Do you need a 22kW three-phase EV charger? Usually not — 7kW covers almost everyone.
"Three times the power" sounds like an easy upgrade — until you learn that almost no EV sold in Australia can actually accept 22kW AC. Your car's onboard charger sets the ceiling, and for most popular models that ceiling is 7–11kW. Here's the overnight arithmetic that makes 7kW enough, what three-phase really costs if your home doesn't have it, and the few genuine cases where the bigger install is the right call.
Reviewed by the Mission Green Energy Team · Updated July 2026
Do you need a 22kW
three-phase charger?
For most homes, no. Almost every EV sold in Australia caps AC charging at 7–11kW through its onboard charger — a 22kW wallbox can't override that ceiling. A 7kW single-phase unit refills a normal day's driving in about an hour, and most of a full battery overnight.
Here's the one fact that settles most of this decision: the wallbox on your garage wall doesn't set your charging speed — your car does. Every EV has an onboard AC charger with a hard limit, and for most models sold in Australia that limit sits between 6.6kW and 11kW. Plug an 11kW-limited car into a 22kW three-phase unit and it charges at 11kW. Plug in a 7kW-limited car and it charges at 7kW — exactly as fast as it would on the cheaper single-phase unit. The extra capacity you paid for sits idle, every single night.
One thing before we go further: this page assumes you've already decided a wall charger is worth having at all. If you haven't, start with do you actually need a 7kW EV charger? — because for plenty of drivers, the honest answer to that question is "not yet" either. Below: the verified AC limits of Australia's popular EVs, the overnight arithmetic, what three-phase actually costs when your home doesn't have it, and the genuine cases where 22kW or three-phase is the right call.
"Three times the power" —
that your car can't accept.
The 22kW pitch quietly assumes your car can take 22kW AC. Check the spec sheets of Australia's most popular EVs and a different picture appears: 7kW, 6.6kW, 11kW. The onboard charger is the bottleneck, and no wallbox changes it.
AC charging — which is what every home wallbox does — passes through your car's onboard charger, a fixed piece of hardware with a fixed maximum. Here's what that maximum actually is for three of the most popular EVs on Australian roads, per their published specifications:
- Tesla Model Y — 11kW max AC. The onboard charger accepts up to 11kW, and only on a three-phase supply; on single-phase it tops out around 7kW. A 22kW wallbox adds nothing over an 11kW one (source: Tesla Owners Club of Australia; Zecar Model 3/Y charging guide).
- BYD Atto 3 — 7kW max AC. The onboard charger is single-phase, 32A: 7kW is the ceiling. On a 22kW three-phase wallbox it still charges at 7kW (source: EVSE Australia BYD Atto 3 guide).
- MG4 — 6.6kW max AC on most variants. The Excite 51, Excite 64, Essence 64 and X-Power all cap at 6.6kW single-phase; only the Essence 77 long-range supports 11kW three-phase AC (source: EVSE Australia MG4 guide; confirmed in a real-world Australian charging test).
Cars that accept a full 22kW AC do exist, but they're rare — historically the Renault Zoe, plus a handful of European models with optional upgraded onboard chargers. The federal government's own guidance makes the same point: the Type 2 connector supports up to 22kW, but the rate you actually get is limited by your vehicle's onboard charger (source: energy.gov.au).
So before any charger conversation, look up one number: your car's maximum AC charging rate. It's in the spec sheet, and it — not the wallbox brochure — is your real ceiling.
What 7kW actually does
while you sleep.
Forget "three times faster" for a moment and run the arithmetic. A car parked overnight has an 8-hour-plus charging window — and against that window, 7kW is not slow. It's more than almost anyone needs.
7kW × 8h ≈ 56kWh
Seven kilowatts flowing for an eight-hour overnight window delivers roughly 56kWh. Popular EVs carry usable batteries of about 50–80kWh — so one ordinary night at 7kW refills most of a full battery, from nearly empty.
A normal day: under 1 hour
The average Australian passenger vehicle covers roughly 30–35km a day (source: ABS Survey of Motor Vehicle Use). At typical EV efficiency of 15–18kWh per 100km, that's about 5–6kWh — which 7kW replaces in under an hour.
Even 300km fits overnight
A big 300km driving day uses roughly 45–55kWh at typical efficiency. That still fits comfortably inside one overnight window at 7kW. The days a 7kW charger genuinely can't keep up with are rarer than the sales pitch implies.
A 22kW wallbox is not
a "fast charger".
Part of what sells oversized home chargers is a confusion between two different technologies. The highway chargers doing 150kW-plus are DC. Every home wallbox — 7kW or 22kW — is AC. They are not points on the same dial.
