Solar battery storage

A home battery stores the solar power your panels make during the day so you can use it after dark, instead of exporting it to the grid and buying electricity back in the evening. It doesn't generate anything itself. It changes when you get to use the power you've already made.

Every Pro-Fit solar install comes with a battery-ready hybrid inverter, whether you add a battery on day one or later. Below is what a battery adds to our published prices, how it works with an existing system, an EV or a time-of-use tariff, and what backup for key circuits actually means.

What a home battery does

Panels generate most strongly through the middle of the day. Most households use relatively little power then and far more in the morning and evening. Without a battery, the surplus goes to the grid for an export payment. With one, it's stored in your own house and drawn down once the sun's gone in.

A battery doesn't make your array bigger or your bills simpler on its own. It's a way of using more of what you already generate, at the time you actually need it.

6kWh and 12kWh battery builds, and what they cost

Pro-Fit's guide prices are fixed in writing after a free survey. The battery options sit alongside solar on the same table.

A 6kWh battery adds between £1,700 and £1,800 to the solar-only price, depending on how many panels you're fitting. Stepping up to 12kWh adds a further £1,600 to £1,700 on top of that. See the full pricing table for every panel and battery combination together, and the guide prices become a fixed written quote once we've surveyed your roof.

There's no single right battery size for every house. A household that's out at work all day and comes home to cook, charge a car and put the heating on tends to draw down more in the evening than one where someone's in most of the day already using power as it's made. Bring a recent bill to the survey and we'll talk sizing through against what your house actually uses, not just the panel count.

Adding a battery to panels you already have

If you've already got solar, whether from Pro-Fit or another installer, a battery can often be added without replacing the panels. What it depends on is the inverter. Some older inverters aren't battery-ready and need upgrading before a battery can be fitted; a Pro-Fit hybrid inverter, by contrast, is battery-ready from day one on every install we do, battery or no battery at the time.

We can't price this from a phone call. It depends on the make and age of your existing inverter, how the system was wired in, and where a battery can physically go. A survey settles whether your system will take a battery as it stands, and from there the price goes into your written quote.

A battery if you charge an electric car

An EV is one of the biggest single loads in a home, and it rarely lines up neatly with when your panels are generating. Charging overnight on a cheap tariff is one option. Storing daytime solar in a battery and using that in the evening, or topping the battery up overnight at the cheap rate and drawing on it through the next day, is another.

Which makes sense for you depends on your tariff. Some time-of-use tariffs reward exactly this kind of shifting, charging a battery (or a car) overnight at the cheap rate, and some don't offer much of a gap between rates at all. A battery gives you somewhere to put cheap electricity if your tariff allows for it; it doesn't create a cheap rate where none exists. Check what your own supplier offers before assuming the gap between rates is worth having a battery for.

Backup for key circuits

A standard battery and inverter set-up is not automatic whole-home backup, and we won't tell you otherwise. What's possible is keeping specified circuits running during a power cut, things like a fridge-freezer, a router, lighting circuits or a sump pump, depending on how the system is wired and which inverter is fitted.

We don't promise a number of hours a backed-up circuit will run for. That depends on the battery's charge at the moment the power goes, what's drawing from it, and the weather if solar's topping it up at the same time. What we do is specify exactly which circuits can be covered and price that after a survey, so it's agreed in writing rather than left open. Whole-home backup is a separate, larger specification, also priced after a survey.

Brands we fit

Pro-Fit installs batteries and hybrid inverters from Fox ESS, Sigenergy, Sunsynk and Powervault. The brand and model for your installation are named on your written quotation, so you know exactly what's going on your wall before you sign anything.

What's included

Every Pro-Fit battery, fitted alongside solar or added afterwards, comes with the battery itself, set up for off-peak charging where your tariff supports it; a monitoring app configured before we leave, so you can see what the battery's doing from your phone; the grid connection paperwork and handover pack that goes with any change to your system; and help registering for export payments. Where a battery is added to existing panels, the same handover standard applies: nothing's left half-finished.

Guarantees

Our batteries carry a manufacturer warranty of up to 12 years, confirmed in your handover pack once the brand and model for your installation are fixed. The hybrid inverter's warranty is set out on your written quote. Workmanship on the installation itself carries a 2-year Pro-Fit warranty, and if the battery's fitted alongside new panels, those carry a manufacturer warranty of up to 25 years.

A battery's working life comes down to how often it's cycled, not just the calendar. One charged and drained every single day wears through its useful capacity sooner than one topped up a few times a week. Twelve years of manufacturer cover is the benchmark to ask about, whichever brand you're quoted.

How it works, start to finish

A free survey comes first, looking at your roof, your existing system if you have one, and how your household actually uses power through the day. From there you get a written quote with the price fixed, not estimated. You've then got 14 days to change your mind before anything's booked in. Installation follows, and handover includes the app set up and the paperwork done, so the battery's working and registered before we leave.