Sigenergy Gateway: what it does when the power goes off

When the grid goes down, a grid-connected solar system switches off with it, and a battery only keeps the power on where backup is part of the design. The Sigenergy Gateway, sold as the Sigen Energy Gateway, is the part that changes that for a SigenStor system. It sits between the grid and your home, detects the outage and keeps the circuits wired to it running on your battery and panels.

This guide covers what the gateway does, whole-home versus partial backup, the models and what your system needs first. Every product detail comes from Sigenergy’s own product pages, datasheets and installation guides, checked on 2 November 2026. We fit SigenStor, with the gateway where backup is included and suitable, for homes across Devon and Cornwall from our base near Okehampton, and you can read about our work as a Sigenergy installer.

What the Sigen Energy Gateway does

Sigenergy says the gateway, used with SigenStor, “instantly detects grid outages and transitions to backup power”, and that you can monitor and control the energy flow in the mySigen app. SigenStor is the system it works with: Sigenergy describes it as “5-in-One”, combining a solar inverter, an EV DC charger, battery power conversion, the battery pack and energy management.

The installation guide for the Sigen Gateway HomePro SP shows what wires into the gateway:

• The power grid, through a grid contactor.
• The inverter, which in a SigenStor is the Sigen Energy Controller.
• Backup household loads, the circuits that stay on in a power cut.
• Non-backup loads, the circuits that go off with the grid.
• A generator or smart loads, through a shared port.
• A bypass switch, which the guide says is normally turned off.

Why panels alone switch off in a power cut

This catches people out: panels on a sunny day won’t keep the lights on when the grid fails. A grid-connected system is designed to disconnect from the network when something goes wrong on it, and Sigenergy’s Energy Controller datasheet lists anti-islanding protection among its safety features. Our guide to what solar PV is covers the basics.

The gateway is what lets SigenStor carry on safely. It watches the grid connection and, when the grid fails, moves your backup circuits on to battery and solar power until the grid comes back.

What happens the moment the grid fails

Sigenergy’s headline figure is 0 ms load-side disruption, and it says the switch is designed so “you never notice a power outage”. The datasheets attach two conditions to that figure, and they matter more than the number:

There is some headroom for appliances that surge as they start. The Energy Controller datasheet gives a peak output of twice its nominal power for 10 seconds, with the caveat that “actual load starting performance depends on the load type”.

One more detail shows why this is installer work. In off-grid mode, the HomePro SP guide says, the gateway connects the system’s neutral to its functional earth through a relay “to create a grounding system”, so that if a fault occurs, “leakage protection and overcurrent protection devices are triggered”. Your RCDs and breakers keep protecting you on battery power, provided the wiring and earthing are right. Sigenergy’s guides say only trained or qualified people should work directly on the equipment, which houses the bypass switch.

Whole-home or partial backup

This choice shapes the whole design. The gateway has a backup port and a non-backup port, so each circuit from your consumer unit sits on one side or the other. There are three ways to use that:

• Partial backup. The circuits you’d miss most go on the backup port, such as the lighting, the fridge and freezer sockets and the router. Everything else goes off with the grid until power is restored. Fewer circuits make it easier to stay inside the Energy Controller’s rating, and the battery lasts longer.
• Whole-home backup. Every circuit stays on. The Sigen Energy Gateway HomePro SP-F is the single-phase model Sigenergy lists for this, with a 100 A grid port and a 100 A backup port, and Sigenergy says it “fully supports 100 amp single-phase backup power for the entire home”. The house can still only draw what the Energy Controller and battery can supply.
• Smart loads. The middle way on the HomePro models. The HomePro SP guide recommends wiring high-power equipment as smart loads, naming “heat pumps, pool heaters, clothes dryers, immersion heaters” among them, so they “can be cut off when the energy storage system has low power”. Lights, routers and other low-power equipment are wired as household loads.

Sigenergy’s own example of a smart-load rule is cutting power to a heat pump when the battery falls below 20%.

The gateway models Sigenergy lists

Sigenergy’s Home Energy Gateway page lists five home models, for single-phase and three-phase supplies.

Model	Supply	SigenStor units	Nominal AC power	Smart load power
Sigen Gateway Home	Single phase	1	12 kW	None listed
Sigen Gateway Home	Three phase	1	30 kW	None listed
Sigen Gateway HomePro	Single phase	1 or 2, 12 kW total at most	12 kW	12 kW
Sigen Gateway HomePro (SP-F)	Single phase	1 or 2	22 kW	12 kW
Sigen Gateway HomePro	Three phase	1	30 kW	30 kW

The HomePro datasheet rates the backup port at 54.6 A on the HomePro SP and 100 A on the SP-F, the model Sigenergy markets for whole-home backup. Sigenergy’s page is global rather than UK-specific, so we confirm at the survey which model is available and suitable.

Ask about backup for your home

What the gateway needs before backup works

If you already have solar panels from another maker, the equipment you have decides what fits, and our page on adding a battery to the panels you already have explains how we check.

How long the battery keeps you going

The gateway decides what stays on, and the battery decides for how long. Sigenergy’s battery datasheet gives these figures per module, with one to six modules on each Energy Controller:

Module	Usable energy	Maximum charge and discharge power
SigenStor BAT 6.0	5.84 kWh	3 kW
SigenStor BAT 10.0	8.76 kWh	4.6 kW

For a rough guide, divide the usable energy in kWh by the power you’re drawing in kW to get hours. One BAT 6.0 module carrying a steady 0.5 kW would last a little over 11 hours before any solar tops it up. Add a 2 kW appliance and it lasts under two and a half hours. In daylight, your panels keep supplying the house and charging the battery.

If a long outage ever drains the battery completely, the datasheet says it “must be recharged within 7 days after being fully discharged to keep battery healthy”. Our page on battery storage sized to your evenings explains how we choose capacity for everyday use.

Adding a generator as a second source

Sigenergy says the gateway supports connection to a diesel generator, including 2-wire start, and that you can control the generator remotely through the mySigen app. On the HomePro SP, the generator shares its port with smart loads. If you already have a generator, or a long outage would be a real problem, raise it at the survey.

The gateway’s own warranty

Sigenergy’s published inverter warranty for Europe lists the Sigen Gateway Home, HomePro and HomeMax models at 5 years. It adds that wear-prone parts, including circuit breakers, contactors and indicator lights, are covered for two years from the start date. That is Sigenergy’s cover for the equipment. Our 10-year workmanship warranty covers the installation work our own team does.

If a fault does appear, our repairs and fault-finding service works on systems we didn’t fit as well as our own. Every installation we do also includes a year of The Solar Owners Club, with an annual system health check and a dedicated support line.

Questions to settle at your survey

If backup matters to you, tell us early, because it shapes the design. It helps to think about:

You don’t need to open anything: we look at your electricity supply at the survey. Your system may need approval from National Grid before we can connect it, known as a G99 application, and we handle that for you. If anyone at home relies on powered medical equipment, talk to your network operator as well as to us, and our guide to power cuts in Devon and Cornwall covers who to call.

Is the Sigenergy Gateway right for your home?

Without a gateway, a SigenStor still does the everyday job of storing daytime solar for the evening. If losing power matters to you, because you work from home, keep a full freezer or just want the lights to stay on, the gateway is what turns that battery into backup.

The checks are the same for every home: a gateway to suit your supply and circuits, an Energy Controller rated above the backed-up loads, and enough battery for the hours you need. We design Sigenergy systems for homes across Cornwall and Devon, and if a Sigenergy Gateway suits yours, we’ll build it into the design and show you how it works in the app at handover.