Tesla Powerwall 3 Review
The review was published in Nov 2023. Latest update: April 2024.
In September 2023, numerous articles and photos of the Tesla Powerwall 3 emerged online. Soon after, Tesla officially announced the new Powerwall 3 and provided a brief description. More recently, in February 2024, the official datasheet was added to the documents section on Tesla’s website, so we can finally reveal the full specifications. Unlike the Powerwall 2, which is an AC battery system, the next-generation Powerwall 3 is an all-in-one solar and battery energy storage system, similar to the Powerwall+ (Plus) released in 2021, but more compact and far more powerful. However, while the new Powerwall 3 combines a solar inverter and battery storage into one simple system, it still requires additional components to enable its full potential.
See the detailed Tesla Powerwall 2 and Powerwall+ review here.
Full Specifications Revealed
At the All-Energy expo in Melbourne, Australia, I had the opportunity to see the new Powerwall and speak to a Tesla applications engineer. With the official datasheet now available, I can confirm the Powerwall 3 features six individual solar connections (6 x MPPTs), enabling a maximum 20kW of solar, or 3.3kW per MPPT. This makes for an impressive piece of equipment and a substantial upgrade from the older Powerwall Plus, which includes 4 MPPTs. Additionally, the new system is expandable with up to three optional 13.5kWh battery units able to be DC-coupled for a combined total of 54kWh. The Battery expansion units are still in development and have not been officially listed for purchase.
Powerwall 3 Key Features
Type: All-in-one solar & battery system (DC-coupled solar)
Capacity: 13.5 kWh (same as the Powerwall 2)
Scalability: Expandable up to 54 kWh with three additional 13.5kWh battery units.
Power rating: 11.5 kW continuous output.
Peak power: 185 Amps LRA (less than 1 sec)
Solar input: Up to 20 kW of solar via 6 x MPPTs (Six independent strings)
Solar Voltage: MPPT voltage ranges from 150 to 480V
Weight: 130kg (287 Ibs)
Available: from Feb 2024 - Online ordering is now available
Warranty: 10 years
Price: From US$8,400, including backup gateway (Same as the Powerwall 2). Excludes installation costs and any incentives or rebates. Additional 13.5kWh battery expansion unit $7300.
Download the official Tesla Powerwall 3 Datasheet
The Powerwall 3 Vs Powerwall 2
The most crucial difference between the various Powerwall systems is that the new Powerwall 3 is an all-in-one (hybrid) system, including a solar inverter. Unlike the Powerwall 2, which is an AC battery that needs to be installed with a separate solar inverter. The new Powerwall can be also used with most existing solar systems, including microinverters. For those familiar with the lesser-known Powerwall+ (plus), the Powerwall 3 is the essentially same type of all-in-one system but has been re-engineered with a much more powerful 11.5kW inverter and higher 20kW solar capacity.
One slight inconvenience the PW3 carries over from the Powerwall 2 is that it still requires the US$1,100 Gateway unit to enable backup power of critical loads during a grid outage. However, like the other Powerwalls, the PW3 has an alternative compact and rather ingenious Backup Switch to enable whole home backup. The more affordable Backup Switch, available in the US only, can be installed behind the utility meter or hidden inside a meter panel for a more streamlined solution. Since the PW3 has a much higher 11.5kW power rating, it is better suited for whole-home backup, although the amount of time the system can operate in off-grid mode is still limited by the battery capacity, so during poor weather, users will have to monitor the usage closely (unless they install multiple battery units).
Battery Efficiency
The existing Powerwall 2 is an AC-coupled battery system, meaning it does not contain a solar inverter but can be charged from any AC course, including an existing solar system or microinverters. On the other hand, both the Powerwall Plus and Powerwall 3 are DC-coupled hybrid systems that contain an inbuilt solar inverter and directly charge the battery from connected solar panels. Hybrid systems are more efficient since the battery is DC and the solar array is DC, so no DC to AC power conversion is required when charging from solar.
When we examine the power conversion in more detail, solar DC charging losses are typically less than 3%. In comparison, the AC-coupled Powerwall 2 requires power conversion from DC to AC at the solar inverter and then from AC to DC during charging, which results in a combined loss of around 7%. Lastly, the power conversion from DC to AC when discharging results in around 3% loss. The total charge and discharge losses are used to calculate what is known as the round-trip efficiency.
