Most of what you will read about the Sigenergy SigenStor online is either a spec sheet or a sales page. This is the installer’s view: what the system is, the numbers that actually matter when it goes on your wall, and the honest answer to who it suits. Every figure here is taken from the published datasheets and distributor specifications linked at the end, because Sigenergy’s own website blocks automated reading and we would rather cite something you can check.
What SigenStor actually is
SigenStor is a single unit that does five jobs: it is the solar inverter, the battery, an optional DC charger for an electric car, the energy management system and the backup supply for a power cut. Everything is controlled from one app, mySigen. That matters more than it sounds. A typical “solar plus battery” install from five years ago was three boxes from two or three manufacturers, each with its own app, its own warranty and its own idea of what should happen at 5 pm. SigenStor collapses that into one enclosure and one conversation if anything ever needs attention.
The second thing that defines it is the stack. The battery is not a fixed size; it is built from modules that physically clip together, five layers high at most, and the inverter sits on top.
The battery: 5 kWh and 8 kWh modules
Battery modules come in two sizes, 5 kWh and 8 kWh, and a stack takes between one and six of them. That gives a ceiling of 30 kWh with the smaller module or 48 kWh with the larger one in a single stack, and up to ten stacks can run in parallel, which is far beyond anything a house needs and is really there for commercial use. The cells are 280 Ah, in what the datasheet describes as a five-layer stackable design.
For a home, the useful part is the granularity. A three-bedroom semi with ordinary evening use is usually right on two 5 kWh modules. A larger house with an EV or a heat pump is more often two or three 8 kWh modules. If a second car arrives in two years, you add a module; nothing already on the wall is wasted. That is the single biggest practical difference between SigenStor and a fixed-capacity battery, and it is the reason we end up recommending it for most new solar-and-battery installs.
The inverter and your grid connection
The hybrid inverter runs from 3 kW to 12 kW on single-phase supplies and 5 kW to 30 kW on three-phase. Almost every house in our area is single-phase, and the sizes we fit most are 5 kW and 6 kW.
That size decision has a paperwork consequence. Under the Energy Networks Association’s engineering recommendations, a generator up to 16 A per phase, which is 3.68 kW, is a G98 connection and is simply notified to the network operator after installation. Anything larger is a G99 application that has to be approved before the work starts. A 5 or 6 kW SigenStor inverter is therefore a G99, and the approval is the slowest part of the whole project, measured in weeks rather than days. We submit it the moment the design is agreed so the install date is not waiting on it.
Across our patch the operator is National Grid Electricity Distribution, but which licence area you are in depends on the postcode: Birmingham, the Black Country and Worcester sit on the West Midlands network, while Coventry, Tamworth and Burton come under East Midlands. We check it from your postcode rather than assume, because the application goes to a different team.
Backup, the EV module and the app
Backup is built in, with a 0 ms switchover, so when the grid drops the house does not notice. How long it lasts depends on how much energy is in the stack and what is running; a fridge, lights, router and a few sockets will run for a long time on 10 kWh, an electric shower will not. During commissioning we agree which circuits are on the backup side, and that is a design conversation worth having at survey rather than on the day.
The optional EV module charges a car directly on DC from the battery and the panels rather than through a separate AC wallbox on the wall. For some households that is the neatest answer; for others a conventional 7 kW smart charger that charges from solar surplus is simpler and cheaper, and we will tell you which suits the car you actually drive. There is more on that choice on our home EV charger installation page.
The mySigen app is where you see generation, consumption, what the battery is doing and, importantly, where tariff schedules live. If you move to a time-of-use tariff later, the battery can be told to charge cheaply overnight and that is a settings change, not an engineer visit.
Warranty and build
The product warranty is 10 years and the enclosure is rated IP66, which is a higher ingress rating than most home batteries and means an external wall is a realistic location if there is no space in a garage or utility room. The detailed warranty terms, including capacity retention, are on the datasheet, and we attach the exact document for the model we quote rather than summarising it here.
Whatever the enclosure rating, the installation itself has to meet the domestic battery safety specification. BS 7671, the UK wiring regulations, added a new Chapter 57 for battery installations in its 2026 amendment and requires batteries in dwellings to be installed to PAS 63100, the BSI fire-safety specification that governs where a battery can go, what it can be mounted on and how it is separated from escape routes. Every battery we fit is installed to it by NICEIC-registered engineers.
Who it suits, and who it does not
SigenStor suits a house that is having solar and a battery together, or that already has a decent-sized array and wants backup and growth. It suits households with an EV or a heat pump on the horizon, because the module count can follow the load. It suits anyone who wants one app and one company to call.
It is the wrong answer for a small roof with modest evening use, where a single 5 kWh unit from another brand will cost less and do the job. It is also not the cheapest way to add storage to an existing system if your inverter is new and you only want a few kilowatt-hours. We fit Duracell Energy batteries for exactly those cases, and the survey decides, not the brochure. Our home battery storage page sets out how we size a battery and when it pays.
What it costs, the honest version
Sigenergy does not publish a UK list price, and we will not invent one. The system is priced on the module count and inverter size your house needs, and it comes back to you as a fixed figure on a written quote with the datasheet attached.
Two things frame the value. First, installing a battery in a home is 0% VAT until 31 March 2027, after which the rate returns to 5%. Second, the arithmetic of self-consumption: under the Ofgem price cap for October to December 2026, electricity is 26.32p per kWh, and the most common export tariff, Octopus Outgoing Fixed, pays 12p per kWh. Every unit the battery keeps at home instead of exporting is worth the difference, 14.32p. A house that shifts 8 kWh a day from export to evening use saves roughly £418 a year on that gap alone, before any time-of-use charging. That is illustrative arithmetic from published rates, not a forecast for your house; the survey models it from your smart-meter data.
How we install it
Green Tech Hub supplies, installs and commissions Sigenergy SigenStor systems. We are MCS-certified for both solar PV and battery storage through NICEIC (NIC-600049), which is the certification your export tariff and your insurer ask for. The process is survey and modelling, a fixed-price design, the G99 application, a one-day install to PAS 63100, then commissioning with you: backup circuits, tariff settings and the app. After that, the engineer who installed it is the one you call. Full detail is on our Sigenergy installer page, and the areas we cover are on the Black Country, Worcestershire and Staffordshire pages.
Sources
- SigenStor battery sizes, stack limits, IP66 rating, 10-year warranty and five-in-one description: Senergy Direct, Sigenergy SigenStor battery
- 280 Ah cells, five-layer stackable design, 0 ms backup switchover: SigenStor Home datasheet (PDF)
- Inverter sizes, 3 to 12 kW single-phase and 5 to 30 kW three-phase: Wired by Jessops, SigenStor specifications
- G98 and G99 thresholds: Energy Networks Association, engineering documents
- PAS 63100 and BS 7671 Amendment 4 Chapter 57: IET Wiring Matters
- 0% VAT on home solar and battery installation to 31 March 2027: HMRC VAT Notice 708/6
- Ofgem price cap, 1 October to 31 December 2026: Ofgem energy price cap
- Octopus Outgoing export rates: Octopus Energy Outgoing