Powervault
An independent look at Powervault's UK-built, modular P5 battery range, the successor to the long-running Powervault 3, from the technology behind it to how it fits alongside solar PV in a home.
- Modular, UK-assembled
- First-life lithium-polymer (NMC) cells
- 4 to 16 kWh usable, up to 20 kWh nominal
- British brand founded in 2012, designing and assembling its batteries in London
- Current flagship is the modular Powervault P5 (successor to the long-running Powervault 3), sold in four sizes with a usable AC capacity of 4, 8, 12 or 16 kWh; the 20 kWh figure sometimes quoted for the largest model is its nominal DC capacity, not what you can actually use
- Uses first-life lithium-polymer cells, a polymer pouch format built around NMC (nickel manganese cobalt) chemistry, different from the LiFePO4 cells Powervault itself now uses in its newer P4 and PVCompact products
- Has a long history of smart-tariff and grid-flexibility trials with suppliers including Octopus Energy, though exact partnerships have shifted over the years, so check current compatibility before buying
Independent coverage
This page reflects our own independent assessment of Powervault, not a sponsored placement. If we later add affiliate links to Powervault's site, any commission we might earn does not change what we say about the brand here.
Who is Powervault
Powervault is a British home battery storage company. It incorporated in 2012, and its headquarters are in London. There, it also designs and assembles its battery units rather than importing finished systems from overseas. Powervault is also one of the longer-running names in the UK home battery market. It has sold storage systems for more than a decade, through shifting solar incentives, energy prices and grid rules.
Powervault has also taken part in several grid-flexibility and smart-tariff research projects with UK energy suppliers and network operators. In 2017, for example, it partnered with Renault on an early “second life” trial. This reused recovered electric vehicle batteries in home storage units. That initiative dates from several years ago, however. It should not be assumed to describe Powervault’s current product line.
The Powervault product range
Powervault’s current flagship system is the P5, the modern successor to the long-running Powervault 3. It is sold in four sizes, with a usable AC capacity of 4, 8, 12 or 16 kWh. Powervault’s own current brochure also publishes a nominal (DC) capacity for each size: 5, 10, 15 and 20 kWh. The 20 kWh figure sometimes seen in marketing for the largest model is this nominal rating, however, not the usable capacity. Usable capacity tops out at 16 kWh on the P5.
According to Powervault’s current specification sheet, the P5 is available with a 3.6 kW or 6 kW inverter. This gives a maximum output of 2.3 kW on the smallest 5 kWh model, rising to 3.4 kW or 4.7 kW on the larger models. The maximum charging input is 2.8 kW on the smallest model and 5.6 kW on the rest.
Alongside the P5, Powervault also sells the larger-capacity P4 for bigger installations, with a usable AC capacity from 8 up to 24 kWh. It also offers the smaller PVCompact, with a usable AC capacity from 4 to 8 kWh. All three are current products, so the right choice depends on the size of system you need, rather than there being one standard Powervault battery.
4 kWh+
usable capacity on the smallest current Powervault P5 model
Unlimited
warranted cycles under the current Powervault P5 warranty
10 yrs
warranty, with a published end-of-warranty capacity guarantee
Key technology behind Powervault
The P5, Powervault’s successor to the Powervault 3, uses first-life lithium-polymer cells at a 100% depth of discharge. Lithium-polymer describes the cell’s physical form, a flexible pouch rather than a rigid cylindrical or prismatic can. The underlying chemistry inside that pouch, however, is NMC (lithium nickel manganese cobalt oxide). This is different from the lithium iron phosphate (LFP) cells now used by most newer home battery brands. Powervault has itself already switched to LFP cells for its other current products, the larger-capacity P4 and the smaller PVCompact. As a result, the P5 is now the one model left in its own range using the older NMC cells.
Powervault’s current specification sheet for the P5 gives a 10-year warranty with unlimited cycles. It also guarantees a minimum 70% state of health at the end of that period. This is an improvement on the roughly 6,000-cycle estimate published for the earlier Powervault 3.
Monitoring and scheduling run through Powervault’s own web-based Portal. This shows live and historical energy data, and lets you set charging schedules and usage priorities. Behind the scenes, “SMARTSTOR” software decides when to charge and discharge. Powervault describes this software as using weather forecasts, usage patterns and time-of-use tariff data to make that decision.
Powervault also has a long history of working with UK energy suppliers and grid operators on smart-tariff and flexibility trials. These include research-stage integration with Octopus Energy’s Agile tariff and a past agreement with OVO’s Kaluza platform. Some installations can also earn extra payments through Powervault’s own GridFLEX grid-support scheme. That said, these supplier partnerships and trial programmes have changed over the years. Confirm with Powervault or your installer which tariffs and schemes your specific system currently supports.
