Tesla Powerwall 3 review: what it does well, and what it will not do

The Powerwall 3 is a 13.5 kWh battery with the solar inverter built into it. That one change is most of the story: on a house with no solar yet, it replaces two boxes with one, and there is less on the wall to go wrong. We have put more than nine hundred Tesla Powerwall units on homes around Canberra and the surrounding NSW towns, and this is what we have learned about where it fits and where it does not.

This is a review by the people who install it. Take that both ways: we know the product at the switchboard, having installed it, and we sell it. So the parts worth reading are the limits.

What actually changed from the Powerwall 2

The Powerwall 2 was a battery. You put a solar inverter next to it. The Powerwall 3 is a battery with the inverter inside, and up to 20 kW of panels connect to it directly.

On a new solar-and-battery system that is a real simplification — fewer components, fewer connections, one warranty covering the conversion of sunlight and the storage of it. That case is the whole-system design, with no battery bolted on afterwards. On a retrofit to a house that already has a working solar inverter, the advantage is smaller, because you now own two inverters and only one of them is doing anything with the panels. That is not a reason to avoid it, but it is the reason a retrofit and a new system are different conversations.

The trade is repairability. Two boxes fail one at a time. One box takes the battery and the inverter out of service together.

The three power ratings, and why nobody quotes them properly

Powerwall 3 is sold at three continuous output ratings: 5 kW, 10 kW and 11 kW. Most pages about it print one number. That number is whichever of the three suited the person writing.

What it means at the house is simple enough. Continuous output is how much of your home the battery can run at once during an outage. At the top rating that is a normal evening with the oven on. At the bottom it is a normal evening with some care about what you switch on together. Which rating applies to your install is a question for the site inspection, and it is a fair question to ask any installer before you sign — including the one who fits it in Canberra.

⚠ The thing it will not do

Powerwall 3 will not run a house off-grid. It is a grid-connected battery that provides backup when the grid fails. Those are different products and the distinction is not marketing.

In practice: during a blackout it keeps your home running on stored energy, and if the sun is up your panels keep charging it. What it will not do is be the permanent power supply for a property with no mains connection. If that is what you are shopping for, a Powerwall 3 is the wrong battery and any installer who tells you otherwise has not understood the question. Enphase and the GoodWe ESA are the two other batteries we fit, and neither of them solves that either.

We say this on the product page too. It is the single most common misunderstanding we correct at the kitchen table.

Capacity, and the honest version of the expansion story

One unit is 13.5 kWh usable. A system takes up to four Powerwall 3 units, which is 54 kWh, and behind those it takes up to three Expansion units — seven objects and 94.5 kWh in total.

Almost nobody needs that. The number worth working out is what your house actually draws between sunset and sunrise, because that is the load a battery is there to cover. Working out how big a battery your house needs is a short piece of arithmetic and it is worth doing before you price anything. For most Canberra households one unit covers the overnight load with room left. The second unit does less than the first, and the third does less again — you are buying capacity that sits unused on an ordinary night to cover the nights that are not ordinary.

If you want more storage later, the Expansion Pack is the cheaper way to get it than a second full unit, because it is battery without a second inverter.

Three phase: a different unit, and not the one being installed yet

There is a three-phase Powerwall 3. It is a separate product with its own datasheet — 15.4 kW across three phases, four solar trackers, whole-home backup across all three. It is heavier and the wiring compartment carries a lower ingress rating than the battery.

What matters for a decision today is that it is not the unit we are putting on walls right now. If your house is three phase, that is a conversation about timing, and it is worth having before you commit either way.

Living with it

The app is the part people underrate before they own one and mention first afterwards. You can see what the house is drawing, what the panels are making and what the battery is doing, in the moment. Most people watch it closely for a fortnight and then stop, which is the correct outcome — a battery you have to manage is a battery that is not working.

Backup is the other thing. It covers every circuit in the house. An outage becomes something you notice because the neighbours went dark before you did.

The warranty, and the number under it

Ten years, unlimited cycles. The unlimited part is the one worth understanding, because most battery warranties are written the other way — a number of years or a number of full charge cycles, whichever you reach first.

A cycle-capped warranty quietly penalises the household that uses the battery hardest, which is the household that bought it for the right reason. If you fill and empty a battery most days, a cycle cap can arrive years before the calendar does. Removing the cap removes that trap. It is not a headline feature and it is one of the better things about the product.

A warranty covers the unit. It does not cover the installation. Ours is a separate promise: if your roof leaks after we have been on it, we pay $500 and we fix it. Two different things, and worth asking any installer to separate when they quote you. Who we are covers the second one.

Who it suits, and who it does not

It suits you if: your home is single phase, you have solar on the roof or are putting it there, and a meaningful share of your power gets used after the sun goes down. That is most households, and it is the case the product was designed for.

It suits you less if: you use most of your power during the day and export little, your roof array is small enough that the battery will rarely fill, or you want to leave the grid. The first two are arithmetic and worth checking before you spend anything. The third is a different product entirely.

We will tell you which of those you are. It costs us a sale sometimes and it costs less than installing a battery into a house that did not need one. The project pages show real jobs with the customer quoted on each, and every review we have is published with the score the customer gave.

On price: the federal discount comes off the invoice on the day, and what it is worth is set by capacity and install date, never by what you pay. The rebates page sets out both schemes, the federal programme has its own page, and the rebate finder works out your own configuration. If you are in the ACT, the ACT loan is the other half of it; if you are in the Illawarra, we install across Wollongong from Coniston. What comes off a Powerwall specifically is worked through separately.