Choosing an EV charger: 7kW vs 22kW, single-phase vs three-phase
◢ Articleby David MillarMost Melbourne homes can't actually use a 22kW charger — and most drivers don't need one. Here's what the numbers mean, what your car can accept, and how to pick the right charger for the way you actually drive.
Picking an EV charger is one of those decisions where the numbers look simple — bigger is faster, faster is better — and the right answer for most Melbourne homes turns out to be the smaller one. Three things determine what you should actually buy:
- What electrical supply your home has (single-phase vs three-phase)
- What charging speed your car can actually accept
- How many kilometres you actually drive in a day
Get any one of these wrong and you'll either overpay for a charger that can't run at full speed, or under-spec a charger that bottlenecks your daily routine.
The numbers in plain English
Charging speed is measured in kilowatts (kW). The most common home charger options:
| Charger spec | What it means | km of range per hour |
|---|---|---|
| 2.4kW (3-pin power point) | Standard 10A wall outlet | ~10 km/hr |
| 7.2kW (single-phase 32A) | Dedicated single-phase circuit | ~40 km/hr |
| 11kW (three-phase 16A) | Dedicated three-phase circuit | ~60 km/hr |
| 22kW (three-phase 32A) | Dedicated three-phase circuit | ~120 km/hr |
(Range-per-hour figures use the rough rule of thumb that an average EV uses 18 kWh per 100 km. Your specific car will vary.)
For context: a typical Australian commute is 35-50 km per day. Most EVs have batteries between 50-90 kWh, giving 300-500 km of range when fully charged.
Step 1: What supply does your home have?
This is the gatekeeper. Most older Melbourne homes have single-phase supply, which physically caps you at 7.2kW (the maximum a single 32A circuit can carry).
To install an 11kW or 22kW three-phase charger, you need three-phase supply. Either your home already has it, or it doesn't.
How to tell what you have
Open your switchboard and look at the consumer mains coming in. Three black or black/red/blue cables coming in = three-phase. Two cables (one active, one neutral) = single-phase. You can also look at your meter — three-phase meters are visibly larger and have more cables coming out.
If you're not sure, a safety inspection is the easiest way to find out — we tell you what you have and what your spare capacity looks like.
Can I upgrade to three-phase?
Yes, but it's a meaningful job. We coordinate with your distributor (United Energy or CitiPower for most of Melbourne's east), they upgrade the supply from the street, we upgrade the consumer mains and switchboard. The cost depends on how far the supply has to be brought and whether there's existing infrastructure on your street.
For most homes, three-phase is justified by multiple high-load needs together — induction cooking + ducted air-con + EV charging + pool plant — not by EV charging alone. If EV is the only driver, a 7.2kW single-phase charger is almost always the better answer.
Step 2: What can your car actually accept?
This is the bit most people miss. Your car has an onboard charger — the device that converts AC power from your home wall charger to DC to put into the battery. The onboard charger has a maximum acceptance rate, and that rate caps how fast your car can charge regardless of what your wall charger can deliver.
| Car / model | Onboard charger spec |
|---|---|
| Tesla Model 3 / Y (current) | 11kW (three-phase) |
| Tesla Model S / X (current) | 11kW |
| BYD Atto 3 | 7kW (single-phase) |
| BYD Seal | 11kW |
| Hyundai Ioniq 5 / 6 | 11kW |
| Kia EV5 / EV6 / EV9 | 11kW |
| Polestar 2 | 11kW |
| Volvo XC40 / EX30 | 11kW |
| MG4 | 6.6kW (single-phase) |
| Mercedes EQE / EQS | 11kW (some 22kW option) |
| Porsche Taycan | 11kW (22kW optional, factory upgrade) |
Always check your specific model and trim — manufacturers change specifications between model years.
The implication is significant. If you buy a 22kW three-phase charger and your car's onboard charger is 11kW, you're paying for charging speed your car physically cannot accept. The 22kW charger will run at 11kW because that's the bottleneck.
A genuine 22kW use case is rare. It applies if:
- You drive a Tesla Model 3/Y or Model S/X with the upgraded onboard charger (where available)
- You drive a high-end Porsche, Audi or Mercedes with the 22kW factory upgrade
- You're installing for a fleet or commercial use where multiple cars rotate through
For everyone else: 7.2kW or 11kW.
Step 3: How much do you actually drive?
Run the maths on your real driving pattern.
Average commuter (40 km/day): A 7.2kW charger plugged in overnight delivers ~300 km in 7-8 hours. You're using 40 km, so you're net positive every charge cycle. 7.2kW is plenty.
Long commuter or heavy driver (80 km/day): Same charger delivers 300 km overnight, you're using 80 km, you're still net positive. 7.2kW still works.
Two EVs in the household sharing one charger: Now you might be running two 8-hour charge cycles overnight, and an 11kW charger gives you more headroom — you can fully charge both cars in one night. 11kW makes sense if both cars can accept it.
Heavy daily driver who wants top-up charging during the day: If you typically arrive home with low battery and want to be ready to leave again 2-3 hours later (e.g. childcare/school runs), a faster charger pays off. 11kW makes sense.
The rare 22kW case: The single situation where 22kW genuinely helps for residential is when you drive a car that accepts 22kW AND you regularly need to add 200+ km of range in under 2 hours. Almost no Australian driver actually does this regularly.
What to install: our recommendations
For 80% of Melbourne homes with EVs:
Install a 7.2kW single-phase charger on a dedicated 32A circuit. It's enough.
If you already have three-phase supply and your car accepts 11kW:
Install an 11kW three-phase charger. It's roughly the same install cost and gives you future-proofing.
If you're buying a Tesla Model 3 or Y and you have three-phase:
An 11kW charger matches the car. 22kW is overkill — the car can't accept it.
If you have three-phase and a high-end Porsche / Audi / Mercedes with the 22kW option:
22kW is genuinely justified. Install it.
What we install
We install all major charger brands across Melbourne's eastern suburbs:
- Tesla Wall Connector — works with any EV (Tesla or otherwise) via the included Type 2 plug, 7.2kW or 11kW capable depending on supply
- Wallbox Pulsar Plus / Quasar — popular for solar-PV integration
- Ocular IQ / Home — Australian-designed, full 22kW capable
- Evnex E2 — solar-aware, dynamic load balancing
- Schneider EVlink — commercial and home
We assess your switchboard capacity first, run a dedicated 32A circuit (or three-phase equivalent), install the charger, configure load management for solar integration where applicable, and lodge the Certificate of Electrical Safety on completion.
Often a charger install also surfaces that the existing switchboard is at end-of-life — particularly older Doncaster, Templestowe and Donvale homes where the board hasn't been touched in decades. We can quote both the charger and any switchboard work together so there are no surprises.
Book an EV charger install and we'll come out, assess your supply and switchboard, and quote both the install and any prerequisite work in one visit.