What a battery actually does
A battery does not generate anything. It stores the electricity your panels produce during the day so you can use it in the evening instead of buying it back from the grid. Its whole value comes from turning exported electricity, paid at a low rate, into electricity you use yourself, which is worth much more.
A battery earns its keep on the gap between what you are paid to export and what you pay to import. The wider that gap, and the more you shift into your own use, the better it pays.
What decides whether it pays
Your usage pattern
A battery suits a home that generates a surplus during the day and uses most of its power in the evening, which is exactly the household for whom panels alone struggle. If you already use most of your generation as it is produced, a battery has less to capture and pays back more slowly.
Export rate against import rate
If your export payment is low and your import price is high, storing power to avoid buying it back is worth more. Some tariffs also let you charge the battery cheaply overnight and use it at peak times, which can matter as much as the solar itself.
Battery size
A battery that is too large rarely fills and never earns back its extra capacity, and one that is too small exports the surplus it was meant to catch. Sizing follows your daily surplus and your evening demand, not the biggest unit on the shelf.
Retrofit or fitted with the panels
A battery can be added to an existing solar system or fitted alongside new panels. Fitting it at the same time is usually tidier and cheaper on labour, but a well matched retrofit is perfectly normal if you already have solar.
When storage is worth it
- Your panels generate more during the day than you use
- Most of your demand is in the evening and overnight
- Your import price is high relative to what you are paid to export
- You want to use more of your own generation rather than sell it cheaply
When it is not
- You already use most of your generation as it is produced
- Your daily surplus is small
- The extra spend pushes the project past a payback you are comfortable with
Quoted both ways, every time
Because storage is the largest single swing in a solar quote, we price every job with and without it and show you the figures both ways rather than defaulting to the bigger sale. Whether the panels make sense in the first place is covered in are solar panels worth it, and the full cost picture in how much solar panels cost. Our solar service starts with a free no obligation survey.