Do solar panels work in a power cut?
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Solar panels let you make your own electricity from daylight, so you buy less from the grid and spend less on your bills. Add a battery and you can use more of that electricity in the evening too. With the right setup, a battery can even keep the essentials running when the grid goes down.
That last part comes with a catch, and it surprises a lot of people. On their own, solar panels switch off in a power cut.
It’s a fair thing to be asking about right now. Two named storms hit in a week in October. Storm Austen arrived on 23 October with gusts of up to 100 mph and left thousands without power. Storm Boelo followed over the weekend of 24 to 25 October, and reports put around 90,000 homes without power. Last January, Storm Goretti left nearly 1.2 million without power.
Power cuts are still rare, and the average home loses power for under an hour a year. But they do happen, so it’s worth knowing what your system would do. Here’s why panels switch off, and what keeps your home running.
The short answer
Standard solar panels switch off when the grid goes down. A solar battery with backup can keep your home powered, but not every battery does this.
Why solar panels switch off in a power cut
Home solar is designed to work alongside the grid, not without it. When the grid goes down, your inverter shuts off automatically. That’s a safety feature, not a fault. It stops your system sending electricity back onto lines that engineers may be working on. So on a sunny day with a power cut, you can have panels on your roof and still have no power inside.
What keeps your home running
A battery with backup. It needs a switch that disconnects your home from the grid when the power goes, so your panels and battery can run the house on their own. Many standard batteries don’t have this and shut down too. If backup matters to you, it’s much easier to plan for it before installation than to add it later and we can help you.
What a battery with backup can and can’t do
It can keep essentials running: lights, the fridge, the router, phone chargers. How much else it handles depends on the size of the battery and how much power your home draws at once. It can’t run everything forever. Your panels recharge it in daylight, but in a winter evening cut you’re relying on what’s stored.
Is a battery with backup worth it?
Backup is a bonus rather than the main reason to get a battery. A battery is also there every day, helping you use more of your own solar and buy less from the grid.
A battery with backup is likely to be worth it if:
- power cuts are a regular thing where you live
- you work from home or rely on medical or other essential equipment
- you want peace of mind as well as lower bills
- you’re already planning to add a battery to your solar
It may be less worthwhile if:
- power cuts are rare where you live and you’re not too worried
- you’re mainly after bill savings, as a standard battery may do that for less
- the extra cost of backup makes the payback too long for your plans
The honest answer is that it depends on your home and how much a power cut would affect you.
Questions to ask your installer
- does this battery work in a power cut, or only when the grid is on
- will it power the whole home or just selected circuits
- how many kWh does it store, and how long will that last with the way we use power
- can it run the oven, heat pump or EV charger, or only lighter loads
- does it switch over automatically
- can backup be added later
Solar and backup at a glance
| Question | Short answer |
|---|---|
| Do solar panels work in a power cut? | Not on their own. They switch off for safety |
| Can a battery keep my home powered? | Yes, if it has backup |
| Do all batteries have backup? | No. Many shut down with the grid |
| Will it run everything? | Not necessarily. It depends on battery size and what you’re running |
| Is a battery worth it without backup? | Often yes, for the bill savings |
Frequently asked questions
Will my solar panels power my home in a power cut?Not on their own. Standard systems switch off automatically when the grid goes down. You’d need a battery with backup.
Is it safe to use solar in a power cut?Yes, with the right equipment. A backup system disconnects your home from the grid, so nothing is sent back onto the lines.
Can I add backup to a battery I already have?Sometimes. It depends on the battery. Check with your installer before you assume.
Does a battery work in a power cut in the dark?Yes, for as long as it has charge. It won’t recharge until the sun comes back or the grid returns.
Get a straight answer for your home
Every home is different. If you want to know what a solar and battery system, with or without backup, would do for yours, get a free estimate from OVO Solar & Heating and we’ll take a look and give you a straight answer.