Powerwall 2 - AC-coupled battery = 92 - 93% charging efficiency
Powerwall 3 - DC-coupled battery = 96 - 97% charging efficiency
Comparsion chart of the Powerwall 2, Powerwall+, and Powerwall 3 features and specifications
Performance and Power
One of the most significant performance gains of the new Powerwall is the impressive 11.5kW continuous power rating (on-grid), which is around 60% higher than the 7kW Powerwall+. This much power would be overkill for smaller, efficient households. However, many modern all-electric homes with solar EV charging require a system with a high power rating, and this is where the extra grunt of the Powerwall 3 is ideal. It's worth noting an EV charger alone can draw from 7kW up to 9kW at full power.
The backup power rating is also 11.5kW, more than enough to support the power needs of most homes during a blackout. Interestingly, the peak power rating is not listed on the datasheet. I suspect it is fixed at 11.5kW continuous output and is not boosted higher using solar like the Powerwall+, which increases from 7kW to 9.6kW in full sun. However, the maximum surge Amp rating (LRA) is provided, as I examine in the next section.
Extract from the Powerwall 3 datasheet highlighting the battery charge power and peak Amp rating.
One notable limitation is the battery charge power is listed at only 5kW (AC), which means charging a flat battery will take a little under 2.5 hours. So, even with the solar maxed out at 20kW, the battery can only be charged at 5kW, meaning excess energy will either be exported or ‘clipped’ during sunny weather when the loads are low. This also reinforces the (still-to-be-officially-confirmed) LFP battery chemistry used in the PW3. Lithium Ferro Phosphate (LFP) cells do not tolerate rapid charging. However, regarding battery lifespan, I would consider this to be a positive, as it is well known that battery degradation rates are reduced at lower charging speeds, meaning longer life.
Peak Power Output
Powerwall 3 Power Ratings (*est)
11.5 kW Continuous Power
15.0 kW Peak Power (10 seconds) *
185 Amp Surge (less than 1 second)
While the peak power rating is not officially listed, we can make some assumptions based on what we know about the Powerwall 3’s little brother, the Powerwall+, which offers 10kW of peak power for 10 seconds. Additionally, we know the LRA (locked rotor amps) rating of the Powerwall 3 is an impressive 185A (initially listed at 150A), which is the maximum amps the inverter can supply (for less than 1 second) when starting a motor such as a compressor or large pump from a standstill. For clarification, the LRA rating, also known as the inrush current, can be described as the absolute peak amps or the maximum surge rating that can be sustained for less than 1 second.
Tesla Powerwall 3 battery continuous and peak power comparison chart.
The Powerwall+ has an LRA rating of 118A, equivalent to 28kVA at 240V. In comparison, the PW3 has a significantly higher LRA of 185A, equal to an impressive 44kVA at 240V. For those unfamiliar with kVA (kilo-Volt-Amps), the kW rating roughly equates to 0.8 x kVA. Therefore, 44kVA is approximately 35kW (or 17.5kVA at 120V). This substantial power output is more than enough to start almost any single-phase motor or clunky old HVAC compressor. However, unlike the peak power rating, which can generally be sustained for up to 10 seconds, the absolute maximum surge or LRA output is less than 1 second. It is worth noting the LRA is usually measured under standard test conditions at 25°C, so this will likely be lower at higher ambient temperatures or during sustained high continuous loads.
Pro tip: Using a load calculator is the best way to estimate the maximum peak and surge loads.
Powerwall 3 In-depth Analysis
Although the exposed cast aluminium housing of the Powerwall 3 looks and feels very solid, it is less attractive than the previous Powerwall 2. However, the new exposed outer shell is more about function than aesthetics, as the housing also acts as a massive heat sink to disperse heat and regulate the internal temperature. Additionally, it’s no surprise that the weight is around 15kg greater than that of the Powerwall 2, considering that a typical 10kW solar inverter weighs around this amount.
The size has changed; the new Powerwall 3 is 50mm shorter, 150mm narrower and 30mm deeper than the Powerwall 2. Considering the new PW3 also contains a solar inverter and is comparable to the much larger Powerwall Plus, the compact size is rather impressive. Aesthetics aside, one of the most exciting aspects is the high power rating, a remarkable 11.5kW continuous, making it one of the most powerful, all-in-one, single-phase battery systems available.
Powerwall 3 main specifications and features updated Feb 2024 - Image credit Tesla
Redesigned cooling system
Powerwall 3 active cooling system
Unlike the previous Powerwall 2, which relied on a complex liquid thermal management system, the new Powerwall uses a relatively simple active or fan-forced cooling system. The new design features a lower cold air intake, which takes advantage of natural convection to help cool the inverter. This works quite simply: as the large aluminium housing (heat sink) warms up, hot air rises, causing a natural flow of air, and the built-in fan increases this flow, depending on the temperature. Not surprisingly, this is how many solar inverters and all-in-one hybrid systems are cooled. However, Tesla has taken this one step further and integrated dual fans and a unique air duct system, which draws air along the front and rear of the battery unit.
