Tesla Powerwall 3 - Reviews

About Tesla Powerwall 3

The Powerwall 3 is Tesla's latest home battery. Its storage capacity is the same as the Powerwall 2, but it can supply more power and contains a built-in solar inverter. This makes it an all-in-one system that solar panels can be directly connected to.

Important features are:

• 13.5 kilowatt-hours (kWh) of usable energy storage
• 10 kilowatts (kW) of continuous output power (5kW in WA)
• 5 kilowatts (kW) charging rate
• Accepts up to 20kW of solar panels
• Operating temperature of -20 to 50 degrees
• Suitable for indoor or outdoor installation
• Flood resistant
• Can charge from solar during a blackout and potentially supply backup power for days or weeks.
• Cooling fans can get noisy enough to be annoying

You can order a Powerwall 3 and, according to Tesla at least, they should be available for installation any time now.

Do I Need A Powerwall 3 Or A Powerwall 2?

If you have solar on your roof and don't want more, a Powerwall 2—which is still currently available—is a lower-cost option. However, Powerwall 2 will not be available in the longer term.

If you don't have solar, a Powerwall 3 is a better choice because you won't have to pay for a separate solar inverter. If you have a small solar system you can add a second, Powerwall 3 connected solar system and leave your old one where it is. Alternatively, you can replace your old system with one large new one.

If you already have solar and really want to add a Powerwall 3, one or more can be AC coupled, provided your existing solar inverter's capacity is 5kW or less per Powerwall 3.

Some larger inverters can be used if they are specifically configured to ramp down during a grid outage, or as expansion packs become available, they will allow more AC coupled solar.

Another option is to disconnect your old inverter and connect your current solar panels to a Powerwall 3. This won't affect the Powerwall warranty however it may be technically difficult.

Rewiring of the existing array may be uneconomical and unless you're using the same installer, they're unlikely to want to touch a legacy system.

You can install a Powerwall 2 or 3 without solar if you like. Without DC-coupled solar, Powerwall 3 can be approved as an AC-coupled battery by your network company. However, you can't install a Powerwall 3 if you already have a Powerwall 2. They don't play together well and so aren't compatible, but they may be made compatible in the future.

13.5kWh Energy Storage

The Powerwall 3 has 13.5kWh of usable storage - exactly the same amount as the Powerwall 2. If that's not enough, up to four can be installed for 54kWh of storage. That will also give 40kW of power, and up to 80kW of solar panel capacity.

In 2025, Tesla says Powerwall 3 Energy Expansions will be available, a lower-cost method of increasing storage capacity. They will basically be Powerwall 3s without solar inverters that only add storage capacity. They’re the same size as the Powerwall 3 and designed to be installed behind it. We’re told they will be keenly priced, perhaps $1,000 cheaper than a Powerwall 3 and likely to have a lower installation cost.

10kW Continuous Power

While the storage capacity is the same as the Powerwall 2, the Powerwall 3's maximum continuous power output is much higher. While technically capable of providing 11kW of continuous power, in Australia it will be limited to 10kW or 5kW in Western Australia due to their grid connection requirements.

If a Powerwall 3 was discharged at a full 10kW then the 13.5kWh storage capacity of a brand new Powerwall 3 would be completely drained in just 1 hour and 21 minutes.  But most homes 13.5kWh is plenty to get through the average evening.

5kW Charging Power

While it can supply up to 10kW of continuous power, the Powerwall 3's battery storage can only charge at a maximum rate of 5kW. But if output is high enough, it can charge its storage at 5kW while also supplying up to 10kW of power to your home and/or the grid. So even if you have a lot of solar panel capacity, little or no solar power is likely to go to waste, provided the battery storage needs charging.

Expansion packs will offer an additional 5kW of charging capacity.

20kW Solar Capacity

The hybrid solar inverter in the Powerwall 3 can accept up to 20kW of solar panels. It also has three Multiple Power Point Trackers (MPPTs), which make it easy to install panels facing three different directions. If you want your panels facing more than three directions, that's possible, but you'll have to talk to your installer about your options.