Strengths and limitations
As with any brand, Powervault’s own marketing understandably leads with its strengths. Here is a more balanced picture.
Strengths
- UK-designed and assembled, with a track record stretching back to 2012, longer than many newer entrants to the home battery market
- Modular Powervault P5 range (successor to the Powervault 3) covers 4 to 16 kWh usable, with the larger-capacity P4 extending the lineup up to 24 kWh usable for bigger installations, so smaller retrofits and larger whole-home setups can both be served by the Powervault product family
- Own-brand Portal and SMARTSTOR software for monitoring and automated charging, plus a history of smart-tariff and grid-flexibility trials with UK suppliers and network operators
- 10-year warranty with a published end-of-warranty state of health guarantee, rather than a vaguer lifetime claim
Worth checking before you buy
- Maximum output on the smallest current P5 model is just 2.3 kW, lower than some rival systems, so confirm it covers your home's peak demand before buying
- Uses first-life lithium-polymer (NMC) cells in the P5 rather than the LiFePO4 chemistry now used in Powervault's own newer P4 and PVCompact products, and increasingly standard among rivals, a difference some buyers may weigh when comparing safety and ageing characteristics
- Product names and specification sheets have changed more than once (Powervault 3, PVCompact, P4, P5), so check you are quoted against the current datasheet rather than an older one
- We have not independently tested Powervault's pricing, support or installation process ourselves
Where Powervault fits the market
Powervault sits in the mainstream, professionally installed home battery segment, aimed at homeowners retrofitting storage onto an existing or new solar PV system. This is different from the plug-in, DIY-friendly category covered by some other brands on this site. Powervault competes most directly with brands such as GivEnergy, Tesla Powerwall and Sunsynk. Its main differentiators are being UK-designed and assembled, and having a longer operating history than many newer entrants. It does not lead on raw capacity or price.
Unlike some of those rivals, Powervault’s own sales and installer network are concentrated in the UK. It is not marketed as widely across other countries. If you are still working out which capacity and format suit your home, however, our capacity guide and free calculator cover that ground independently of any one brand.
Common questions about Powervault
What capacity does a Powervault battery come in?
Powervault's current flagship, the P5 (successor to the Powervault 3), is sold in four sizes. It has a usable AC capacity of 4, 8, 12 or 16 kWh. Powervault's own brochure lists the underlying DC capacity as nominal 5, 10, 15 or 20 kWh, so the 20 kWh figure quoted for the largest model is its nominal rating, not what you can actually use. For larger installations, Powervault's separate P4 system extends usable capacity up to 24 kWh. The right size and model depend on your household's usage, rather than there being one standard figure.
Is Powervault a UK company?
Yes. Powervault incorporated in 2012, and its headquarters are in London. There, it also designs and assembles its home battery units rather than importing them as finished products.
Does Powervault work with Octopus Energy or other smart tariffs?
Powervault has a history of trialling smart-tariff and grid-flexibility integrations with UK suppliers. These include research-stage work with Octopus Energy's Agile tariff and a past agreement with OVO's Kaluza platform, alongside its own GridFLEX grid-support scheme. That said, these partnerships and schemes have changed over time, so confirm current compatibility with Powervault or your installer before buying on that basis.
What warranty does Powervault offer?
Powervault's current published specification sheet for the P5 gives a 10-year warranty with unlimited cycles. It also guarantees that the battery will retain at least 70% of its original capacity at the end of that period.
What battery chemistry does Powervault use?
Powervault's P5 (the direct successor to the Powervault 3) uses first-life lithium-polymer cells: a polymer pouch format built around NMC (lithium nickel manganese cobalt oxide) chemistry. This is different from the lithium iron phosphate (LFP) chemistry now common among many newer home battery brands. Powervault has itself already moved to LFP cells for its other current products, the P4 and PVCompact, so the P5 is now the one model in its own range still using the older NMC cells. That said, its warranty and cycle-life figures remain broadly comparable regardless.
How much does a Powervault battery cost?
Published UK pricing for the Powervault P5 and its predecessor, the Powervault 3, has ranged from around £4,700 for the smallest model to around £14,000 for the largest, excluding installation. That said, prices change over time and vary by installer. Check with an installer for a current quote, then use our calculator to work out the capacity you actually need before comparing costs.
Not sure what capacity suits your home?
Run your own numbers with our free, independent calculator and see the capacity and payback range that fits your usage.