Ever wondered do solar batteries work in a blackout?
Short answer: Yes—but not always.
If your solar setup isn’t designed for blackouts, your home could still go dark even with a battery and panels on the roof.
That’s why thousands of Aussie homeowners are upgrading their systems to stay powered when the grid goes down.
This guide explains exactly how solar batteries can keep the lights on, what you need to make them work in a blackout, and why it’s a game-changer in blackout-prone areas of Australia.
Do Solar Batteries Work in a Blackout?
Yes, solar batteries can work in a blackout. But whether they actually will depends on how your system’s set up.
If your solar panels are just hooked into the grid, they’ll switch off as soon as the power goes out. That surprises a lot of people. You’ve got panels on the roof and the sun is shining — so why’s everything still off?
It comes down to how most systems in Australia are installed. A standard grid-connected solar system shuts down during a blackout to protect utility workers. It’s a safety rule, not a flaw.
If electricity from your solar panels were still flowing into the grid, it could hurt someone trying to fix the power lines. That’s called anti-islanding protection, and it’s built into every grid-tied inverter.
But if you’ve got a solar battery with blackout protection, it’s a different story. These systems are designed to disconnect from the grid safely and continue powering your home. They use a special inverter and switch that isolates your house from the grid while still letting your solar panels charge the battery during the day.
There are a few main types of setups:
- Grid-tied with no battery – cheapest and most common. Shuts off during a blackout.
- Grid-tied with battery – only works in a blackout if there’s a backup gateway or hybrid inverter.
- Off-grid system – completely independent. Keeps running, but usually costs more and needs careful planning.
Australia has plenty of spots where blackouts are common, especially during bushfire season. In parts of Victoria, South Australia, and regional Queensland, it’s not unusual to lose power for hours — sometimes longer. Even here in Western Australia we get power losses in our semi rural and rural areas. Perth areas occasionally go down as well especially in the hills areas and outskirts of the city.
That’s when having a battery can make a big difference. It means the fridge keeps running, the lights stay on, and you’re not left in the dark waiting for the grid to come back online.
But again, the key is in the setup. Just installing a battery isn’t enough. If blackout protection wasn’t added during the install, you won’t have backup power when you need it most.
Why Most Grid-Tied Solar Systems Shut Down in a Blackout
When the power cuts out, most people are shocked to find that their solar system shuts off too. They think, “I’ve got panels on my roof — why can’t I use them?”
The answer’s got to do with how grid-tied systems are wired. These setups are directly connected to the main power grid. So when the grid goes down, your system goes down with it. That’s actually built in on purpose.
There’s a rule baked into every standard inverter called anti-islanding protection. It’s a safety feature. If your panels were still feeding power back into the grid during an outage, it could seriously hurt someone — like a lineworker fixing the wires outside. So the inverter automatically shuts everything down the moment it detects the grid is offline.
This happens fast. Within milliseconds of the outage, your panels stop sending power anywhere. Your lights flicker off, and just like everyone else, you’re left waiting for the grid to come back.
Here’s the thing though — it’s not because solar panels can’t generate electricity during a blackout. They definitely can. It’s just that standard systems aren’t allowed to operate without the grid unless they’re set up to handle it safely.
Some homeowners find this frustrating. They invested in solar, they’re producing clean energy every day, but still can’t use it in an emergency.
A typical grid-tied setup looks like this:
- Solar panels generate electricity during the day
- Inverter converts the DC power into AC for your home
- Any unused power goes to the grid, and you earn feed-in credits
- If the grid fails, your whole system shuts off to prevent any energy from leaking into the network
So even though your panels are technically working when the sun’s out, the inverter blocks everything for safety. Unless you’ve got the right gear — like a battery with blackout protection — your home stays in the dark.
When Solar Batteries Can Power Your Home in a Blackout
If your solar battery system is properly set up, then yes — it can power your home during a blackout. But it’s not automatic with every system. It all comes down to the parts installed and how they’ve been configured.
You need more than just a battery. What actually makes the system work in an outage is a backup gateway or a hybrid inverter.
These devices allow your battery to disconnect from the grid and safely power your home without sending electricity out to the network. Without that gateway, your battery just sits there during a blackout doing nothing.
There are a few things that need to be in place for it to work:
- A hybrid inverter or battery inverter that supports blackout protection
- A backup switch or gateway to isolate your home from the grid
- Battery storage with enough capacity to run your essentials
- Emergency circuits set up by your installer (these power your critical appliances during a blackout)
Most installers in Australia will ask which appliances you want running during an outage. This helps them design the system to suit your needs. In a typical Aussie home, people usually want to keep a few key things going:
- Fridge – so food doesn’t go off
- Wi-Fi router – to stay online and get updates
- LED lights – for safety and comfort
- Phone chargers and laptops – so you’re not stuck with flat batteries
- Medical devices – for anyone relying on CPAP machines or home oxygen
You probably won’t run the air con or electric oven during a blackout unless you’ve got a very large battery. Most setups focus on keeping the basics running comfortably for a few hours or even overnight, depending on your usage.
