Blackout Protection: Why Solar and Batteries Fail Without Backup

If you are reading this in the dark, here is something most people only discover in the middle of an outage: the solar panels on your roof are switched off too.

Not broken. Switched off, deliberately, by the inverter. And unless you have one specific piece of equipment, a home battery will not help you either.

This is the part of the sales conversation that tends to get skipped, so here it is in full, ahead of the storm season rather than during it.

Why your solar shuts down when the grid does

Every grid-connected solar inverter in Australia is required to disconnect the moment it detects the grid has gone down. It is called anti-islanding, and it exists to protect the linesmen working on the wires outside your house. If thousands of rooftop systems kept pushing power into a network that crews believe is dead, people would be killed.

So the rule is not a fault, and it is not something an installer can switch off for you. It is a safety standard, and it applies to every conventional solar system on every roof in the street.

The practical effect is the one nobody mentions at the quote stage: on a bright, sunny morning, with a perfectly good system on your roof, you will be sitting in the dark alongside neighbours who have no solar at all.

Why a battery on its own often isn’t the answer either

Adding a battery feels like it should solve this. Frequently, it does not.

A standard battery installation is designed to do one job well: store your excess solar during the day and use it in the evening, so you buy less power from the grid. That is a financial function, and it runs while the grid is up.

For that stored energy to run your house during an outage, the system needs to do something quite different. It has to physically disconnect your home from the grid, form its own stable little electrical island, and then power your circuits from the battery — all without back-feeding the street. That switching has to happen automatically, safely, and fast.

That is not a software setting. It is a separate piece of hardware, and if it is not in your quote, you do not have blackout protection. You have a battery that saves you money on your bill and goes quiet at exactly the moment you most wanted it.

What the Sigen Gateway actually does

The Sigen Gateway is the device that turns a Sigenergy SigenStor into a home backup system. It sits between your switchboard and the grid connection, and it is the part that does the disconnecting and reconnecting.

Sigen Energy Gateway installed on an exterior wall, providing whole-home backup power switching

A Sigen Energy Gateway installed on an exterior wall — the hardware that switches your home onto battery power in under five milliseconds.

What that gives you:

Switchover in under five milliseconds. Fast enough that a desktop computer does not reboot, the internet stays up, and the lights do not even flicker. In practice the first you know about the outage is a phone notification, or your neighbours’ houses going dark.
Whole-home or selected-circuit backup. Sigenergy inverters are generally sized generously enough to back up the whole house through most outages, which is why whole-home backup is our default recommendation. Some homes are better served by nominating specific circuits instead — it depends on your switchboard, your loads and what you want covered. Our consultants will talk you through what makes the most sense for your place.
Your solar keeps working. This is the part people underestimate. Once the Gateway has islanded your home, the panels on your roof are allowed to run again, because there is no longer any risk of feeding the street. Your battery recharges from the sun during the day.
Generator input. If you already have a generator, the Gateway supports two-wire start, so it can bring the generator in automatically for a long outage.

That third point is the one that changes the maths on a multi-day outage. A battery on its own is a fixed amount of energy — when it is gone, it is gone. A battery plus solar plus a Gateway recharges every morning. That is the difference between getting through one evening and getting through the best part of a week.

The honest version of what you can run

Backup power is not the same as nothing having happened. Anyone who tells you otherwise is selling.

A typical home battery holds somewhere between 10 and 20 kilowatt-hours of usable energy. Your fridge, lights, internet, phones and a few power points will draw a modest amount of that and will run for days, especially with solar topping the battery up each morning. Ducted air conditioning, an electric oven, a pool pump and an instantaneous hot water system will not — run all of those and you will empty a battery in hours.

This is exactly why the right setup is a conversation rather than a rule of thumb. A properly sized Sigenergy battery will usually run the whole house through the loads that matter, but if you have something genuinely heavy on the circuit — a pool pump, ducted air conditioning, an instantaneous hot water system — our consultants will factor that in and recommend whole-home or selected-circuit backup accordingly.

A well-designed backup setup is one where the outage becomes an inconvenience rather than an event: the food in the fridge survives, everyone’s phones charge, the kids’ devices work, you can see, and you can find out what is going on.

Investment and Cost Considerations for Backup Systems

The Gateway is an addition to a battery system rather than a standalone product. As a guide, it adds roughly $2,000 to $3,000 to an installed Sigenergy system, on top of the battery and inverter. Federal incentives come off the installed figure — our Queensland rebates guide sets out what applies.

It is far cheaper to include backup capability in the original design than to retrofit it later. Adding a Gateway to an existing installation means switchboard work and another round of paperwork that you would have avoided by deciding up front.

Why the timing matters right now

South East Queensland’s storm season runs from roughly October through to March, and the damaging events cluster in the middle of it.

The recent record is not subtle. Ex-Tropical Cyclone Alfred took power from more than 200,000 South East Queensland homes in March last year, and it was the best part of a week before Energex had 90% of customers restored. One night of severe storms last November left close to 100,000 customers still off supply the following morning. These are not freak events any more; they are the season.

The problem with deciding during an outage is that everybody decides during an outage. Battery installations need a connection approval from Energex before they can be energised, the equipment has to be in stock, and installers’ calendars fill up immediately after the first serious storm. A system you commit to in September is protecting you in December. A system you enquire about in December is protecting you next winter.

That is the whole argument for doing this now, in a quiet week, rather than by candlelight.

What to do next

If you already have solar and are wondering whether you are covered, check your paperwork for a Gateway or backup device. If there isn’t one, you do not have blackout protection, whatever your battery is capable of on paper.

If you are considering a battery, make backup an explicit part of the brief rather than an afterthought. Ask which circuits would be on the backup supply, what happens to your solar during an outage, and what size Gateway your setup needs.

We are a Brisbane installer and we have put these systems into houses across South East Queensland, including through the last two storm seasons. If you want to know what backup would look like for your house — which circuits, what size, what it would cost — ask us and we will set it out properly.