When can you add a battery to existing solar?
You can add a battery to most existing solar PV systems. The key question is whether your current inverter is a hybrid model with battery-ready wiring. If it is, adding a battery is usually straightforward. If you have a standard string inverter, we replace it with a hybrid inverter that manages both solar generation and battery charging. A no-obligation survey checks your inverter, consumer unit, and available space.
What does a hybrid inverter upgrade involve?
A hybrid inverter replaces your existing string inverter and adds battery management, so one unit handles solar generation, battery charging, and discharge to your home. The upgrade is typically done alongside the battery install and may require a small wiring change at your consumer unit. Your written quote includes the inverter, battery, and all labour. Read more about inverter options on our inverter replacement page.
How does a battery change what I use from my solar?
Without a battery
Surplus daytime solar is exported to the grid. You buy grid electricity in the evening.
With a battery
Surplus solar charges the battery by day, then powers your home in the evening and overnight.
A battery increases self-consumption — the share of your solar you use yourself rather than export. This reduces the grid electricity you buy and pairs well with smart time-of-use tariffs.
Does the Smart Export Guarantee still work with a battery?
Yes. Adding a battery does not stop you earning from the Smart Export Guarantee (SEG). A battery simply lets you choose when to export and when to store, so you can maximise self-consumption and still export surplus electricity. Outgoing Octopus pays 12p/kWh flat (from 1 March 2026). Your DNO (SPEN or SSEN) notification is handled as part of the retrofit.
Is there 0% VAT on retrofit batteries?
Yes. 0% VAT on batteries applies until 31 March 2027, whether the battery is installed with a new solar system or retrofitted to an existing one. It is applied automatically at the point of sale — no application needed. After 31 March 2027 the rate is scheduled to return to 5%.
How much does it cost to add a battery?
A lithium home battery starts from £3,200, including installation and 0% VAT until 31 March 2027. If a hybrid inverter upgrade is needed, that is included in your written, itemised quote after the survey. Battery sizing depends on how much solar you generate and your evening usage. Interest-free credit up to £30,000 is available, subject to status. See our battery storage Scotland page for more detail.
How do I arrange a battery retrofit survey?
Call 0141 230 0198 or fill in the form above. We arrange a no-obligation survey of your existing solar system, inverter, consumer unit, and available space, then send a written, itemised quote. We respond within 2 hours during business hours and cover all of Scotland.