In this review of the Tesla Powerwall 2 we compare it to other leading battery brands, explore its features and potential installation costs in the UK.
The Tesla Powerwall 2, soon to be replaced by the Powerwall 3, is the market-leading domestic battery storage solution in the UK. Tesla recently celebrated over 600k Powerwall 2 installations.
Powerwall 2 offers flexible solutions to both users who are looking to recover excess solar energy and those who have no solar array installed. For those with solar, It allows homeowners to store more of the energy they generate from their solar panels, reducing reliance on the grid.
Battery storage is also increasingly popular among those looking to maximise the benefits of time-of-use energy tariffs, avoiding high electricity costs during peak times. This is called load shifting and is becoming one of the fastest areas of growth for the renewable industry.
It allows homeowners to store more of the energy they generate from their solar panels, reducing reliance on the grid.
Battery storage is also increasingly popular among those looking to maximise the benefits of time-of-use energy tariffs, avoiding high electricity costs during peak times.
But what makes the Powerwall 2 an industry leader? What features does it include, and how does it compare to rival battery brands?
In this article, we'll explain why it's not just the best-looking battery, but the best performing...
PS Heatable are Tesla-approved installers, we offer fixed prices with expert installation, so get a price for a Powerwall 2 here.
Tesla Powerwall 2 Specifications
Features: | Tesla Powerwall 2 |
Usable Capacity | 13.5 kWh |
How many can I install? | Up to 10 units (135 kWh) |
Round-trip efficiency | 89% |
Depth of discharge | 100% (you can use all the quoted capacity sizes) |
Continuous power output | 5 kW - with over boost function to 7.2kW for 20 seconds |
AC- or DC-coupled? | AC |
Tesla Powerwall 2 Usable Capacity
In terms of usable capacity, the Powerwall 2 can store up to 13.5 kWh of energy, which is sufficient to meet the energy needs of most households, especially during peak usage times or power outages.
The Powerwall 2 allows for the installation of up to 10 battery units, enabling a total capacity of 135 kWh. While this offers significant storage potential, it is likely more than what the average household requires.
A unique feature of the Powerwall 2 is that every time you install an additional unit, not only will you double the storage but you’ll also double the charge and discharge power.
For perspective, according to OFGEM, the average UK home typically consumes between 8-10 kWh of electricity per day.
Prefer video? Check out our video review of the Tesla Powerwall 2 below:
This means that even a single Powerwall unit could provide enough energy storage to cover 1 day of typical use, with reserve energy available to cover days with higher loads or for homeowners who wish to export energy to the grid for the highest rates.
The ability to expand the Powerwall system offers future-proofing for homeowners.
As energy needs evolve—due to the addition of new appliances, electric vehicles, or lifestyle changes—adding more storage capacity ensures that the system can adapt without requiring a complete overhaul.
Tesla Powerwall 2 Performance & Efficiency
The Powerwall 2 has a power output of 5 Kw (the amount of power it can supply or be charged with), which, while less than half of the next-generation Powerwall 3, is still sufficient for the majority of households. The added benefit of the over boost function to 7.2Kw allows for moments of high load to be kept within the envelope of the battery's power.
In terms of efficiency, the Powerwall 2 has a round-trip efficiency of 89%. This measures the energy lost during the storage and retrieval process, typically as heat. This does improve with the newer, Powerwall 3 model.
Regarding depth of discharge, which indicates the usable capacity relative to the battery’s maximum capacity, the Powerwall 2 boasts a 100% depth of discharge.
This feature ensures that users can utilise the entire capacity of the battery without risking damage or significantly reducing the battery’s lifespan.
Maximising the return on investment for homeowners, allows them to fully benefit from the energy they store, whether for use during power outages or to offset peak energy costs.
A handy feature of the Powerwall 2 is also the ability to set a minimum reserve charge in case of a grid failure.
Image showing the Tesla Powerwall 2.
Tesla Powerwall 2 Warranty
The Powerwall 2 comes with a 10-year warranty, a standard duration in the energy storage industry reflecting common practices among manufacturers. The warranty covers the product for all parts and all labour, which is rare for a battery product which would normally only offer a parts-only warranty.
Battery capacity naturally deteriorates over time, so most manufacturers guarantee a certain level of performance by the end of the warranty period.
In Tesla's case, the Powerwall is guaranteed to retain up to 80% of its original capacity after 10 years, a retention rate that is quite standard across the industry. This is monitored by Tesla’s servers.
However, Tesla distinguishes itself with its unlimited cycle coverage. A battery cycle measures the lifespan of the battery, with each full charge and discharge constituting one cycle.
Typically, warranties are tied to a specific number of cycles, meaning that once the designated cycle count is reached, the warranty expires.
With Tesla’s unlimited cycle coverage, there is no cap on how much or how often you can use your battery.
This ensures that, regardless of the number of cycles your Powerwall completes, the warranty remains valid for the full 10-year period.
This feature provides users with greater flexibility and assurance, knowing that their battery usage is fully supported without restrictions.
Related guides:
How much is the Telsa Powerwall 2?
The cost of installing a Tesla Powerwall 2 can vary based on individual requirements, but pricing through Heatable begins at £6,995. When factoring in installation, the total price starts at £7,695. This price also includes the gateway, a product which is required to be installed alongside the Powerwall 2.
This cost benefits from the new VAT regulations effective from February 1st, 2024, which exempt Powerwall installations from VAT charges, further enhancing its affordability.
Explore a Battery Storage Case Study: Check out an insightful Q&A session featured in one of our detailed case studies on battery storage. Hear directly from a Heatable customer in the UK and gain valuable perspectives on their experience here.
The image above features a Tesla Powerwall 3 installation performed by our team of Tesla-certified installers at Heatable.
How Does It Compare To The Powerwall 3?
The Powerwall 3 is already available in the USA and is set to launch in the UK in late summer 2024
The most significant upgrade from the Powerwall 2 to the Powerwall 3 is its all-in-one (hybrid) system design, which features a built-in solar inverter.
This enhancement eliminates the need for a separate inverter, previously necessary with the AC battery design of the Powerwall 2.
The Powerwall 3 is also compatible with existing solar arrays and microinverters, offering seamless integration for users with pre-installed solar systems.
This compatibility ensures that homeowners can easily upgrade to the latest technology without needing to overhaul their existing setup.
This integration is especially beneficial for new systems, reducing the total number of components required and simplifying maintenance and warranty processes.
With both the inverter and battery storage covered by Tesla, the world’s leading manufacturer in this space, users can enjoy streamlined support and peace of mind.
Additionally, the Powerwall 3 can deliver up to 11,000 watts of continuous power, more than double the capacity of its predecessor.
This substantial increase in power capacity provides robust support for your home, ensuring that more appliances can run simultaneously and that energy needs are met even during high-demand periods.
Overall, the Powerwall 3’s advancements in integrated design, compatibility, and increased power capacity make it a significant upgrade, offering enhanced performance and efficiency for modern energy needs.
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Next Steps For Your Battery Journey:
When planning to install battery storage for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their battery installation.
Get a Quote for a Tesla Powerwall Today
Without boasting you should get your battery storage installed with us, here's why:
Thousands of Happy Customers: We boast an average score of 4.9 on Trustpilot, outperforming the market leader.
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Tesla Certified Installer: Heatable is proudly certified and approved by Tesla to install the Powerwall.
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