New LFP cells
Besides being much simpler and less expensive, a logical reason why the cooling system has been re-engineered is due to the new LFP or Lithium Ferro Phosphate cells used in the Powerwall 3. Like many other battery manufacturers, Tesla has transitioned from Lithium NMC cells to LFP cells. The NMC or Nickel-Manganese-Cobalt cells previously used were similar to the batteries used in Tesla’s electric vehicles and require precise thermal regulation due to the limited operating temperature and increased risk of a thermal runaway at elevated temperatures. However, over recent years, LFP cell technology has advanced significantly and is much safer, longer lasting, and, most importantly, more thermally stable than NMC cells. This, in turn, means the cooling system can be simplified without any adverse effects. Importantly, LFP cells also contain no Cobalt. Issues around cobalt mining have been contentious, which is why most battery manufacturers, including Tesla, are working towards phasing out cobalt use over the next few years.
Powerwall 3 with the front cover removed showing the main internal features
More MPPTs but limited voltage range
While the specifications are impressive overall, one constraint is the slightly limited upper solar MPPT operating voltage. Solar panels are connected in strings, varying in length from as little as three panels up to 14 panels or higher. The longer the string, the higher the operating voltage. Most modern solar inverters operate in the 100 to 550V range, with a maximum of 600V. The Powerwall 3 specifications show a 150V to 480V operating (MPPT) voltage range and a maximum of 600V. This would result in slightly fewer panels per string. The 480V upper MPPT limit is the same as the Tesla solar inverter, suggesting it uses the same MPPTs. However, considering the PW3 contains an impressive six independent MPPTs, the limited upper voltage is not a major concern as the combined 20kW solar capacity is far greater than most other systems.
Systems designers can use the Photonik Solar String Voltage Calculator to determine the minimum and maximum string voltage.
Low MPPT input current rating
As with the Tesla solar inverter, another limitation is the 13A input current rating (per MPPT). Several 440W+ solar panels currently have a current (Imp) rating above 13A, which could result in some clipping of the solar output under ideal conditions. However, most residential solar panels operate in the 12A to 13A range, so it will not be an issue in most situations. Although, due to the ever-increasing panel power output, there are already some new panels rated at 500W with current ratings above 14A, making this a possible issue in the near future. While the MPPT maximum operating input current is 13A, the short-circuit current rating (Isc) is not much higher at only 15A. I expected the Isc to be 17A, as per the Tesla solar inverter.
Solution for high-current panels
Fortunately, there is one workaround which is noted in the fine print on the Powerwall 3 datasheet, which states, “Where the DC input current exceeds the MPPT rating, a jumper can be used to combine two MPPTs into a single input to intake DC current up to 26 A (Imp) can be implemented if high-current panels are used”. This essentially means the six solar MPPTs can be combined in pairs to create three high-current MPPTs rated at 26A and with a max Isc (short-circuit) current rating of 30A, which is more than enough even for large commercial 600W+ panels.
How much does the Powerwall 3 cost?
Tesla officially listed the Powerwall 3 for order online via their website in February 2024. Due to the additional features, we first assumed it would be more expensive than the Powerwall 2. However, the Price listed is the same as the current Powerwall’s discounted price of US$8,400, including the backup gateway which costs $1,100 if purchased seperately. However, the actual cost could be considerably lower once any incentives or rebates are factored in, making the new Powerwall more affordable than ever. Additional 13.5kWh battery expansion units are also available for an extra $7300 per unit.
When will the Powerwall 3 be available?
The Powerwall 3 is currently only available in the US via Tesla’s website. Unfortunately, countries outside North America, such as Australia, have to wait a lot longer. Tesla stated it will not release the new Powerwall 3 outside the US until late 2024.
Should you order the Powerwall 3?
If you live in North America, the short answer is yes if you require a powerful solar battery backup system in 2024. The Powerwall 3 appears to be a well-engineered, feature-packed system from Tesla. The impressive 11.5kW power rating, 20kW max solar input, and 6 MPPTs make this a great option for modern all-electric homes with solar EV charging. However, it’s not ideal for households with solar already installed. For those wanting to add battery storage to an existing solar system, the Powerwall 2 might be a better option. Although, if you’re considering upgrading your solar in the future, the Powerwall 3 has the advantage of 6 independent MPPTs and up to 20kW of solar. The cost is on par with the Powerwall 2, making it very reasonable since Tesla revised the price several times in recent years.
If you live outside the US and require a large, powerful solar battery backup system within the next 6 to 12 months, it is worth waiting for the Powerwall 3. However, several other high-quality solar battery systems are worth considering, which we highlight in our solar battery systems comparison chart.
