Sigenergy SigenStor in the UK: what you are buying

Sigenergy's SigenStor is a modular home battery system: an Energy Controller that works as the solar and battery inverter, with battery modules stacked on it. It is worth comparing if you want solar, storage and, optionally, electric-car charging managed from one system. Sigenergy has a UK sales team and a UK technical support line. Its European warranty (Sigenergy publishes no separate UK edition) gives 10 years on the controller and battery modules, with a warranty threshold of 60% of the battery's usable energy for 10 years or up to a set amount of throughput, whichever comes first. That threshold is a warranty condition, not a forecast of the capacity you will have. The value is in the details: how many kWh are usable, whether the quote includes a Gateway for power cuts, and how the warranty conditions fit the way you will use the battery.

If you are still deciding whether a battery is worth it at all, start with our guide to solar battery storage.

What SigenStor is made of

SigenStor is a system, not a single battery. Sigenergy describes it as "5-in-one": solar inverter, battery converter, battery, energy management and an optional DC car charger. In practice a quote is built from separate parts, and each one should be named:

Sigenergy's European warranty lists single-phase controllers from 3.0 to 12.0 kW. If your home has a single-phase supply, your quote will come from that range. The controller's kW rating matters for grid paperwork: on a single-phase supply, the G98 connect-and-notify route covers up to 3.68 kW of total inverter output. A controller rated or set above 3.68 kW, or one added alongside an existing solar inverter, means your installer applies to the network operator under G99 and gets approval before connecting. When we checked the ENA's type-test register (Connect Direct) on 23 September 2026, it listed SigenStor EC single-phase controllers from 3.3 to 12 kW: the 3.3 and 3.6 kW models under G98, the larger ones under G99.

Each battery module has its own DC-DC converter, which Sigenergy says lets modules connect in parallel and mix older and newer packs. Sigenergy's battery datasheet we checked (June 2026, BAT 6.0 and 10.0) allows 1 to 6 modules per controller. That helps if you add capacity later; ask your installer whether the space allows more modules.

Usable capacity: the number to compare

The module names are not their usable capacity. Sigenergy's European warranty gives the usable energy it guarantees for each module:

So a BAT 10.0 is 8.76 kWh usable, not 10 kWh. Compare quotes on usable kWh, and compare other brands on the same basis. The energy that reaches your appliances is lower again after conversion losses.

The throughput column matters for how you use the battery. A BAT 8.0 is covered for 27.30 MWh, which is about 3,500 full charges (27,300 kWh ÷ 7.8 kWh). Over 10 years that is roughly one full cycle a day (3,500 ÷ 3,652 days = 0.96). A battery that charges from solar by day and again from a cheap overnight rate can use that allowance faster than one cycle a day, and the capacity guarantee ends when the throughput limit is reached, even before 10 years.

Sizing: start with your evening use

A battery only saves money on energy you can put into it and use later. Start with what your home uses between the end of the solar day and the next morning, then look at how much your panels export on a typical day in each season.

Example (illustrative): if your home has about 2 kWh of solar surplus left after daytime use, a 7.8 kWh module does not store four times as much as a smaller one: there is only 2 kWh to store. Bigger capacity only earns its cost if you have the surplus to fill it, or a time-of-use tariff that lets you charge cheaply from the grid. Our guide to battery tariffs explains how those tariffs change the sums.

Power matters as well as capacity. The controller's kW rating, the number of modules and the backup design limit how many appliances the battery can run at once. An electric shower, an induction hob and a heat pump starting together can exceed the power available even when the battery has plenty of kWh left. Ask for a month-by-month estimate that shows energy stored, energy used from the battery, losses and the export you give up.

Backup and the Sigen Gateway

In a SigenStor system, backup is the Sigen Gateway's job: Sigenergy says it detects the outage, separates your home from the grid and runs the chosen circuits from the battery and panels. Sigenergy says its Gateway HomePro SP-F supports whole-home backup on a 100 A single-phase supply. Its headline "0 ms" changeover is a laboratory result for a three-phase model, the HomePro TP, and other Gateways may differ.

