchboard capacity or available circuit space;
the cable route and charger location;
solar monitoring or battery interaction;
controlled-load, time-of-use or managed connection options;
charging more than one vehicle;
Wi-Fi or communications at the parking location.
In Queensland, current Energex requirements include active device management for dedicated single-phase equipment above 20 A. A licensed electrical contractor can assess the proposed charger, switchboard, wiring, supply arrangement and charging location before confirming what is suitable.
If you are on the Gold Coast, KeenSpark Electrical can get help choosing and installing the right charger after assessing your vehicle, home and charging priorities.