Public fast and ultra-rapid chargers are DC: they bypass your car's onboard AC charger entirely and feed the battery directly. That's how a BYD Atto 3 — which accepts only 7kW AC at home — can take 80kW at a DC station (source: EVSE Australia). The onboard AC limit simply doesn't apply to DC charging, and the DC limit doesn't apply at home.
What this means for your buying decision:
- A 22kW home unit does not buy highway speeds. It's still AC, still routed through the same onboard charger, still capped at your car's AC limit. The "fast charging at home" framing borrows DC's glamour for AC hardware.
- The two legs do different jobs. Home AC is the slow, cheap leg — overnight, on your tariff or your solar. Public DC is the quick, expensive leg — for road trips. Sizing the home unit up doesn't shrink the road-trip stop.
- Judge home charging by the overnight arithmetic, not by comparison with a highway station. On that arithmetic, 7kW wins on value almost every time.
And if your home charging ever seems slower than these numbers suggest, the cause is usually settings, circuits or load management rather than the wallbox size — our guide to home EV charging problems and fixes walks through the honest diagnosis.
What three-phase costs
when you don't have it.
A 22kW charger requires three-phase power. Most Australian houses are single-phase — and getting three-phase isn't a bigger fuse, it's a network supply upgrade plus, usually, a new switchboard.
If your home is single-phase, the 22kW charger's price tag is only the start. To feed it you'd need your network distributor to upgrade the supply from the street, and in most cases a switchboard replacement to accept the three-phase connection — plus the electrician's labour to tie it all together. There's no single honest number for this: quotes depend on your distance from the street, your distributor's connection charges and the age of your switchboard, and they vary widely — routinely running into the thousands of dollars (see, for example, this Australian electrician's three-phase cost guide). Get an itemised quote for your address before believing any figure, including that one.
Now put the two halves of this page together: spending thousands on a supply upgrade so that a car with a 7kW onboard limit can keep charging at 7kW is the worst version of this purchase — real money for zero speed. Even for an 11kW-capable car, the gain over 7kW is a couple of hours off a full charge that was finishing while you slept anyway. Three-phase can absolutely be worth having for other reasons — big solar and battery systems, ducted air conditioning, workshops — and if that's the wider question you're weighing, read do I need three-phase power for a battery or EV charger? But as a purchase made purely to charge one EV faster overnight, the maths almost never lands.
When three-phase or 22kW
genuinely is the right call.
This isn't a "never buy it" page. There are real situations where the bigger install earns its keep — and if one of them is yours, we'll say so in the quote.
Three-phase already there + 11kW car
If your home already has three-phase power and your car accepts 11kW AC — a Tesla Model Y or MG4 Essence 77, say — an 11kW three-phase wallbox is a sensible middle: a real speed gain, no supply upgrade, modest extra cost. This is the honest version of the three-phase sale.
Multiple EVs or huge daily kms
Two or more EVs sharing one overnight window, or a vehicle doing a couple of hundred kilometres a day — regional commutes, rideshare, trades — genuinely benefit from more headroom. Here the arithmetic that says "7kW is plenty" stops holding, and bigger hardware starts paying for itself.
Switchboard upgrade happening anyway
If you're re-boarding or upgrading supply for other reasons — ducted air-con, a pool, a big solar-and-battery install — provisioning three-phase capacity while the walls are open is cheap future-proofing. The wiring is the expensive part; the bigger charger can come later, when a car that can use it does.
So — 7kW, 11kW,
or 22kW?
Here's the call we'd give a friend. And yes — full disclosure first: we sell and install EV chargers, so we make more when you buy the bigger one. We'd rather size it honestly.
For most single-car homes, a 7kW single-phase unit is the right buy. It refills an average day's driving in under an hour and most of a full battery overnight — and if your car's onboard charger caps at 6.6–7kW, as the BYD Atto 3 and most MG4s do, nothing bigger can charge it faster anyway. If you already have three-phase power and an 11kW-capable car, an 11kW three-phase wallbox is a fine middle step — take it. If you run multiple EVs, drive very high daily kilometres, or you're opening up the switchboard for other work anyway, that's when three-phase provisioning and bigger hardware genuinely earn their place. What we'd steer you away from is paying thousands for a supply upgrade and a 22kW unit that your car will never ask more than 7kW of. The cheaper install is usually the right one — and before any of this, make sure the answer to "do I need a wall charger at all?" is actually yes, then get the running costs right with the cheapest way to charge at home.
22kW & three-phase chargers
— your questions, answered.