A Gateway is not on every SigenStor quote. Ask:

• which Gateway model is included, if any;
• which circuits stay on in a power cut, and which heavy loads are excluded;
• what backup reserve is set, and how much daily capacity that leaves;
• to see the changeover tested at handover.

Note that the Gateway has a shorter warranty than the rest of the system: 5 years in Sigenergy's European inverter-system warranty, with wear parts such as breakers and contactors covered for 2 years.

Charging your car from SigenStor

The optional DC charger module charges a car directly from the solar panels and battery. Sigenergy says vehicle-to-home and vehicle-to-grid (V2X) depend on the car and on standards not yet published, so don't count on either unless the installer shows written support for your car.

The warranty in detail

Sigenergy publishes a European edition of its SigenStor warranty (dated 27 May 2025) and no separate UK edition. Ask your installer to confirm in writing that this is the edition for your system. It says:

• 10 years for the controller and battery modules, starting when the system is activated on site (or 180 days after it leaves the factory if it has not been activated by then).
• a warranty threshold of 60% of usable energy for 10 years, or the throughput in the table above, whichever comes first.
• The system must stay online for firmware updates. After more than 90 days offline it goes into a "Safe Operation Mode"; after more than a year offline in total, the warranty drops to 5 years from activation.
• Report a fault within 30 days of it happening, through the mySigen app or your installer.
• If a repair is covered, the warranty pays for parts, labour for the on-site repair and shipping. It does not cover the technician's travel and accommodation unless Sigenergy agrees in advance.
• The warranty passes to the next owner only if the system stays where it was installed.

An optional extended warranty adds 5 years, to a maximum of 15, if bought within 12 months of activation. It keeps the 60% threshold with higher throughput limits.

UK support and checking a quote

Sigenergy lists UK contacts on its website: a technical support line (+44 20 3872 0618) and a UK service email (service.uk@sigenergy.com). In practice, Sigenergy's warranty treats its distributors and installers as the first service channel, so your installer is the first call.

There is no single installed price for "a Sigenergy battery": the controller, number of modules, Gateway, EV module and electrical work all change the total. Our solar battery cost guide covers typical UK prices. A quote you can compare should list:

• the controller model and kW rating, and each BAT module by name;
• total usable kWh;
• the Gateway model and backup circuits, or a clear statement that there is no backup;
• the G98 notification or G99 application;
• where the stack goes, with floor space for any extra modules, and whether that spot meets PAS 63100:2024, the BSI fire-safety specification for home batteries;
• the warranty edition, and whether an extended warranty is included.

An installed battery is zero-rated for VAT until 31 March 2027, then 5% from 1 April 2027 unless the relief is extended, when the installer supplies and fits it in your home, including when you add it to existing panels. MCS's product directory does not list batteries, so check the installer's MCS certificate number instead. MCS certification no longer comes with consumer-code membership, so if deposit protection matters to you, look the installer up on the RECC or HIES register as well. If the system is faulty or badly fitted, your rights under the Consumer Rights Act 2015 are against the installer who sold it, alongside Sigenergy's warranty. Our guide to comparing solar quotes covers the rest of the checklist, and choosing an installer covers checking the company itself.

Our view: SigenStor is a strong fit when its integration saves you separate boxes, the quote shows usable kWh and backup clearly, and the installer can service it. Be more cautious if the extra cost rests on backup or car-charging features that your home or car can't use.

Sigenergy FAQs

How much of a BAT 8.0 can I use?

7.8 kWh, according to Sigenergy's European warranty. The energy that reaches your appliances is a little lower after conversion losses.

Does SigenStor work in a power cut?

Sigenergy's backup design uses a Sigen Gateway, installed and wired for backup, and it needs charge in the battery. If your quote has no Gateway, ask the installer in writing whether anything will stay on in a power cut.

What happens to the warranty if my internet goes down?

Sigenergy's warranty asks you to keep the system online, and offline time adds up. After 90 days offline the system enters a Safe Operation Mode, and after more than a year offline in total, the warranty falls to 5 years from activation.

Is there a UK warranty for Sigenergy?

Sigenergy publishes a European edition and lists UK support contacts. Ask your installer to confirm in writing which warranty edition applies to your system.