Once the sun comes up, your panels can recharge the battery again — as long as your system has been designed to operate off-grid temporarily.
That’s why it’s so important to check whether blackout protection was actually included during installation. A lot of systems in Australia don’t come with it by default.
What You Need to Make Solar Batteries Work in a Blackout
If you want your solar battery to keep things running during a power outage, your system needs to be built for it. Just having a battery isn’t enough. There are specific parts that make all the difference, and if one’s missing, your home will still go dark when the grid goes down.
1. Backup Switch or Backup Gateway
This is what allows your home to disconnect from the grid safely. Without it, your battery can’t legally or safely power your house during a blackout. It’s one of the most overlooked parts, but also one of the most important. Systems like the Tesla Powerwall include a backup gateway. Others may require it as an extra.
2. Hybrid Inverter
Your inverter is like the brain of the setup. A hybrid inverter controls how energy flows between the grid, your solar panels, your battery, and your home. If it’s not designed to handle blackout mode, then the battery won’t work when the power cuts out.
3. Automatic Transfer Switch (ATS)
Some setups include an ATS to automatically switch your home to battery power during an outage. This all happens in seconds, and you might not even notice the switch. Without it, you’d need to manually switch things over — not ideal in the middle of the night or during a storm.
4. Enough Battery Capacity
Battery size matters. If you’ve got a 5kWh battery and your household pulls 3kW per hour, that battery won’t last long. For blackout protection, most Australian households aim for 10kWh or more, depending on how much they want to power.
5. Emergency Circuits Set by Your Installer
These are the specific circuits that stay powered during an outage. Your installer will wire them in during setup. The most common ones are:
- Fridge
- Modem/Wi-Fi
- A few lights
- Powerpoints for phones and laptops
- Medical devices if needed
Your entire house won’t stay on unless you’ve got a massive system. Most people just back up the essentials to stretch battery life and avoid wasting energy on things like air con or the oven.
When everything is installed and set up correctly, your solar battery can give you real peace of mind during blackouts.
But every part needs to work together — if one thing’s missing, the whole backup system can fail. Always double check what’s included before signing off on your solar install.
How Long Solar Batteries Last in a Blackout
How long your solar battery lasts during a blackout depends on how much energy you use and how big your battery is. It also comes down to what you’re running.
A fridge and a few lights? That’s easy. Air con and a clothes dryer? That’ll drain your battery way faster.
Let’s say you’ve got a 13.5kWh battery, like a Tesla Powerwall. That’s a decent size for backup power. If you’re careful and just running the essentials, it can last about a full day.
Here’s a common example that works well in most Aussie homes:
- Fridge – around 200 watts
- Wi-Fi router – about 50 watts
- A few LED lights – roughly 100 watts total
- Phone chargers and laptops – another 100–150 watts tops
At that rate (about 0.5kW total), you’re using energy slowly, and the battery could keep things going for 24 to 27 hours.
But if you start adding high-powered stuff like:
- Washing machine
- Dishwasher
- TVs
- Fans or small heaters
…you’ll see a much shorter runtime — maybe just 6 to 12 hours, depending on how long those appliances run.
Here’s a basic breakdown:
| Battery Size (kWh) | Essential Use (0.5kW) | Moderate Use (1kW) | High Use (3kW) |
| 7.2 | ~14 hours | ~7 hours | ~2.4 hours |
| 10 | ~20 hours | ~10 hours | ~3.3 hours |
| 13.5 | ~27 hours | ~13.5 hours | ~4.5 hours |
| 24 | ~48 hours | ~24 hours | ~8 hours |
If you live in an area with frequent outages or extreme weather, having a larger battery or managing your loads carefully makes a big difference.
Keep usage low, and your battery will stretch longer — just enough to get you through until the grid’s back or the sun comes up to recharge your system.
Key Takeaway
If you’re thinking about using a solar battery during blackouts, the setup matters more than anything.
A battery by itself won’t do much unless it’s paired with the right gear — things like a hybrid inverter, backup gateway, and emergency circuits. Once those are in place, the system can actually power your essentials when the grid goes down.
This is especially handy if you’re living in a rural spot, or somewhere that gets hit with blackouts during storms or fire season. Being able to keep the lights on, the fridge cold, and the Wi-Fi running makes life way less stressful.
At Off Grid WA, we help people across Western Australia get systems that actually work when the power cuts out.
We’ve seen too many installs that look good on paper but don’t hold up when it matters most. If you want help building something reliable — whether you’re starting fresh or upgrading — check us out.
FAQs About Solar Batteries in Blackouts
Can solar panels work in a blackout without a battery?
No – unless you’re off-grid or have a hybrid system with battery and backup.
How much battery capacity do I need for blackout protection?
Enough to run your fridge, lights, Wi-Fi and essential appliances – usually 10kWh+.
What happens if the battery runs out during a blackout?
You lose power just like a normal outage. Unless you have solar and the sun is up.
Can I add a battery to my existing solar system for blackout use?
Yes, but you might need a hybrid inverter and backup gateway installed.
Are solar batteries better than generators for outages?
They’re quieter, cleaner, and automatic – but more expensive upfront.
