Battery Storage

Yes — and it's a more common request than it used to be. A home battery doesn't need panels to be useful, because a battery isn't a generator. It's a store. Panels are simply one way of filling it; a cheap-rate electricity tariff is another. We fit battery-only systems as standalone retrofits across Hampshire, the Isle of Wight, Dorset, West Sussex, East Sussex and Surrey, and plenty of them go into homes with a roof that will never see a panel — north-facing, shaded, listed, or simply a household that doesn't want the disruption.

The maths is straightforward once you stop thinking about generation. On a cheap-rate import tariff such as Intelligent Octopus Go, units bought in the small hours cost around 7p per kWh, while the standard day rate sits at roughly 26p. You charge the battery overnight at the low rate, then run the house from stored electricity through the expensive part of the day. Every kWh you shift is the difference between those two prices — somewhere in the region of 19p — and a Tesla Powerwall 3 holds 13.5kWh. What that's worth to you depends entirely on how much you actually use during peak hours, which is the first thing we'd look at rather than the last.

That's also why the sums hold up with no panels at all. A solar battery's case is usually built partly on export income, and export rates have been moving the wrong way: Octopus Outgoing Fixed was cut from 15p to 12p on 1 March 2026, and open-market flat SEG rates sit at roughly 10.5p to 16.5p. A battery-only system doesn't lean on any of that. It earns from the gap between your own import prices, which is a much more predictable thing to plan around.

On cost, a Tesla Powerwall 3 retrofit at 13.5kWh starts from £7,450, with expansion to 27kWh from £13,950 for households running heavy loads. Both are "from" prices and subject to survey — siting, cable runs and the state of your existing board all move the figure, and we'd rather quote you properly after a look than guess over the phone. We're a Tesla Certified Installer, which is a scarce accreditation and one of the reasons we'd point you at Powerwall for a battery-only job.

One piece of process worth knowing before you commit: any system with battery storage needs a G99 application approved by the distribution network operator before installation, not afterwards. It isn't the connect-and-notify route that small solar arrays take. We file it for you. Locally that means SSEN for Hampshire, the Isle of Wight, Dorset and west Surrey, and UK Power Networks for East and West Sussex and most of Surrey. As for who it genuinely suits: EV owners already on a cheap overnight tariff, heat-pump homes with real winter demand, and anyone on a rural line who's tired of losing power in a storm.