Do solar panels and home batteries work in a power cut?
Solar panels without a battery
Most solar systems are linked to the grid. When the grid goes down, the system must switch off. This is a safety feature. It stops power flowing back into lines that workers think are dead.
So even on a sunny day, your solar panels will not power your home in a power cut.
Solar with a battery
A battery helps only if the system has backup and was set up for it. Many batteries are installed only to save money on bills. They do not keep the house on when the grid fails.
Not sure about yours? Ask your installer these two questions:
- Will my battery keep the house on in a power cut?
- Which circuits will it keep on, such as the fridge, lights and router?
Then ask how to test it safely. Test it once a year.
How long could a battery last?
As a rough rule, battery size divided by what you run. The table assumes a fridge, lights, a router and phone charging, with heating left out. It is a guide, not a promise.
| Battery size | In winter | In summer |
|---|---|---|
| Small, under 5 kWh | 5 to 18 hours | 7 to 30 hours |
| Medium, 5 to 10 kWh | 11 to 36 hours | 18 to 60 hours |
| Large, over 10 kWh | 23 to 54 hours | 36 to 90 hours |
Want a figure for your own battery? Make your own plan and tell it about your battery.
What to do now
- Find out if your battery has backup. Write the answer down.
- Keep torches, a battery radio and power banks, whatever solar you have.
- Do not rely on solar to run your heating. See does a heat pump work in a power cut.
See what your own home needs
Answer about 20 quick questions and get a plan for your household. Free, about 10 minutes, nothing stored.
Questions people ask
Do solar panels work in a power cut?
Not on their own. They switch off when the grid goes down, even in bright sun.
Does my home battery work in a power cut?
Only if it has a backup feature and was wired to do it. Ask your installer.
What is EPS?
EPS stands for emergency power supply. It is one name for a battery's backup feature. Different makers use different names, so ask your installer in plain words.
Can an electric car power my house?
Most cannot. Keep it above half charge so you can leave or charge a phone from it.
Related guides
Where this comes from
General guidance, not official advice. In an emergency, follow instructions from emergency services and gov.uk.