For most Australian homes, no. A 22kW wallbox only ever delivers 22kW if two things are true: your home has three-phase power, and your car can accept 22kW AC — and almost no EV sold in Australia can. Most popular models cap AC charging well below that through their onboard charger: the BYD Atto 3 tops out at 7kW, most MG4 variants at 6.6kW, and the Tesla Model Y at 11kW. Plug any of them into a 22kW unit and they charge at their own limit, not the wallbox's. Meanwhile a standard 7kW single-phase charger delivers around 56kWh across an 8-hour overnight window — most of a typical EV battery — and an average day's driving takes under an hour to put back. Unless you already have three-phase power and an 11kW-capable car, run multiple EVs, or cover very high daily kilometres, the 7kW unit is the honest buy.
Usually not, and this is the detail the upsell leaves out. AC charging speed is set by the car's onboard charger, not by the box on your wall. A 22kW wallbox feeding a car with an 11kW onboard limit charges at 11kW; feeding a 7kW-limited car, it charges at 7kW — identical to the cheaper unit. Verified examples from manufacturer and retailer spec sheets: the Tesla Model Y accepts up to 11kW AC and only on three-phase supply; the BYD Atto 3 accepts a maximum of 7kW AC single-phase; most MG4 variants accept 6.6kW AC, with only the Essence 77 supporting 11kW. Before paying for a bigger charger, look up one number in your car's specifications: the maximum AC charging rate. That number — not the wallbox rating — is your real ceiling.
Yes, with room to spare — the arithmetic settles it. 7kW multiplied by an 8-hour overnight window is roughly 56kWh, which is most of a typical EV battery: popular models carry usable packs of about 50 to 80kWh. Day to day you need far less. The average Australian passenger vehicle covers roughly 30 to 35 kilometres a day, which at typical EV efficiency of 15 to 18kWh per 100km is about 5 to 6kWh — under one hour of charging at 7kW. Even a big 300km driving day uses around 45 to 55kWh, and a single overnight window covers that too. This is why charging speed at home matters far less than people expect: the car is parked all night anyway, and the real money question is what tariff or solar you charge on, not how fast the electrons flow.
If your home already has three-phase supply, a three-phase charger adds only modest hardware and installation cost, and 11kW three-phase charging is a reasonable option for cars that support it. If your home is single-phase — as most Australian houses are — a 22kW charger means a network supply upgrade from the street plus, in most cases, a switchboard replacement, on top of the charger and its installation. Quotes vary widely with your distance from the street, your network distributor and the age of your switchboard, and they routinely run into the thousands of dollars. Paying that so a car with a 7kW onboard limit can continue charging at 7kW is the worst version of this purchase. Get an itemised quote before committing, and weigh it against what the upgrade actually unlocks for your specific car.
There are a few genuine cases. First, if your home already has three-phase power and your car accepts 11kW AC — a Tesla Model Y or an MG4 Essence 77, for example — an 11kW three-phase wallbox is a sensible middle step: a real speed gain with no supply upgrade needed. Second, households running two or more EVs, where the overnight window is shared and extra headroom genuinely shortens the queue. Third, very high daily driving — regional commutes, rideshare or work vehicles covering a couple of hundred kilometres a day — where faster top-ups between shifts matter. Fourth, if you're upgrading your switchboard or supply anyway for other reasons, such as ducted air conditioning, a pool or a large solar and battery system, provisioning three-phase capacity while the work is being done is cheap future-proofing. Outside those cases, the 7kW unit does the job.
Different technology entirely, and mixing them up is what sells oversized home chargers. Public fast and ultra-rapid chargers are DC: they bypass your car's onboard AC charger and feed the battery directly, which is how a BYD Atto 3 that accepts only 7kW AC at home can take 80kW at a DC station. No home wallbox — 7kW or 22kW — is a DC fast charger. Home AC charging is the slow, cheap leg of EV ownership, done overnight while you sleep; DC fast charging is the quick, expensive leg for road trips. Buying a 22kW home unit does not buy you highway charging speeds, because the bottleneck is your car's onboard AC charger either way. Judge a home charger by overnight arithmetic and running cost, not by comparison with a highway station.
Where these figures come from.
Vehicle AC charging limits on this page are drawn from published specifications and were current as at July 2026. Model specs change between variants and model years — confirm your exact car's maximum AC rate in its spec sheet before buying a charger.
- Tesla Owners Club of Australia — charging guide (Model 3/Y 11kW three-phase AC limit)
- Zecar — Tesla Model 3 & Y home charging guide (11kW AC; ~7kW on single-phase)
- EVSE Australia — BYD Atto 3 guide (7kW single-phase AC limit; 80kW DC)
- EVSE Australia — MG4 guide (6.6kW AC on most variants; Essence 77 11kW)
- energy.gov.au — EV charging equipment (AC vs DC; onboard charger sets the AC rate)
- ABS — Survey of Motor Vehicle Use (average annual kilometres per vehicle)
- Electrx — three-phase upgrade cost guide (supply & switchboard cost factors)