When a battery is installed with solar, the system can exceed the normal oversizing limit for solar panel capacity and still receive the STCs that are part of the “solar rebate.” So, installing solar panel capacity that’s more than one-third larger than the Powerwall 3’s inverter capacity is not a problem. I recommend getting as close to 20kW of panels as possible to help keep the battery charged in the middle of winter and periods of bad weather.

Operating Temperature

The Powerwall 3’s operating temperature ranges from -20 to 50°C.  Your circumstances would have to be exceptional for the lower limit to be a problem in Australia.  The upper limit is also good for most homes, as no capital has hit 50°C so far.  But the Powerwall 3 can derate and reduce its maximum power output when the temperature is over 40°C.

Installation Location

Indoor or outdoor installation is fine for the Powerwall 3.  The lowest Ingress Protection rating of any part of a Powerwall 3 install is IP55 so it’s resistant to both dust and lashing rain.  Tesla says it can be installed in direct sunlight, but I recommend shade because heat isn’t good friend to batteries.

It will need to meet Australia’s strict standards for home battery location. Its cooling fans can make enough noise to be disturbing, so this should be taken into account.

The Powerwall 3 is designed for wall mounting.  Unlike the Powerwall 2 it can’t be placed directly on the ground as there’s a grate at the bottom of the unit through which it sucks air for cooling.  But it has two adjustable feet that ensure there’s enough of a gap.  If your wall can’t support the weight of a Powewall 3 for some reason – such as your house being made out of straw – this will complicate your installation.

Size & Weight

The Powerwall 3 is compact with only 2% more volume than a Powerwall 2.  It takes up considerably less space than an equivalent modular battery.  There’s also no need to find room for a separate solar inverter.  It’s 111cm high, 61cm wide, and 19cm deep.  If you are a very precise person who wants that in millimetres with a bullet point next to it, here you go:

• 1105mm x 609mm x 193mm

But it will also be necessary to mount an additional piece of hardware called a Backup Gateway 2.  This is a large box required for backup power that’s around half the height and width of the Powerwall 3 and is something that’s missing from every publicity photo on Tesla’s Australian site.  Its millimetre measurements are:

• 660mm x 411mm x 149mm

The weight of the Powerwall 3 is 130kg, so don’t drop one on your toes.  The Backup Gateway 2 is a much more manageable 20.4kg

Limited Flood Resistance & Don’t Listen To Tesla Marketing

To my surprise, the Powerwall 3 is flood resistant to 0.6m.  As it’s only 1.1m tall this means it can be halfway submerged and potentially be fine.  On the Tesla Australian site it says:

“It can maintain normal operation in cold temperatures, high humidity and flooding in 0.6 metres of water.” 

But this is wrong.  The above statement is directly contradicted by Tesla’s What to Do in Case of an Emergency page.  It can’t go for a swim and keep doing its thing.  It If there is any chance of floodwater reaching a Powerwall 3 it should be shut down immediately and, if touched by floodwater, only reactivated after Tesla support gives the okay.

Round Trip Efficiency

The Tesla Powerwall 3 datasheet says the efficiency of its solar inverter is 97.5% but doesn’t whether this is peak or average efficiency.  Either way, it’s a little less than the typical modern inverter, but not too shabby.  There are additional losses from charging and discharging the battery, so the total round-trip efficiency of storing solar energy in the Powerwall 3 and then discharging it to run your home is given as 89%. This means for every kWh of stored energy that comes out, 1.12kWh have to go in.  This isn’t great for a DC coupled battery, but it’s not too bad.

It Can Get Noisy

The Powerwall 3 datasheet says at 1m distance it will typically produce less than 50 decibels of noise.  An example of 50 decibels is a loud refrigerator or a typical air conditioner.  But when the fans are working hard it can produce nearly 62 decibels.  That’s louder than my handheld vacuum cleaner in eco mode.  It’s loud enough to be annoying and can potentially occur whenever the battery is working, including at night, so needs to be considered when deciding where to put it. The hotter it is, the harder the fans will work, so it will tend to be louder in summer.  

