Adding a battery to solar panels you already have
Where a house already has panels, a battery holds on to the midday surplus so it runs the house after dark rather than going out to the grid. There are two ways to do it, and the right one depends mainly on the inverter you already have.
An AC-coupled battery. The battery comes with its own inverter and connects into your home's wiring separately from the existing solar inverter, which carries on exactly as before. This is usually the simplest retrofit and the least disruptive.
A hybrid inverter. The old solar inverter comes out and one hybrid unit runs the panels and the battery together. It makes most sense when the existing inverter is failing or near the end of its life, because you would be paying to replace it anyway.
If your panels earn Feed-in Tariff payments, take care before anything is connected. Tell your FIT licensee, the supplier that pays you, and send them a diagram of where the battery will sit. The generation meter must go on recording only what the panels produce, never electricity that has come from the grid by way of the battery. An AC-coupled battery fitted after the generation meter is the easiest way to keep that straightforward. A hybrid arrangement can still work, but it needs different metering, and the position of the battery can affect whether you keep your deemed export payments.
A battery without solar panels
A battery does not need panels at all. Charged from the grid in the cheap overnight hours, it runs the house through the expensive part of the evening. It suits homes where the roof is shaded, faces north or cannot take panels, and households already on a time-of-use tariff for an electric car or a heat pump.
You need a smart meter and a tariff with a genuine gap between the cheap and expensive rates, because that gap is where the whole value lies. Tariffs change, so it is worth being sceptical of any sales figure that assumes today's rates for the whole life of the battery. Our guide to what solar and batteries actually pay back in South Yorkshire works through the numbers honestly.
Where a home battery can and cannot go
This is the part of a solar battery installation that is easiest to get wrong, so it is the first thing we survey. PAS 63100:2024, the British Standards Institution's fire safety specification for home batteries, rules out a list of places:
bedrooms, and cupboards or spaces that open into them;
hallways, landings, stairs and any other way out of the house in a fire;
lofts, roof spaces and voids;
cellars and basements with no access to the outside;
anywhere within 2 metres of stored fuel or flammable materials, and outdoors within a metre of doors, windows, vents or escape routes.
In practice, that often leaves a garage, an outbuilding or an outside wall. An attached garage needs fire separation from the house, and a battery where a car parks needs protecting against knocks. In a terrace with no garage and a small back yard, the spot takes real thought, and occasionally the honest answer is that there is no good one.
A battery on an outside wall has to be rated for outdoor use. Lithium batteries also dislike the cold: many will not charge below freezing unless they have built-in heating, so a unit in an unheated garage or on a north wall can do less in January than the brochure suggests. We factor that into where it goes and which model we recommend.
Amendment 4 of the wiring regulations, published in April 2026, applies to all new work from 15 October 2026 and gives battery storage its own chapter for the first time.
Will it keep the lights on in a power cut?
Not by default, which surprises many people. A battery connected to the grid is designed to shut down when the grid fails, so it cannot push power back into cables that engineers may be working on.
Backup has to be designed in. It needs a changeover switch that disconnects the backed-up circuits from the network on every live conductor, neutral included, before the battery takes over. It also needs an earth electrode of its own, because most homes rely on the network's earth, and that cannot be relied on once the house is running as an island. Most backup set-ups feed a chosen group of circuits, such as the fridge, freezer, lights and boiler, though some cover the whole house. Decide whether you want it before the equipment is chosen, because adding it afterwards can mean different hardware.
The paperwork behind a solar battery installation
Northern Powergrid looks at the panels and battery together. If the combined rating of the solar and battery inverters stays within 16 amps per phase (roughly 3.68kW on a single-phase supply), we notify them within 28 days of connection. Above that, the installation needs their approval before it is switched on. This is where retrofits get caught out: a typical older solar system and a new battery can each sit under the limit on their own and still go over it together. Many of them qualify for a quicker fast-track application if the export to the grid is capped. We make the application, so you do not have to learn the forms.
A battery also means new circuit work, which is notified to building control, and you receive a compliance certificate alongside our own installation paperwork. Until 31 March 2027, a battery supplied and fitted in a home by an installer is zero-rated for VAT, whether it goes in with panels or on its own; buying one to fit yourself does not qualify. After that, the rate is due to rise to 5%.
Home battery storage across South Yorkshire
We design, fit and commission batteries from our base in Wath upon Dearne, working across Rotherham, Barnsley, Sheffield and the surrounding towns. If you have not fitted panels yet, our solar PV and battery service covers the whole system, and the solar savings estimator gives you a starting figure from your own usage. A battery can also sit alongside an EV charger fitted as part of the same visit.