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Battery storage

Using your own solar is worth roughly twice as much as exporting it. A battery is what lets you do that after dark.

The case for storage

Exporting at 12p to buy back at 25p makes no sense

Here's the whole argument in one line. Electricity you import costs somewhere around 25p per kWh. Electricity you export earns you somewhere around 12p under most Smart Export Guarantee tariffs. Every unit you generate and use yourself is therefore worth roughly double one you sell back.

The trouble is that solar generates at midday and most households use electricity in the evening. A battery bridges that gap: it soaks up the midday surplus and gives it back at six o'clock when the kettle and the oven are on.

On the right tariff you can also charge the battery from the grid overnight at off-peak rates and export at peak, which changes the economics again. We'll model your actual usage rather than quoting a generic payback figure.

  • Fits alongside a new solar installation or retrofits to an existing one
  • Fox ESS hybrid inverters and battery storage, commonly 5kW / 11.5kWh
  • Sized against your real consumption, not a rule of thumb
  • Works with time-of-use tariffs such as Octopus Flux and Agile
  • Full electrical work and DNO notification handled in-house
Two Fox ESS battery modules and a hybrid inverter in an outbuilding

Common questions

Things people usually ask

Can I add a battery to solar panels I already have?
Almost always, yes, and it's one of the most common jobs we do. Depending on your existing inverter we'll either fit an AC-coupled battery alongside it, or replace the inverter with a hybrid unit. We'll tell you which makes more sense for your setup and why.
What size battery do I need?
It depends on your evening consumption more than your roof size. For a typical family home somewhere around 10kWh covers most of an evening. Oversizing wastes money on capacity you never cycle, which is why we ask for your usage data first.
Do batteries need much maintenance?
No. They're sealed units with no serviceable parts. You'll want to keep an eye on the monitoring app, and we'll show you what normal looks like before we leave.
Where does the battery go?
Usually a garage, utility room, loft or an external wall, depending on the unit's temperature tolerance and your available space. We'll agree the location at the survey rather than turning up on the day and improvising.
Is there VAT on battery storage?
Domestic battery storage currently carries 0% VAT, including retrofit to an existing system, until 31 March 2027.

Where we work

Royston, and about half an hour around it

Battery installations and retrofits across the same patch as everything else we do. We're based in Litlington, just outside Royston, and cover Hertfordshire, Cambridgeshire, Essex and Bedfordshire from there: Royston, Melbourn, Baldock, Letchworth Garden City, Hitchin, Stevenage, Welwyn, Hertford, Saffron Walden, Cambridge, Buntingford, Duxford and the villages in between. Close enough to come back if you ever need us.

Get started

Free, no-obligation survey and quote

Tell us a bit about your property and we'll come and look at it. You'll get a straight answer either way, including if solar isn't the right fit.

Get a free quote Call 07971 199 642