Backup Power

When the grid goes down the Powerwall 3 can supply backup power at the same continuous rate it’s normally capable of.  It can also charge from solar panels during a blackout, potentially allowing a home to run off backup power for days or even weeks, however fully off-grid applications aren’t supported.

The Powerwall 3 is a single-phase all-in-one battery, so if your home has single-phase power it can backup your entire home if desired.  But, while it’s simplest from an installation standpoint to back up the whole house, it’s not necessarily the best idea. Backup can be limited to only essential loads if desired, which can have the benefit of making your battery power last longer in an outage.

If your home has three-phase power the Powerwall 3 can also provide backup and charge from solar, but it can only backup appliances connected to the same phase it is on.  Essential loads can be moved to that phase.  Extra Powerwall 3s can be placed on other phases, but even if you have one on each phase, it won’t be possible to run three-phase appliances off backup power.

Starting Motors With Backup Power

When grid power isn’t available, home batteries can have a hard time starting electric motors, such as those in refrigerators or water pumps. This is because they can require six or eight times more current to get started than they need for normal operation.  

The Powerwall 3 can temporarily supply more power than its normal maximum continuous output of 10kw and this can be enough to get them going.  Tesla says it can start heavy loads rated up to 185 amps LRA.  As long as the Powerwall 3 is supplying little or no power to other devices, it should be able to start most motors that draw a continuous 6kW or less in normal use.  Because they vary in how much current they need to get started, the Powerwall 3 may even be able to get some motors going that have a continuous draw of 10kW.  

Not Currently Suitable For Off-Grid

While it can potentially provide backup power to a single-phase home for days or even weeks, Tesla does not currently recommend the Powerwall 3 for off-grid use. This may change in the future.

It Has An App

The Powerwall 3 has a monitoring app and it’s exactly the same as the Powerwall 2’s.  This might make you think you’re being fobbed off with old software, but it’s actually a good thing, because the Tesla Mobile App is definitely one of the better ones available for home batteries.  

Warranty

Provided its battery isn’t used to discharge electricity into the grid, the Powerwall 3 warranty will last for a full 10 years in normal use.  If it is used to send electricity into the grid – which will happen if it’s part of a VPP – then the warranty will last for either 10 years or until it has provided a total of 37,800kWh of stored energy.  The warranty also promises it will retain a minimum of 70% of its original capacity.

The Powerwall 3 must be able to receive updates over the internet. If it’s not online the warranty may be reduced to four years.   

The warranty requires you to follow the owner’s manual which states:

“The owner is responsible for ensuring the Powerwall system is operational; this can be confirmed by the white LED on the front of Powerwall 3, or in the Tesla mobile app.”

If the battery is not operational for an extended time it can be ruined. According to Tesla, if enough time passes without you noticing it’s not working, then the warranty doesn’t apply.  

You are also protected by Australian Consumer Guarantees and these can apply even after the written warranty has ended. 

Price

The Powerwall 3 battery costs $12,100 but requires a $1,500 'Backup Gateway 2', so you'll be paying $13,600. That is $1,500 more than the Powerwall 2. However, the Powerwall 3 comes with a solar inverter, which is conservatively worth at least $2,000. In addition to the hardware cost, you'll need to pay for installation.

If you buy more than one Powerwall, they can share a Gateway. 

Tesla has promised that the forthcoming Powerwall 3 Energy Expansion Packs will be keenly priced. These will add 13.kWh of storage to an existing Powerwall 3 installation.

Our Recommendation

We’ll need to wait for more Powerwall 3s to be installed in Australia before we can be sure it’s reliable.  However, given how well Powerwall 2 has performed in relation to most other battery systems on the market, we’re happy to recommend Powerwall 3 provisionally.